Micro And Genetics

Front 1

Classify as correct organism type :

influenza

Back 1

virus

Front 2

Classify as correct organism type :

tinea

Back 2

fungus

Front 3

Classify as correct organism type :

red tide

Back 3

algae

Front 4

Describe why some soil organisms may produce antimicrobial substances

Back 4

Because they are in competition with othermicrobes.

Front 5

Briefly outline how a GMO can be created to produce insulin

Back 5

The genetic information from pigs tocreate insulin was copied to the genetic code of yeast, with was then bread toproduce insulin in large quantities

Front 6

Give microbial examples of nitrogen cycling

Back 6

Legume plants (eg lentils, peas) have bacteriapresent in their root nodules that convert nitrogen from the atmosphere (N2)into fixed nitrogen the plants can use for growth (NH3)

Front 7

Give microbial example of carbon dioxide cycling

Back 7

Microorganisms take part in nutrient cycling, e.g. of carbon and sulphur, convert these elements into forms that can be taken up by plants

Carbon dioxide sink

Front 8

Briefly explain how ruminants contribute to global warming

Back 8

Methane produced by their gut microbes as a biproduct breaking down cellulose

Front 9

Define bioremediation

Back 9

Some microorganisms will break downpollutants, such as oil, pesticides and solvents

Front 10

Explain how stromatolites contribute to a liveable planet

Back 10

The oxygen present in the atmosphere isdue to microbial activity – by photosynthetic cyanobacteria that first existedmore than 3.5 billion years ago

Front 11

Briefly describe why microbes evolve so quickly

Back 11

Microbes have a very short life cycle compared to larger organisms, so have more chances to mutate in the same time frame.

Front 12

Describe why the human body is an ecosystem

Back 12

9 out of 10 cells in a human body are not ‘human’ cells, but are instead microbes, mostly bacteria.

Front 13

. Give examples of biofilms

Back 13

Moss growing on a rock

Staphylococcus growing on a catheter

Plaque build up on the surface of teeth

A colony of Staphylococcus growing on a nutrient agar plate

Front 14

Explain factors that limit uncontrolled growth of microbes

Back 14

5. Limits on food, space and energy

Front 15

State the dimension of a staphylococcal cell

Back 15

Up to 1 µm in diameter

Front 16

Explain why a virus is not a cell

Back 16

Viruses do not replicate independently,only replicate once they have infected another cell. Have no ribosomes. Rely onthe host cell for protein production.

Front 17

List features that make viruses different from bacteria

Back 17

Bacteria – have ribosomes, cell walls, can replicate, larger (c. 1000nm), treated with antibiotics

Viruses – no ribosomes or cell walls, need other cells to replicate, have DNA or RNA enclosed in a coat of protein, smaller (c. 20-400nm), treated with an antiviral.

Front 18

Describe how the genetic information is arrangedin bacterial cells

Back 18

Circular genome in a nucleoid.

Many haveplasmids (extrachromosomal circular DNA) with genes that have particularproperties eg. Antibiotic resistance.

Front 19

Explain the origin of mitochondria

Back 19

A bacterial cell was engulfed by an ancient eukaryotic cell, they developed a symbiotic relationship (endosymbiosis)

Front 20

Explain how Pasteur disproved spontaneous generation

Back 20

With an experiment with swan necked flasks and the boiling of samples showed that samples remained sterile unless contaminated.

Front 21

Describe an experiment to prove an organism causes a specific disease

Back 21

5. Koch’s Postulates:

1. Microorganisms are isolated from a deadanimal

2a.microorganisms are grown in pure culture2b.microorganisms are identified

3. microorganisms are injected into a healthyanimal

4. disease is reproduced in the second animal,microorganisms are isolated from this animal

5a. these microorganisms are grown in pureculture

5b. identical microorganisms are identified

Front 22

Hershey and Chase experiment

Back 22

Did not know if DNA or Protein entered the E. coli cells to produce new phage particles

•grew T2 in either - 35S labeled protein or 32P labeled DNA

•infected E.coli with T2

- briefly separated E.coli and T2

•DNA of the virus infected the host cell

•Protein remained outside the cell

Front 23

The transforming principle

Back 23

The transforming principle wasan early name for DNA. In1928, scientists didn't know yet that DNA carried genetic information, but theyknew that there was something that could cause bacteria to transform fromone type to another.

Front 24

The transforming principle

Back 24

The transforming principle wasan early name for DNA. In1928, scientists didn't know yet that DNA carried genetic information, but theyknew that there was something that could cause bacteria to transform fromone type to another.

Front 25

Avery, MacLeod and McCartney experiments

Back 25

They purified and treated heat killed Streptococcus pneumonia bacteria to determine the chemical nature of the “transforming principle”

-Treated four mixtures of polysaccharides, proteins, DNA and RNA with enzymes to degrade one of those macromolecules

- Only DNA transformed non pathogenic bacteria into pathogenic

Front 26

basic nucleotide structure

Back 26

Front 27

. the difference betweenpurines and pyrimidines

Back 27

Purinesand Pyrimidines are nitrogenous bases that make up the two differentkinds of nucleotide bases in DNA and RNA.

-Purines -The two-carbon nitrogen ring bases(adenine and guanine)

- Pyrimidines - one-carbon nitrogen ring bases (thymine and cytosine)

Front 28

. the difference between purines and pyrimidines

Back 28

-Purines -The two-carbon nitrogen ring bases(adenine and guanine)

- Pyrimidines - one-carbon nitrogen ring bases (thymine and cytosine)

Front 29

the base pairing rules

Back 29

A=T G=C (A=U for RNA)

Front 30

Chargaff’s rules

Back 30

DNA from any cellof all organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases- G=C and A=T

Front 31

Chargaff’s rules

Back 31

DNA from any cellof all organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases- G=C and A=T

Front 32

DNA replication process as it occurs at the replicating fork

Back 32

During DNA replication a DNA double helix must unwind and separate

-DNA polymerase enzymes use each single strand as a template for the synthesis of a new double strand.

- Strand separation is catalyzed by a Helicase enzyme.

Front 33

leading strand

Back 33

synthesized in the 5’-3’direction (direction the same as the replication fork movement)

-it is synthesized continuously; there are no breaks in-between.

-it is formed as nucleotides are continuously added to the 3’ end of the strand after polymerase reads the original DNA template.

Front 34

lagging strand

Back 34

-the strand which is synthesized in the 3’-5’ direction (oppositeto the movement of the replication fork)

-It grows or is synthesized away from the fork. - it is synthesized in fragments.

-The primase, which is responsible for adding an RNAprimer, has to wait for the fork to open before putting in the primer.

-The lagging strands have fragments of DNA which are calledOkazaki fragments.

Front 35

DNA polymerase

Back 35

enzymes which are responsible forsynthesizing DNA

-add nucleotides one by one to the growing DNAchain

- require a template and a primer (starter)

-synthesize DNA in the 5' to 3' direction.

Front 36

DNA ligase

Back 36

a DNA-joining enzyme.

-If two pieces of DNA have matching ends, ligase can link them to form a single, unbroken molecule of DNA.

Front 37

proofreading,

Back 37

During DNA replication (copying), most DNApolymerases can “check their work” with each base that they add.

-If the polymerase detects that a wrong(incorrectly paired) nucleotide has been added, it will remove and replace thenucleotide right away, before continuing with DNA synthesis

Front 38

telomeres.

Back 38

Eukaryote chromosomes have telomeres at the ends (t-loop model)

•telomeres do not contain genes

•telomeres contain multiple repeats of short nucleotide sequence

•100-1000 copies of repeats

•repeat sequences are evolutionarily conserved

•in humans & all vertebrates repeat sequence is 5’- TTAGGG -3’

Front 39

What type ofmicroorganism is the primary cause of Tinea?

(a) Bacteria

(b) Fungus

(c) Virus

(d) Archaea

(e)Parasite

Back 39

b) fungus

Front 40

The use of microorganisms to break down pollutants is known as:

(a) bioinformatics

(b) bio recycling

(c) bioprocessing

(d) bioremediation

(e) biosynthesis

Back 40

d) bioremediation

Front 41

Which of the following best describes why some soilmicroorganisms produce antimicrobial substances?

(a) To protect themselvesfrom other microorganisms

(b) To improve soil quality

(c) To inhibit the growth of othermicroorganisms

(d) To aid the production ofbiofilms

(e) To inhibit the growth ofviruses

Back 41

c) to inhibit the growth of other microorganisms

Front 42

Which of the following is not an example of a biofilm?

(a) Moss growing on a rock

(b) Staphylococcus growing on a catheter (c) Plaque build upon the surface of teeth (d) Algal growth of the surface of the water in a swimming pool

(e) A colony of Staphylococcus growing on a nutrient agar plate

Back 42

d) Algal growth on the surface water in a swimming pool

Front 43

Which of the following is not true about bacterial cell walls?

(a) Maintain cell shape

(b) Prevent the cell from bursting

(c) Attachment site for appendages such as flagella

(d) Contain peptidoglycan

(e) The gram-negative cell wall is thicker than the gram-positive cell wall

Back 43

(e) The gram-negativecell wall is thicker than the gram-positive cell wall

Front 44

Which of thefollowing is not a eukaryotic cell? (a)Algae

(b)Tinea mould

(c)Giardia

(d)Yeast

(e) Influenza

Back 44

e) influenza

Front 45

Which of the following is not a eukaryotic cell?

(a)Algae

(b)Tinea mould

(c)Giardia

(d)Yeast

(e) Influenza

Back 45

e) influenza

Front 46

Prokaryoticcells have evolved quickly due to:(a) Mitosis

(b) Meiosis

(c) Binary fission

(d) Endocytosis

(e) Apoptosis

Back 46

c) Binary fission

Front 47

A news paper report describes that the salmonella virus is the majorcause of food poisoning. This:

(a)is correct as salmonella virus is the major cause of food poisoning

(b) is incorrect as E. colicauses more cases of food poisoning

(c) is correctas viruses are members of the flora of the intestine

(d) isincorrect as salmonella does not cause food poisoning

(e) isincorrect as salmonella will respond to antibiotics so can’t be a virus

Back 47

e) is incorrect as salmonella will respond toantibiotics so can’t be a virus

Front 48

A news paper report describes that the salmonella virus is the major cause of food poisoning. This:

(a)is correct as salmonella virus is the major cause of food poisoning

(b) is incorrect as E. coli causes more cases of food poisoning

(c) is correct as viruses are

members of the flora of the intestine

(d) is incorrect as salmonella does not cause food poisoning

(e) is incorrect as salmonella will respond to antibiotics so can’t be a virus

Back 48

e) is incorrect as salmonella will respond to antibiotics so can’t be a virus

Front 49

Which of the following diseasesis caused by a virus?

(a)Wound infections

(b)Cold sores

(c)Anthrax

(d)Red tide

(e) Giardia

Back 49

b) cold sores

Front 50

Which of the following diseases is caused by a virus?

(a)Wound infections

(b)Cold sores

(c)Anthrax

(d)Red tide

(e) Giardia

Back 50

b) cold sores

Front 51

A polymorph is about 10 times wider than astaphylococcal cell. Therefore a polymorphs width is:(a) 1 nm (b) 1 um (c) 1 cm (d) 10 nm (e) 10 um

Back 51

e) 10um

Front 52

Viruses differ from bacteria because viruses:

(a) are true cells

(b) have a cell wall

(c) do not contain genetic material

(d) only grow on selective agar plates

(e) are not able to metabolise

Back 52

e) are not able to metabolise

Front 53

A scientistwishes to prove an organism is the cause of stomach ulcer. The scientist: (a) should not experiment with this as stresscauses stomach ulcers

(b) should grow the organisms from thestomach and feed them to rabbits

(c) should grow the organisms from thestomach and feed them to mice as these are model organisms for human diseases (d) study and isolate a single organismbefore finding an animal model to test

(e) not bother as the stomach is too acid forany type of bacteria to grow

Back 53

(d) study and isolate a single organism before finding an animal model to test

Front 54

A scientist wishes to prove an organism is the cause of stomach ulcer. The scientist:

(a) should not experiment with this as stress causes stomach ulcers

(b) should grow the organisms from the stomach and feed them to rabbits

(c) should grow the organisms from the stomach and feed them to mice as these are model organisms for human diseases

d) study and isolate a single organism before finding an animal model to test

(e) not bother as the stomach is too acidic for any type of bacteria to grow

Back 54

(d) study and isolate a single organism before finding an animal model to test

Front 55

Viruses:

(a) are the most primitive type of cell (b) are not able to infected bacteria

(c) causeinfections that can sometimes be treated with chemotherapy

(d) canonly divide when inside cells

(e) allof the above

Back 55

c) cause infections that can sometimes be treated with chemotherapy

Front 56

Extrachromosomal DNA that can replicate independently of the hosts chromosome are known as:

(a) Plasmids

(b) Phages

(c) Ribosomes

(d) mRNA

(e) Histones

Back 56

a) Plasmids

Front 57

Which of the following names does not represent a genus of bacteria?

(a) Esherichia

(b) Epidermidis

(c) Staphylococcus

(d) Pseudomonas

(e) Klebsiella

Back 57

b) Epidermidis

Front 58

In Pasteur’s experiment with the swan necked flask he:

(a) Proved the theory of Spontaneous generation

(b) Proved the theory of Spontaneous generation was incorrect

(c) Discovered endospores were extremely resistant to heat

(d) Discovered that a specific organism was required to cause a specific disease

(e) Discovered pure cultures of pathogen could be obtained from an animal with a specific disease

Back 58

(b) Proved the theory of Spontaneous generation was incorrect

Front 59

Outline when a light microscope and electron microscope are useful

Back 59

Light microscopes look at whole cells, electron microscopes look at internal cellstructures and viruses

Front 60

resolution

Back 60

The smallest distancebetween two points where you can see the two dots are separate.

Front 61

identify the limit ofresolution for most light microscopes

Back 61

Lightmicroscopes have a limit of resolution of ~ 0.2 mm = 200 nanometres (nm)

Front 62

Explain why immersion oil is used forlight power light microscopy

Back 62

. increases the light-gathering ability of the lens - oil removes light diffraction

Front 63

Name the parts on a lightmicroscope

Back 63

Front 64

Explain why immersion oil is used for light power light microscopy

Back 64

. increases the light-gathering ability of the lens - oil removes light diffraction

Front 65

Contrast gram-positive andgram-negative cell wall structure

Back 65

Gram-positive cell walls have a thicker layer of peptidoglycan

-Gram-negative cell walls have a complex, multilayered structure

-Gram negative bacteria contain an outer membrane in addition to peptidoglycan

- Made up of phospholipid, protein and polysaccharide, often called the lipopolysaccharide layer or LPS

-The main function is to provide cell structure, LPS is often toxic to animals – known as endotoxin

Front 66

Explain what is meant by 'heat fixation’

Back 66

heat fixing causes the cells to adhere to the glass slide,

the heat kills most of the cells

Front 67

the importance of endotoxin

Back 67

Endotoxin is often toxic to animals if the bacteria is destroyed (ie. by sterilisation)

Front 68

why Mycoplasma spp. areimportant

Back 68

Some bacteria and archea exist without cell walls –

-known as spheroplasts or protoplasts

-One important group are the mycoplasmas

-Smallest organisms capable of independent growth

- Parasitic, many are pathogenic, resistant to lysozyme and cannot be killed with antibiotics such as penicillin and vancomycin because they lack a cell wall

Front 69

Identify bacterial cell morphologies and arrangements

Back 69

round in shape are called cocci

cylindrical are called rods (bacilli)

Some rods are curved or spiral

some bacteria remain in groups:

chains and clusters

Some are:

-filamentous, form long, thin cells

have tapering ends (fusiform),

- branching

Front 70

Outline the steps formaking blood agar

Back 70

Shave and apply antiseptic to the surface of the animal blood is to be collected from

-collect the blood while avoiding contaminating it as much as possible

-put it in cold to prevent contaminants multiplying

-cool sterilised agar

-add blood to agar aseptically to prevent airborne contaminents

Front 71

the importance of endotoxin

Back 71

Endotoxin is often toxic to animals if the bacteria is destroyed (ie. by sterilisation)

Front 72

Which of the following cannot be viewed with a light microscope?

a. Influenza virions

b. E. coli

c. Giardia cysts

d. Yeast cells

e. Bacillus Endospores

Back 72

a. Influenza virions

Front 73

The ability to see two objects as being separate is known as:

a. Refraction

b. Illumination

c. Magnification

d. Resolution

e. Focus

Back 73

d. Resolution

Front 74

Outline the steps for making blood agar

Back 74

Shave and apply antiseptic to the surface of the animal blood is to be collected from

-collect the blood while avoiding contaminating it as much as possible

-put it in cold to prevent contaminants multiplying

-cool sterilised agar

-add blood to agar aseptically to prevent airborne contaminents

Front 75

Prokaryotic cells range in size from:

a. 0.01 - 0.3 μm

b. 0.3 - 5 μm

c. 5 - 10 μm

d. 10 – 15 μm

e. 15 – 20 μm

Back 75

b. 0.3 - 5 μm

Front 76

. To increase the magnification of a specimen using a light microscope you:

a. Move to an objective lens with a higher aperture

b. Move to an objective lens with a lower aperture

c. Move the stage up

d. Move the stage down

e. Increase the intensity of light

Back 76

a. Move to an objective lens with a higher aperture

Front 77

. To increase the magnification of a specimen using a light microscope you:

a. Move to an objective lens with a higher aperture

b. Move to an objective lens with a lower aperture

c. Move the stage up

d. Move the stage down

e. Increase the intensity of light

Back 77

a. Move to an objective lens with a higher aperture

Front 78

7. Oil immersion is used in light microscopy to:

a. Increase the light gathering ability of the lens

b. Reflect light away from the objective

c. Protect the stain from rubbing off the slide

d. Lubricate the objective lens to prevent damage

e. View internal cellular structures

Back 78

a. Increase the light gathering ability of the lens

Front 79

8. Which of the following is not a part of the Light microscope?

a. Ocular

b. Condenser

c. Objective lens

d. Fine focus adjustment knob

e. Course focus lens

Back 79

e. Course focus lens

Front 80

The Gram stain is a useful differential technique in bacteriology because it exploits differences in bacterial:

a. Capsules

b. Plasma membranes

c. Cell walls

d. Plasmids

e. All of the above

Back 80

c. Cell walls

Front 81

What is the correct order of steps in the Gram stain?

a. carbol fuschin, iodine, acetone, crystal violet

b. carbol fuschin, acetone, iodine, crystal violet c. crystal violet, acetone, iodine, carbol fuschin d. crystal violet, iodine, acetone, carbol fuschin e. crystal violet, carbol fuschin, acetone, iodine

Back 81

d. crystal violet, iodine, acetone, carbol fuschin

Front 82

What is the role of acetone in the Gram stain?

a. Fixation of bacteria to the slide

b. Traps the crystal violet-iodine complex in the gram-negative cell wall

c. Removes the crystal violet-iodine complex from gram-positive cells

d. Removes the crystal violet-iodine complex from gram-negative cells

e. Decolourises gram-positive and gram-negative cells

Back 82

d. Removes the crystal violet-iodine complex from gram-negative cells

Front 83

12. A major constituent of gram-positive cell walls is:

a. Peptidoglycan

b. An outer membrane

c. Lipopolysaccharides

d. Lipoproteins

e. Enterotoxin

Back 83

a. Peptidoglycan

Front 84

13. Why is it important to incubate Petri dishes upside down?

a. Plates need to be incubated upside down for bacteria to grow

b. Prevents condensation from dripping on the agar

c. Allows condensation to accumulate on agar

d. It makes stacking multiple plates easier e

. So that bacteria do not penetrate the agar

Back 84

b. Prevents condensation from dripping on the agar

Front 85

Which of the following describes a gram-positive and gram-negative microorganism?

a. Staphyloccus aureus and Streptococcus pyogenes

b. Staphyloccus epidermidis and Bacillus subtilis

c. Streptococcus pyogenes and E. coli

d. Giardia lamblia and E.coli e. None of the above

Back 85

c. Streptococcus pyogenes and E. coli

Front 86

15. Penicillin works by:

a. Dissolving the outer membrane of prokaryotic cells

b. Inhibiting protein synthesis

c. Interfering with the strength of peptidoglycan

d. Causing DNA to coagulate

e. Initiating mutations in genetic material

Back 86

c. Interfering with the strength of peptidoglycan

Front 87

16. Mycoplasmas differ from most bacteria because they:

a. are not pathogenic

b. do not have a cell wall

c. do not have a cytoplasmic membrane

d. do not carry the metabolic machinery required for replication

e. can only be grown in a cell culture

Back 87

b. do not have a cell wall

Front 88

17. A smear made from an infected wound reveals lots of pus cells contains gram-positive cocci in chains the most likely cause of the infection is:

a. Bacillus subtilis

b. Clostridium tentani

c. Staphyloccus aureus

d. Staphyloccus epidermidis

e. Streptococcus pyogenes

Back 88

e. Streptococcus pyogenes

Front 89

18. A patient is diagnosed with a urinary tract infection caused by Staphyloccus aureus . What would you see in a Gram stain?

a. Clusters of gram-positive cocci

b. Chains of gram-positive cocci

c. Gram-negative bacilli singularly and in small chains

d. Gram-positive bacilli in small chains and clusters

e. Gram-positive filamentous rods

Back 89

a. Clusters of gram-positive cocci

Front 90

Why is streak plating an important technique in microbiology?

a. It allows you to see separate colonies from a mixture

b. It allows you to see if you have a pure culture

c. It allows you to calculate the number of microorganisms in a sample

d. (a) and (b) are correct

e. All of the above are correct

Back 90

d. (a) and (b) are correct

Front 91

A component of the outer membrane of gram-negative bacteria the often triggers an inflammatory response in animals and humans is known as:

a. Mycotoxin

b. Aflatoxin

c. Endotoxin

d. Exotoxin

e. Enterotoxin

Back 91

c. Endotoxin

Front 92

Should the air holes of the Bunsen Burner be opened or closed?

Back 92

open

Front 93

What is the hottest part of the flame?

Back 93

which is at the tip of the blue part of the flame.

Front 94

Why do we flame the slide before using it?

Back 94

To get rid of any grease or marks on the glass that may interfere with the stain sticking to it.

Front 95

What is the first stain used on the smear, and what is its colour?

Back 95

Crystal Violet.( Purple)

Front 96

What is the last stain used and what is its colour?

Back 96

Dilute carbol fuchsin. (Dark pink.)

Front 97

How long is the acetone on the slide for?

Back 97

No longer than 2 seconds.

Front 98

Why do you work close to the bunsen burner during aseptic technique

Back 98

To reduce the risk of aerial contamination of our work.

Front 99

Where is the lid of the bottle we are subculturing from kept?

Back 99

Held in our hand by our little finger

Front 100

What is the " primary inoculum"?

Back 100

The area of the plate where the material ( on a loop or swab) is spread out over approximately 1/3 to 1/4 of the agar.

Front 101

When is the loop flamed during aseptic technique?

Back 101

Between each set of streak lines.

Front 102

Back 102

lambda

Front 103

1. You are about to pick up a petri dish that contains a culture of bacteria (Staphylococcus aureus) known to cause a wound infection. Before picking up the agar plate you should:

a) -make sure the lid is on the petri dish

b) put a dressing on any cuts on hands

c) all of the above

d) wash your hands

e) put on gloves

Back 103

b) puta dressing on any cuts on hands

Front 104

A student contaminates their families food preparation area at home with bacteria from their laboratory practical. The most likely reason for this was

a) the student sucked the end of their pen in class

b) the student was infected with the bacteria during the prac class

c) the student used their mobile phone during the class

d) the student coughed in the food preparation area

e) the student breathed in the bacteria during the prac class

Back 104

c) thestudent used their mobile phone during the class

Front 105

Sodium hyperchlorite is used in the laboratory to

a) clean microscope lenses

b) to sanitise the air

c) wash hands before leaving the laboratory d) wipe benches before leaving the laboratory e) to put out fires

Back 105

d) wipebenches before leaving the laboratory

Front 106

a) The only type of disposal bag that should be used in the laboratory

b) The bag where all experimental materials should be placed

c) Special bag for sharps

d) the disposal bag for paper waste

e) disposal suitable for non-sharp experimental materials

Back 106

e) disposal suitable for non-sharp experimental materials

Front 107

a) is suitable for use in laboratories for disposal of paper towels used to dry washed hands

b) should not be used in laboratories

c) has the wrong bin liner in it

d) is suitable for all disposable laboratory materials

e) can be used for all laboratory plastics

Back 107

a) issuitable for use in laboratories for disposal of paper towels used to dry washed hands

Front 108

Glass slides can be placed in

a) laboratory waste with petri dishes

b) laboratory autoclave bins with recyclable glass

c) the plain waste bins

d) the yellow autoclave bags

e) the yellow sharp bins

Back 108

e) theyellow sharp bins

Front 109

a) should not be used in laboratories

b) is a fire hazard in laboratories

c) should be disposed of in a biohazard bag after cleaning up a spill

d) should be used to line the laboratory bench

e) should be disposed of in biohazard bags after drying hands

Back 109

c) should be disposed of in a biohazard bag aftercleaning up a spill

Front 110

Which of the following is incorrect?

a) Practical books should be kept separate from cultures on the bench

b) Practical books should not be near the bunsen burner

c) The paper clip should be disposed of in a sharps container as it may break bags used for disposal

d) Anything disposed of in the laboratory should go into hazardous waste

e) Pages of your laboratory records can be removed and discarded

Back 110

d) Anythingdisposed of in the laboratory should go into hazardous waste

Front 111

Should glass slidesbe placed in this container?

a) Yes, if disposed of in autoclave bags they could puncture the bags and thus injure people carrying the bags

b) No, they should be recycled

c) No, this container is for needles only

d) No, they should be placed in the autoclave bin

e) No, they should be put with paper waste

Back 111

a) Yes, if disposed of in autoclave bags they couldpuncture the bags and thus injure people carrying the bags

Front 112

When washing hands, you should wet your handsbefore adding liquid soap to your hands

a) No, because it dilutes the liquid soap

b) No, because you will contaminate the soap

c) Yes, because the liquid soap may be irritating to hands

d) Yes, because you need less soap

e) Yes, because the water activates the liquid soap

Back 112

c) Yes, because the liquid soap may be irritating to hands

Front 113

During a prac class you accidentally burn your hand. It is only a minor burn and it no longer hurts. You should

a) Still place your hand under cold water even though it has stopped hurting

b) tell your partner

c) tell your demonstrator

d) record the details of the incident so that your demonstrator can file an incident report

e) all of the above

Back 113

e) all of the above

Front 114

Which is a better surface disinfectant, 70% alcoholor 1% hypochlorite solution?

a) Alcohol because it is very good at killing bacteria and viruses

b) Hypochlorite because it is very good at killing bacteria and viruses

c) Alcohol because it evaporates quickly

d) Hypochlorite because it evaporates quickly

e) Neither should be used as a surface disinfectant

Back 114

b) Hypochlorite because it is very good at killingbacteria and viruses

Front 115

In prac class you spill a bacterial culture on the bench. You should

a) Order an evacuation

b) Call the demonstrator so that the demonstrator can clean it up

c) Put on gloves and use a paper towel to mop up the excess liquid and dispose of this paper in the metal bin

d) Put on gloves and use a paper towel to mop up the excess liquid and dispose of this paper in the paper bin

e) Put on gloves and use a paper towel to mop up the excess liquid and then surface disinfect the area with 70% alcohol

Back 115

e) Put on gloves and use paper towel to mop up the excess liquid and then surface disinfect the area with 70% alcohol

Front 116

During prac class your lab partner cuts open their hand. The first thing you should do before bandaging the cut is

a) Wash the hand with soap and warm water

b) Don't wash the hand as it will allow bacteria to enter the cut

c) Use the alcohol on the bench to disinfect the cut

d) Use the hypochlorite on the bench to disinfect the cut

e) Call a demonstrator

Back 116

a) Wash the hand with soap and warm water

Front 117

Which of the follwoing best describes hand washing?

a) most effective if hands dried thoroughly

b) apply soap to dry hands to stop dilution

c) avoid using paper towels as they are not effective

d) solid soap is better than liquid soap

e) wash hands at the beginning and end of lab classes

Back 117

a) m ost effective if hands dried thoroughly

Front 118

Which is a better surface disinfectant, 70% alcoholor 1% hypochlorite solution?

a) Alcohol because it is very good at killing bacteria and viruses

b) Hypochlorite because it is very good at killing bacteria and viruses

c) Alcohol because it evaporates quickly

d) Hypochlorite because it evaporates quickly

e) Neither should be used as a surface disinfectant

Back 118

b) Hypochlorite because it is very good at killing bacteria and viruses

Front 119

What must you always wear in a microbiology laboratory?

a) hat, shoes and apron

b) gown, googles and a hat

c) shoes, gown, gloves

d) gown, shoes and mask

e) shoes, gown and sometimes goggles

Back 119

e) shoes, gown and sometimes goggles

Front 120

When are gloves worn in a microbiology laboratory?

a) When working with agar plates

b) Always when performing staining procedures

c) When working with blood and body fluids

d) When using a bunsen burner

e) All of the above

Back 120

c) When working with blood and body fluids

Front 121

What should you do if you get some staining chemicals in your eye?

a) Scream uncontrollably

b) Hide your disfugured (stained) face from your partner

c) Ask for your partners assistance to find the eye wash

d) Put your hand up and hope the demonstrator doesn't take too long to see you e) Complete the facial decoration by using some other stain colours

Back 121

c) Ask for your partners assistance to find the eye wash

Front 122

Which enzyme Prevents DNA from tangling up as the replication fork migrates during replication?

a) DNA helicase

b) DNA gyrase

c) DNA polymerase III

d) DNA polymerase I

e) topoisomerase

Back 122

b) DNA gyrase

Front 123

Watson and Crickproposed the ________ model of DNA replication.

a) conservative

b) semiconservative

c) dispersive

d) semidispersive

e) semidiscontinuous

Back 123

b) semiconservative

Front 124

In the semiconservative model of DNA replication, progeny double helices consist of

a) one parental DNA strand and one new strand.

b) two new DNA strands.

c) two parental DNA strands.

d) one parental DNA strand and one new RNA strand.

e) two new RNA strands.

Back 124

a) one parental DNA strand and one new strand.

Front 125

Which of the following is required for the synthesis of DNA during replication?

a) dNTPs

b) magnesium ions

c) template DNA

d) DNA polymerase

e) all of the above

Back 125

e) all of the above

Front 126

During replication, the direction of synthesis of new DNA from the leading strand is

a) 5' to 3' only.

b) 3' to 5' only.

c) from left to right only.

d) both 5' to 3' and 3' to 5'

e) none of the above

Back 126

a) 5' to 3' only

Front 127

During replication, the direction of synthesis of new DNA from the lagging strand is

a) 5' to 3' only.

b) 3' to 5' only.

c) from left to right only.

d) both 5' to 3' and 3' to 5'

e) none of the above

Back 127

a) 5' to 3' only.

Front 128

In the bacterium Escherichia coli, DNA replication is

a) unidirectional and dispersive.

b) bidirectional and semiconservative.

c) unidirectional and semiconservative.

d) dispersive and semiconservative.

e) bidirectional and dispersive.

Back 128

b) bidirectional and semiconservative.

Front 129

Prior toreplication, the DNA double helix must be untwisted by which type of enzyme?

a) helicase

b) primase

c) polymerase

d) topoisomerase

e) ligase

Back 129

a) helicase

Front 130

At the growing endof a DNA chain, DNA polymerase catalyzes the formation of a ________ bondbetween nucleotides.

a) hydrogen

b) disulfide

c) glycosidic

d) phosphodiester

e) phosphate

Back 130

d) phosphodiester

Front 131

When do you stop wearing a lab gown?

a) When the boss walks into the laboratory

b) When the temperature of the laboratory rises to uncomfortable levels

c) When experiments are finished and you are writing up results

d) When required to answer a phone

e) When in the corridor outside the laboratory

Back 131

e) When in the corridor outside the laboratory

Front 132

In Escherichia coli, replication begins at which chromosome site?

a) ori

b) the replication fork

c) att

d) the RBS

e) none of the above

Back 132

a) ori

Front 133

Okazaki fragmentsare made from the ________ strand of the DNA double helix.

a) leading

b) lagging

c) conservative

d) continuous

e) dispersive

Back 133

b) lagging

Front 134

After removal ofthe RNA primers, Okazaki fragments are joined through a reaction that involveswhich enzyme?

a) DNAprimase

b) DNA polymerase

c) DNAligase

d) RNApolymerase

e) DNAhelicase

Back 134

c) DNA ligase

Front 135

After a region ofDNA has been replicated, ________ removes the RNA primers.

a) DNApolymerase I

b) DNApolymerase II

c) DNApolymerase III

d) DNAhelicase

e) DNAprimase

Back 135

a) DNA polymerase I

Front 136

Which of thefollowing enzymes plays an important role in DNA replication?

a) DNApolymerase III

b) DNAhelicase

c) DNAligase

d) DNAprimase

e) allof the above

Back 136

e) all of the above

Front 137

In eukaryotes, chromosomes are duplicated during which stage of the cell cycle?

a) G1

b) S

c) G2

d) M

e) C1

Back 137

b) S

Front 138

In eukaryotes, DNA replication

a) is initiated at several sites on chromosomes.

b) occurs bidirectionally.

c) is semidiscontinuous.

d) all of the above

e) none of the above

Back 138

d) all of the above

Front 139

The number of replicons in a typical Escherichia coli cell is

a) 1.

b) 10.

c) 100.

d) 1,000.

e) 10,000.

Back 139

a) 1

Front 140

In eukaryotes,which enzyme is responsible for replicating the ends of the chromosomes?

a) DNApolymerase I

b) telomerase

c) DNAprimase

d) RNApolymerase

e) DNAgyrase

Back 140

b) telomerase

Front 141

In eukaryotes, DNA replication begins at

a) a single origin of replication on each chromosome.

b) a single origin of replication for each nucleus.

c) multiple origins of replication on each chromosome.

d) all of the above

e) none of the above

Back 141

c) multiple origins of replication on each chromosome.

Front 142

In eukaryotes, DNA replication is

a) unidirectional.

b) bidirectional.

c) semiconservative.

d) both A and C

e) both B and C

Back 142

e) both B and C

Front 143

An ARS isthe site of origin of replication in

a) E.coli

b) yeast

c) Drosophila

d) humans

e) allof the above

Back 143

b) yeast

Front 144

In eukaryotes,which enzyme is responsible for replicating the ends of the chromosomes?

a) DNA polymerase I

b) telomerase

c) DNA primase

d) RNA polymerase

e) DNA gyrase

Back 144

b) telomerase

Front 145

The ________ geneencodes wild-type DNA polymerase in E. coli.

a) dnaB

b) polA

c) oriC

d) polAex1

e) exoIII

Back 145

b) polA

Front 146

Which enzyme activityis associated with DNA polymerase I?

a) 5'to 3' exonuclease

b) 3'to 5' exonuclease

c) 5'to 3' polymerase

d) bothB and C

e) allof the above

Back 146

e) all of the above

Front 147

The ________ gene encodes wild-type DNA polymerase in E. coli.

a) dnabB

b) pol A

c) ori C

d) pol Aex1

e) exoIII

Back 147

b) polA

Front 148

________ prevents the separated strands of double stranded DNA from reannealing during replication.

a) DNA polymerase

b) DNA primase

c) Single strand binding protein

d) Topoisomerase

e) Reverse transcriptase

Back 148

c) Single strand binding protein

Front 149

In E. coli, theerror rate associated with replication is

a) 1/1,000,000,000

b) 1/1,000,000

c) 1/100,000

d) 1/10,000

e) 1/1,000

Back 149

a) 1/1,000,000,000

Front 150

In eukaryotes, a replicon is

a) asingle chromosome.

b) theentire genome.

c) thedistance between adjacent origins of replication.

d) thedistance between the origin of replication and the termination of replication.

e) oneDNA strand of a single chromosome.

Back 150

d) the distance between the origin of replication and the termination of replication.

Front 151

Some bacteria are motile because they have:

a) Pili

b) Fimbriae

c) Flagella

d) Plasmids

e) Capsules

Back 151

c) Flagella

Front 152

When flagella are attached at many sites around the surface of a prokaryotic cell they are called:

a) Lophotrichous

b) Peritrichous

c) Monotrichous

d) Polar

e) Atrichous

Back 152

b) Peritrichous

Front 153

If a bacterium is monotrichous this means:

a) The cell has plasmid

b) The cell can travel in one direction only

c)The cell has one flagellum

d)The cell is not motile

e) The cell is covered in fimbriae

Back 153

c)The cell has one flagellum

Front 154

The presence of motility is demonstrated in the Cragie tube test by:

a) The production of gas bubbles

b) A colour change

c) Growth at the site of inoculation only

d) Growth/Turbidity throughout the medium

e) Growth of single colonies

Back 154

d) Growth/Turbidity throughout the medium

Front 155

What cellular structure possessed by N. gonorrhoeae allows it to adhere to host membranes and cause infection?

a) A capsule

b) Fimbriae

c) Flagella

d) Endotoxin

e) Plasmid

Back 155

b) Fimbriae

Front 156

Which of the following cellular components allows genetic material to be transferred by conjugation?

a) Fimbriae

b) Flagella

c) Cell wall

d) Pili

e) Phages

Back 156

d) Pili

Front 157

You perform a hanging drop motility test on Klebsiella and you see the cells moving around the same spot. This indicates:

a) The bacteria are motile

b) The bacteria are motile but may have come from an old culture

c) The bacteria have short flagella and cannot move far

d)Flagella may have been damaged by shaking the culture too forcefully

e) Brownian motion

Back 157

e) Brownian motion

Front 158

What is Brownian motion?

A) Bacterial motility in the direction of an attractant

b) Bacterial motility away from a repellent

c)Bacterial motility in random directions

d) Refers to the rotating action of flagella

e) Occurs when molecules in a solvent bump into bacterial cells

Back 158

e) Occurs when molecules in a solvent bump into bacterial cells

Front 159

The movement of bacteria in the direction of light is known as:

a) Photosynthesis

b) Phototaxis

c) Brownian motion

d) Chemotaxis

e) Streaming

Back 159

b) Phototaxis

Front 160

The conversion of a spore to a vegetative cell is known as:

a) Germination

b) Vegetation

c) Sporulation

d) Phosphorylation

e) Transformation

Back 160

a) Germination

Front 161

Telomerase iscomposed of

a) proteinonly.

b) proteinand RNA.

c) proteinand DNA.

d) RNAand DNA.

e) proteinand lipid.

Back 161

b) protein and RNA.

Front 162

At the growing endof the DNA chain, DNA polymerase catalyses the formation of a ........ bondbetween nucleotides.

a) hydrogen

b) disulfide

c) glycosidic

d) phosphodiester

e) phosphate

Back 162

d) phosphodiester

Front 163

DNA was shown to be the genetic material by

a) Watson and Crick

b) Hershey and Chase

c) Gierer and Schraam

d) Mirsky and Reis

e) Beadle and tatum

Back 163

b) Hershey and Chase

Front 164

DNA and RNA both contain

a) phosphate

b) ribose

c) guanine

d) both A and C

e) all of the above

Back 164

d) both A and C

Front 165

DNA and RNAmolecules are composed of

a) aminoacids

b) nucleotides

c) phospholipids

d) fattyacids

e) monosaccharides

Back 165

b) nucleotides

Front 166

DNA polymeraseenzyme is capable of adding incoming dNTPs in the following fashion:

a) 5'to 3' only

b) 3'to 5' only

c) both3' to 5' and 5' to 3'

d) fromleft to right only

e) noneof the above

Back 166

a) 5' to 3' only

Front 167

In a molecule ofDNA, hydrogen bonds form between

a) adenineand cytosine

b) guanineand adenine

c) adenineand uracil

d) cytosineand thymine

e) thymineand adenine

Back 167

e) thymine and adenine

Front 168

In a molecule of DNA, hydrogen bonds form between

a) adenine and cytosine

b) guanine and adenine

c) adenine and uracil

d) cytosine and thymine

e) thyminea nd adenine

Back 168

e) thymine and adenine

Front 169

In a molecule of DNA, hydrogen bonds form between

a) adenine and cytosine

b) guanine and adenine

c) adenine and uracil

d) cytosine and thymine

e) thymine and adenine

Back 169

e) thymine and adenine

Front 170

In thebacterium Escherichia coli, DNA replication is

a) unidirectionaland dispersive

b) bidirectionand semiconservative

c) unidirectionaland semiconservative

d) dispersiveand semiconservative

e) bidirectionaland dispersive

Back 170

b) bidirectional and semiconservative

Front 171

In the semiconservativemodel of DNA replication, progeny double helices consist of

a) oneparental DNA strand and one new strand

b) twonew DNA strands

c) twoparental strands

d) oneparental strand and one new RNA strand

e) twonew RNA strands

Back 171

a) one parental DNA strand and one new strand

Front 172

The number ofpurine molecules in a molecule of DNA is ............. to the number ofpyrimidines.

a) greaterthan

b) lessthan

c) equalto

d) exponentiallylarger than

Back 172

c) equal to

Front 173

The pentose sugarin RNA is

a) dextrose

b) ribulosebisphosphate

c) ribose

d) deoxyribose

e) ribulose

Back 173

c) ribose

Front 174

Which DNA base isconsidered a purine?

a) adenine

b) cytosine

c) uracil

d) thymine

e) allof the above

Back 174

a) adenine

Front 175

Which RNA base is apyrimidine?

a) cytosine

b) thymine

c) uracil

d) bothA and C

e) allof the above

Back 175

d) both A and C

Front 176

Five different types of bacteria are exposed to UV radiation for 90 seconds. Which would you expect to survive?

a) A gram-negative cell such as E. coli

b) A gram-positive cell such as Staphylococcus

c) A gram-negative environmental isolate of Serratia

d) A water loving gram-negative isolate of Pseudomonas

e) A spore-forming bacteria such as Bacillus

Back 176

e) A spore-forming bacteria such as Bacillus

Front 177

Mycolic acids prevent Gram stain penetration and are found in the cell walls of:

a) Staphylococcus

b) E. coli

c) Mycobacterium

d) Bacillus

e) Streptococcus

Back 177

c) Mycobacterium

Front 178

Mycobacterium can best be described as:

a) gram-positive bacilli

b) gram-negative bacilli

c) acid-fast bacilli

d) resistant to all stains because their cell wall is full of lipids

e) lacking a cell wall

Back 178

c) acid-fast bacilli

Front 179

The loose unstructured arrangement of glycocalyx around a prokaryotic cell is known as:

a) A slime layer

b) Capsule

c) Peptidoglycan

d) Biofilm

e) Cell wall

Back 179

a) A slime layer

Front 180

Which of the following is not true about biofilms?

a) They grow on surfaces

b) They are associated with nosocomial infections through their growth on medical devices

c) Help bacteria resist host immune system defences

d) They are easily removed by physical forces

e) They protect bacteria from the effect of antibiotics

Back 180

d) They are easily removed by physical forces

Front 181

Which of the following helps to protect a bacterium from phagocytosis by the hosts immune system:

a) Peptidoglycan

b) Capsule

c) Cell membrane

d) Pili

e) Endospores

Back 181

b) Capsule

Front 182

Which of the following is not true regarding bacterial endospores?

a) Produced inside a vegetative cell

b) Consist of several layers

c) Are able to stay dormant for years

d) Contain dipicolinic acid

e) Contain a greater water content then vegetative cells

Back 182

e) Contain a greater water content then vegetative cells

Front 183

Endospores are advantageous to the bacteria because:

a) They increase the pathogenicity of the microorganism

b) They protect microorganisms from being attacked by a hosts immune system

c) They are extremely resistant to heat

d) They allow a microorganism to survive when environmental conditions are not favourable

e) Both (c) and (d) are most correct

Back 183

e) Both (c) and (d) are most correct

Front 184

In a Gram stain you see gram-positive bacilli that contain unstained regions the microorganism. This could be:

a) A capsule around Staphylococcus

b) A capsule around Streptococcus

c) A spore inside Clostridium

d) Slime around E. coli

e) Slime around Pseudomonas

Back 184

c) A spore inside Clostridium

Front 185

What is the function of peptidoglycan in prokaryotic cells:

a) Carbon storage as an energy source

b) Water storage preventing cells from becoming dehydrated

c) A buffer maintaining pH of the cell

d) Adds strength and shape to the cell wall

e) Allows bacteria to float

Back 185

d) Adds strength and shape to the cell wall

Front 186

DNA primase is an enzyme that catalyzes the reactions necessary to synthesize a molecule of:

a) RNA.

b) DNA.

c) protein.

d) lipid.

e) carbohydrate.

Back 186

a) RNA.

Front 187

During replication, the role of DNA primase is to

a) untwist the double helix at the origin of replication.

b) synthesize the primosome.

c) synthesize a short chain of RNA.

d) add nucleotides to the growing DNA chain.

e) relax the supercoiling of the double helix.

Back 187

c) synthesize a short chain of RNA.

Front 188

Distinguish between bacterial structures harboured by most cells from those only in select species

Back 188

Most bacteria have:

Chromosome,

cytoplasmic membrane,

ribosome,

cell wall.

Some bacteria have:

flagellum,

capsule/slime layer,

pili/fimbriae,

endospore

Front 189

Give examples of types of glycocalyx

illustrate by example how bacteria use it

Back 189

1. Capsule/slime layer.

Thecapsule/slime layer enables bacteria to attach to surfaces and to form biofilms

Encapsulated bacteria are more difficult for the immune system to recognise anddestroy

Front 190

Outline the benefits to bacteria and the disadvantages to humans of biofilms

Back 190

1. Biofilm formation allows cells to resist physicalforces of removal,

to resist attack by host immune system,

protects fromthe action of antibiotics

Front 191

During replication, the role of DNA primase is to

a) untwist the double helix at the origin of replication.

b) synthesize the primosome.

c) synthesize a short chain of RNA.

d) add nucleotides to the growing DNA chain.

e) relax the supercoiling of the double helix.

Back 191

c) synthesize a short chain of RNA.

Front 192

Fimbriae

Back 192

-Fimbriae enable bacteria to attach to surfaces such as animal tissues (mucosa of mouth, GIT etc)

and also to form biofilms

Front 193

pili

Back 193

Pili involved in genetic transfer between bacteria via conjugation,

alsothought to be involved in attachment

Front 194

types of bacterial flagella

Back 194

7. -Monotrichous-

Lophotrichousflagella -arranged as a tuft of flagella on one end of the cell

-Polarflagella - attached at one or both ends

-Peritrichousflagella - arranged at many locations around the cell

Front 195

How flagella is involved in movement

Back 195

enabled by flagella rotation (similar to propeller rotation)

-The motor thatrotates the flagellum made up of a rod surrounded by a series of rings

Front 196

Describe two different ways to detect motility

Back 196

7. hangingdrop test

-Fresh cultures of live,unstained bacteria used, so cells will be transparent and more difficult to see

-Semi-solid agar media(e.g. Craigie tube) can be used:

-Motile bacteria willshow diffuse growth through the tube, media will be opaque throughout the tube

-Non-motile bacteria willonly grow at the inoculation point, the rest of the media will remaintransparent

Front 197

Brownian motion

Back 197

not motility,

caused by bacteria colliding withwater molecules

Front 198

Brownian motion

Back 198

not motility,

caused by bacteria colliding with water molecules

Front 199

True motility

Back 199

bacteriawill move in different directions, not all in the same direction

Front 200

endospore

Back 200

-a cell created within the vegetative cell

highly resistant to:

- heat/cold,

-dehydration,

-UV radiation

-chemicals

- Bacterial endospores can remain dormant for many years

Front 201

vegetative cell

Back 201

Bacterial cell which produces endospores

Front 202

List some features of endospores

Back 202

7. can remain dormant for many years,

-

don’t stain with basic microbiological dyes

- A mature endospore contains 10-25% of the water content of a vegetative cell,

-cytoplasm forms a gel which, helps in heat resistance -

-Spores are activated e.g. by heat, will germinate rapidly in presence of certain nutrients, outgrow to form vegetative cells

Front 203

Explain why we use an acid-fast stain to microscopically see Mycobacteria spp.

Back 203

surfacelipids of mycolic acid are not readily gram-stained

Front 204

What genus of pathogenic bacteria often appear asgram-positive cocci:

in clusters?

In chains?

Back 204

Clusters – staphylococci

Chains – Streptococci

Front 205

What is the most common error that occurs whenselecting a colony for subculture?

Back 205

A mixture of colonies is selected

not a pure culture

Front 206

How can you tell gram-positive from gram-negative organisms?

Back 206

Gram positive stain purple

Gram negative stain pink

Front 207

Explain why we use an acid-fast stain to microscopically see Mycobacteria spp.

Back 207

surfacelipids of mycolic acid are not readily gram-stained

Front 208

How can capsules be seen microscopically?

Back 208

Capsules do not stain

can sometimes be seen as clear area in a stain

Front 209

What is the most common error that occurs when selecting a colony for subculture?

Back 209

A mixture of colonies is selected

not a pure culture

Front 210

What is the purpose of iodine in the Gram stain?

Back 210

1. Fixing the first stain

Front 211

How can spores be distinguished from vegetative forms of bacteria?

Back 211

Spores are more resistant to taking up aqueous stains.

Canbe found inside vegetative cells

Front 212

List the order of stains used in the Gram stain(the red stain can be simply called a counter-stain as various red/pink dyes can beused).

Back 212

Stain, iodine, acetone, counterstain

Front 213

Why do we need to wait until the gram-stained smear is completely dry?

Back 213

so that the oil canbe added for viewing under the microscope

Front 214

Why is it important to separate mixed culture to pure cultures?

Back 214

Pure culture is important to study the characteristics of the organism of interest.

Front 215

Garrod’s study on ‘inborn errors of metabolism’

Back 215

studied people whose urine turned black on exposure to air alkaptonuria)

-found that it is genetically inherited disease

-postulated that symptoms were a reflection of the individuals inability to make a particular enzyme

-a normal person has an enzyme which breaks down alkapton (homogentisic acid)

- alkaptonuric individuals lack the enzyme

-first to suggest that genes dictate phenotype through enzymes

Front 216

Beadle and Tatum’s experiment with Neurospora

Back 216

•treated conidia with X-rays (mutagen)

•crossed the conidia with prototrophic strain of opposite mating type

•this ensured genetic basis of inheritance

•one ascospore per cross was cultured on complete media sub-cultured into different tubes

•strains that grew only when supplemented with amino acids were sub-cultured into different tubes supplemented with individual amino acids

•thus, strains that were mutants for particular amino acids were identified

Front 217

One gene-One enzyme hypothesis

Back 217

function of the gene was to dictate production of a specific enzyme

Front 218

5. Phenylketonuria (PKU)

Back 218

–1/12,000 Caucasian births

–Mutation in Phenylalanine hydroxlase gene –Prevents conversion of Phe to Tyr

–Phe accumulates and converted to phenylpyruvic acid

–Pleiotropic effects: no thyroxine, adrenaline, melanin

–Can be managed with dietary restrictions

Front 219

Phe

Back 219

Phenylalanine

Front 220

Beadle and Tatum’s experiment with Neurospora

Back 220

•treated conidia with X-rays (mutagen)

•crossed the conidia with prototrophic strain of opposite mating type

•this ensured genetic basis of inheritance

•one ascospore per cross was cultured on complete media sub-cultured into different tubes

•strains that grew only when supplemented with amino acids were sub-cultured into different tubes supplemented with individual amino acids

•thus, strains that were mutants for particular amino acids were identified

Front 221

Lesch-Nyhan syndrome

Back 221

•Fatalrecessive human trait

•1/10,000males

•Deficiencyin hypoxanthine-guanine phosphoribosyltransferase

–Purinesaccumulate and convert to uric acid

•Severeneurological symptoms

Front 222

Tay-Sachs Disease

Back 222

•Rare in general population but more frequent in Ashkenazi Jews –1/3,600

•Gene defect in Lysosomal enzyme

•hexA encodes N-acetylhexosaminidase A - Cleaves group from brain ganglioside GM2

•Symptoms – reaction to sharp sounds & cherry-coloured spot on the retina, loss of mobility, early death

Front 223

Sickle-Cell anemia

Back 223

•Recessive mutation

•Hemoglobin transports oxygen in blood

•Mutation in gene that produces polypeptide of hemoglobin

•Hemoglobin different to normal

•Red blood cells change shape–sickled shape

•Sickle-cell trait–Less severe form of the disease

Front 224

Cystic fibrosis

Back 224

•Most common lethal disease among Caucasians –1/2000 newborns–1/23 are carriers

•Causes pancreatic, pulmonary and digestive dysfunction –High viscosity mucus

•cystic fibrosis transmembrane conductance regulator (CFTR) –1,480 amino acid long membrane protein

•serves as Chloride channel –Deletion of 3 bases – one amino acid missing –∆F508

Front 225

Alterations in genes do what to proteins

Back 225

can result in alteration in proteins.

Front 226

Sickle-Cell anemia

Back 226

•Recessive mutation

•Mutation in gene that produces polypeptide of hemoglobin

•Red blood cells change shape–sickled shape

•Sickle-cell trait–Less severe form of the disease

Front 227

Streak dilution isused to isolate strains of bacteria. This means

a) tubesof agar are stabbed and organisms are grown

b) bacteriaare isolated by double-dilution using a series of test tubes

c) bacteriaare spread over the surface of agar plates so that single colonies are obtained

d) brothcultures are used to grow bacteria

e) biochemicaltests are used to isolate bacteria

Back 227

c) bacteria are spread over the surface of agar plates so that single colonies are obtained

Front 228

In order todetermine whether a culture is mixed, the most important step would be to

a) lookat a microscopic preparation

b) seeif there was evidence of different colony morphologies on agar

c) testto see the antibiotic susceptibilities

d) runbiochemical tests on the predominant strain

e) usedifferent stains to see if reactions were different

Back 228

b) see if there was evidence of different colony morphologies on agar

Front 229

In order to determine whether a culture is mixed, the most important step would be to

a) look at a microscopic preparation

b) see if there was evidence of different colony morphologies on agar

c) test to see the antibiotic susceptibilities

d) run biochemical tests on the predominant strain

e) use different stains to see if reactions were different

Back 229

b) see if there was evidence of different colony morphologies on agar

Front 230

When viewed under oil-immersion,bacterial width appears to the eye on average around how many millimetres wide?

a) 0.5

b) 1

c) 1.5

d) 2

e) 5

Back 230

b) 1

Front 231

To determine if aplate culture of bacteria is pure you need to see if

a) thereare different sizes of bacteria down the microscope

b) thereare different shapes of bacteria down the microscope

c) thereare different gram-stained bacteria down the microscope

d) colonieshave different sizes on the agar

e) anydifferent colony types are on the agar

Back 231

e) any different colony types are on the agar

Front 232

Streak dilution is used to isolate strains of bacteria. This means

a) tubes of agar are stabbed and organisms are grown

b) bacteria are isolated by double-dilution using a series of test tubes

c) bacteria are spread over the surface of agar plates so that single colonies are obtained

d) broth cultures are used to grow bacteria

e) biochemical tests are used to isolate bacteria

Back 232

c) bacteria are spread over the surface of agar plates so that single colonies are obtained

Front 233

To determine if a plate culture of bacteria is pure you need to see if

a) there are different sizes of bacteria down the microscope

b) there are different shapes of bacteria down the microscope

c) there are different gram-stained bacteria down the microscope

d) colonies have different sizes on the agar

e) any different colony types are on the agar

Back 233

e) any different colony types are on the agar

Front 234

What genus ofpathogenic bacteria often appear as gram-positive cocci in clusters?

a) Staphylococcus

b) Streptococcus

c) Bacillus

d) Escherichia

e) Noneof the above

Back 234

a) Staphylococcus

Front 235

What is the most common error that occurs when selecting a colony for subculture?

a) failure to use aseptic technique

b) failure to flame loop

c) failure to cool loop

d) touching more than one colony

e) selecting wrong agar for subculture

Back 235

d) touching more than one colony

Front 236

How can you tell gram-positive from gram-negative organisms?

a) gram-positiveare purple while gram-negative are pink

b) gram-positiveare in clusters while gram-negative are in chains

c) gram-positive are pink while gram-negative are yellow

d) gram-positive are motile while gram-negative are not

e) gram-positive have spores while gram-negative have not

Back 236

a) gram-positive are purple while gram-negative are pink

Front 237

How can spores be distinguished from vegetative forms of bacteria?

a) spores are always gram-positive

b) spores are always gram-negative

c) spores are non-motile while vegetative bacteria are always motile

d) spores do not stain with Gram stain while vegetative bacteria do

e) spores are always larger than bacterial cells

Back 237

d) spores do not stain with Gram stain while vegetative bacteria do

Front 238

An organism has acapsule so that it can

a) makespores

b) bemotile

c) growon agar plates

d) remaindormant in the environment

e) resistthe human immune system

Back 238

e) resist the human immune system

Front 239

The word'counter-stain' means in reference to the Gram stain

a) Theiodine that is added to help bind the crystal violet

b) Thered stain used to show bacteria that have lost the crystal violet stain

c) Theacetone that is used to take away the crystal violet

d) Thecrystal violet used to make the cells gram-positive

e) Noneof the above

Back 239

b) The red stain used to show bacteria that have lost the crystal violetstain

Front 240

An organism has a capsule so that it can

a) make spores

b) be motile

c) grow on agar plates

d) remain dormant in the environment

e) resist the human immune system

Back 240

e) resist the human immune system

Front 241

What genus of pathogenic bacteria often appear as gram-positive cocci in clusters?

a) Staphylococcus

b) Streptococcus

c) Bacillus

d) Escherichia

e) None of the above

Back 241

a) Staphylococcus

Front 242

Which is the correct order of stains used in the Gram stain?

a) crystal violet, iodine, acetone, counterstain

b) iodine, crystal violet, acetone, counterstain

c) crystal violet, counterstain, acetone, iodine

d) acetone, crystal violet, iodine, counterstain

e) counterstain, crystal violet, acetone, iodine

Back 242

a) crystal violet, iodine, acetone, counterstain

Front 243

Why do we need to wait until the gram-stained smear is completely dry?

a) so that the crystal violet has set into the cells

b) so that the iodine has had time to kill the bacteria

c) so that the counterstain has time to develop

d) so that the oil can be added for viewing under the microscope

e) so that the bacteria don t float away

Back 243

d) so that the oil can be added for viewing under the microscope

Front 244

Which of thefollowing is an example of poor aseptic technique?

(a) incubatingcultures with the Petri lid dish uppermost

(b) failingto obtain single colonies on streak dilution

(c) failingto set the microscope up to maximise resolution

(d) notwashing hands before leaving the laboratory

(e) holdinga broth tube vertically while inoculating

Back 244

(e) holding a broth tube vertically while

Front 245

Which of the following additives do not need tobe sterilised before adding to agar?

(a) blood

(b) peptone

(c) agar

(d) carbohydrate

(e) yeast extract

Back 245

(a) blood

Front 246

The best description of an aminoacid is that it is a:

(a) peptide

(b) protein

(c) monomer

(d) monosaccharide

(e) complex medium

Back 246

(c) monomer

Front 247

A suitable carbon source forculturing microbes is:

(a) carbon monoxide

(b) carbon dioxide

(c) methane (CH4)

(d) peptone

(e) an amino acid

Back 247

(d) peptone

Front 248

Asuitable nitrogen source for a microbe is:

(a) peptone

(b) glucose

(c) alcohol

(d) acetone

(e) maltose

Back 248

(a) peptone

Front 249

Peptonesare:

(a) derived from a defined mixture ofmonomers

(b) either animal or vegetable in origin

(c) can only be animal in origin

(d) a synthetic defined media

(e) a complex defined media

Back 249

(b) either animal or vegetable in origin

Front 250

Minimal media would most likely to consist of:

(a) agar and water only

(b) agar, water and salts only

(c) agar, water, salts and a defined carbohydrate/nitrogen source

(d) agar, water and peptone only

(e) agar, water and yeast extract only

Back 250

(c) agar, water, salts and a defined carbohydrate/nitrogen source

Front 251

Pinpoint growth of bacteria growing on a solid surface could be called:

(a) a coccus

(b) cocci

(c) tissue

(d) a collection

(e) colonies

Back 251

(e) colonies

Front 252

One of the first solid media for growing bacteriawas:

(a) potato slices

(b) seaweed

(c) jelly

(d) butter

(e) glass

Back 252

(a) potato slices

Front 253

The source of agar is:

(a) potato

(b) yeast

(c) peptone

(d) seaweed

(e) blood

Back 253

(d) seaweed

Front 254

A suitable carbon source for culturing microbes is:

(a) carbon monoxide

(b) carbon dioxide

(c) methane (CH4)

(d) peptone

(e) an amino acid

Back 254

(d) peptone

Front 255

To prepareblood agar you must:

(a) mix blood and agar then filter sterilise

(b) add agar after sterilising the blood

(c) add blood at room temperature to agar at45C

(d) addblood warmed to 45C to agar at 45C

(e) heat blood until it goes a chocolatecolour

Back 255

(d) addblood warmed to 45C to agar at 45C

Front 256

Peptones are:

(a) derived from a defined mixture of monomers

(b) either animal or vegetable in origin

(c) can only be animal in origin

(d) a synthetic defined media

(e) a complex defined media

Back 256

(b) either animal or vegetable in origin

Front 257

A student finds that the agar culture has heavy growth of bacteria but no individual streak lines. This may have resulted from:

(a) too many bacteria in the original sample

(b) not flaming the loop between streaking

(c) the plate being incubated upside down and condensation making colonies run

(d) an impure culture

(e) not cooling the loop before streaking

Back 257

(c) the plate being incubated upside down and condensation making colonies run

Front 258

Streak dilution should result in:

(a) less colonies of bacteria on the agarplate

(b) more colonies of bacteria on the agarplate

(c) single colonies on part of the agar plate

(d) heavy growth of bacteria on the agarplate

(e) even growth of bacteria spread all overthe agar plate

Back 258

(c) single colonies on part of the agar plate

Front 259

An agar plate labelled CHA wouldbe useful to grow:

(a) bacteria contaminating carbohydrates suchas chocolate

(b) bacteria contaminating dairy products such as cheese

(c) bacteriarequiring nutrients found inside red blood cells

(d) bacteriathat require a defined medium

(e) bacteriathat require extra carbohydrates

Back 259

(c) bacteria requiring nutrients found inside red blood cells

Front 260

Enrichment broth may be used to isolate Salmonella. This is because Salmonella:

(a) require a complex medium

(b) require a defined medium

(c) may be difficult to isolate when E. coli is present

(d) require blood for growth

(e) grow in broth rather than solid medium

Back 260

(c) may be difficult to isolate when E. coli is present

Front 261

MacConkey agar acts as differential medium because

(a) bacteria will appear as fermentors or non-fermentors

(b) it will change the appearance of bacteria if motile

(c) not all colonies are haemolytic

(d) some bacteria will produce pigment on this agar

(e) only some bacteria will grow on it

Back 261

(a) bacteria will appear as fermentors or non-fermentors

Front 262

HBA is best described as

(a) a differential medium when growinghaemolytic and non-haemolytic bacteria

(b) an enrichment medium because more bacteria will grow on it

(c) an enriched medium because it will grow all bacteria

(d) a complex medium because it is notpossible to sterilise blood

(e) a defined medium because blood is thedefined ingredient

Back 262

(a) a differential medium when growing haemolytic and non-haemolytic bacteria

Front 263

MCA can also be used as a selective medium because it contains

(a) blood that will grow select organisms

(b) bile salts that favours the growth of some gram-negative bacteria

(c) carbohydrates that will be selective for fermentors or non-fermentors

(d) pH indicator that will distinguish fermentors from non-fermentors

(e) amino acids that favour the growth of gram-positive organisms

Back 263

(b) bile salts that favours the growth of some gram-negative bacteria

Front 264

List some heat sensitive culture media additives

Back 264

blood

vitamins

antibiotics

Front 265

Name some suitable carbon and nitrogen sources for complex media

Back 265

Carbon often supplied in culture media using glucose, or using more complex mixtures e.g. peptone, yeast extract

Nitrogen often supplied in culture media using amino acids, or more complex mixtures such as peptone

Front 266

List some typical ingredients for a defined growth medium such as minimal media

Back 266

glucose as carbon source,

ammonium phosphate asnitrogen source,

trace elements

Front 267

Define the term ‘colony’ of bacteria

Back 267

as cells divide on solid media they pile up inone area, forming a colony

Front 268

Define the term ‘colony’ of bacteria

Back 268

as cells divide on solid media they pile up in one area, forming a colony

Front 269

Limitations of potato slices as solid media

Back 269

only some bacteria would grow on potato,

frequent fungal contamination

Front 270

Limitations of gelatin as solid media

Back 270

wouldn’t remain solid at 37°C – the optimal growthtemp. for most human pathogens

Front 271

Name the source of agar

Back 271

red algae

Front 272

list the properties of agar

Back 272

polysaccharide

-it remains solid at 37°C

-after boiling it remains liquid untilcooled to about 45°C

Front 273

State the best temperature to warm blood and agar before mixing

Back 273

addblood warmed to 45oC to agar at 45oC

Front 274

State the best temperature to warm blood and agar before mixing

Back 274

add blood warmed to 45oC to agar at 45oC

Front 275

Nutrient Agar

Back 275

NA – Solid media - same recipe as nutrient broth + agar

Front 276

Horse Blood Agar

Back 276

HBA– Solid media - nutrient agar with bloodadded, some organisms require nutrients found in blood

Front 277

Chocolate Agar

Back 277

CHA – Solid media - nutrient agar with heatedblood added

Front 278

Distinguish the characteristics of growth media termed enriched, enrichment and differential

Back 278

Enriched media – basal media with extra nutrients added, e.g. horse blood agar -

Enrichment media – used to assist the growth of target organism in a mixed culture -contains additives which inhibit the growth of non-target organisms and improve the growth of target organisms

-Differential/indicator media – contains substances which produce visible difference between organisms with different metabolisms -Used to visually identify target organisms growing in a mixed culture on solid media

Front 279

Enriched media

Back 279

basal media with extra nutrients added, e.g.horse blood agar

Front 280

Enrichment media

Back 280

used to assist the growth of target organism in a mixed culture

-contains additives which inhibit the growth of non-target organisms and improve the growth of target

Front 281

Differential/ indicator media

Back 281

contains substances which produce visible difference between organisms with different metabolisms -

Used to visually identify target organisms growing in a mixed culture on solid media

Front 282

Selective media

Back 282

1. Selective media will restrict the growth of non-target organisms,

may improve the growth of target orgs

Front 283

MacConkey agar (MCA)

Back 283

MacConkey agar (MCA) is a selective media as well as a differential media

-Contains bile salts, which inhibit the growth of many microorganisms

-The neutral red indicator in MCA differentiates between lactose fermenters/nonfermenters

– red when acidic, yellow when basic

Front 284

Name some basal ingredients of media that are monomers

Back 284

-amino acids in the case of proteins,

-sugars inthe case of polysaccharides,

-nucleotides in the case of DNA and RNA

Front 285

Describe what is meant by ‘peptone’

Back 285

A mixture of peptides.

Meat or milk boiled, its longproteins are broken down into peptides.

Front 286

What is an organic compound

Back 286

complexmolecules that are required by organisms to convert to energy

Front 287

What is the maximum growth temperature of a organism?

a) The temperature at which a organism grows the best

b) The temperature at which cell division occurs most rapidly

c) That temperature at which cell division slows down

d) A temperature that if exceeded will inhibit growth

e) A temperature greater than which, growth will cease

Back 287

e) A temperature greater than which, growth will cease

Front 288

Why do some cells stop growing when the temperature is too cold?

a) The cell membrane loses its fluidity

b)Proteins become denatured

c) Cells become dehydrated

d) Enzymes become more active

e) The cell membrane becomes overly fluid

Back 288

a) The cell membrane loses its fluidity

Front 289

Microorganisms that cause disease in humans can be classed as:

a) Psychrophiles

b) Psychrotrophs

c) Mesophiles

d) Thermophiles

e) Hyperthermophiles

Back 289

c) Mesophiles

Front 290

Bacteria that cause spoilage of refrigerated foods are called:

a) Psychrotrophs

b) Mesophiles

c) Thermophiles

d) Hyperthermophiles

e) Xerophiles

Back 290

a) Psychrotrophs

Front 291

Where are you most likely to find a thermophile?

a) In the soil

b) In animal intestines

c) In cooked food

d) A swimming pool

e) In a bath tub

Back 291

a) In the soil

Front 292

Which of the following growth temperature range might be that of a mesophile?

a) 0 C – 4 C

b) 0 C – 20 C

c) 20 C – 45 C

d) 45 C – 65 C

e) 65 C – 110 C

Back 292

c) 20 C – 45 C

Front 293

The stomach is not a favourable environment for bacterial colonization due to:

a. High acidity

b. High pH

c. Lack of receptors on the mucosa for bacteria to attach

d. Lack of moisture

e. The shape of the stomach

Back 293

a. High acidity

Front 294

Bacillus cereus is often the cause of food poisoning associated with rice because:

a) Bacillus cereus grows best at cold refrigeration temperatures

b) Bacillus cereus grows best at high cooking temperatures

c) Bacillus cereus contains endotoxin in its cell wall that is resistant to heat

d) When rice is cooled slowly after cooking Bacillus cereus grows rapidly in the rice

e)Vegetative cells are extremely resistant to heat

Back 294

d) When rice is cooled slowly after cooking Bacillus cereus grows rapidly in the rice

Front 295

What temperature should hot foods be kept at to prevent food borne disease?

a) 4°C – 20°C

b) 20°C – 30°C

c) 30°C – 40°C

d) 40°C – 50°C

e) Greater than 60°C

Back 295

e) Greater than 60°C

Front 296

Microorganisms that require oxygen to grow are called:

a) Obligate aerobes

b) Obligate anaerobes

c) Facultative anaerobes

d) Aerotolerant anaerobes

d) Microaerophiles

Back 296

a) Obligate aerobes

Front 297

Which of the following is an example of a strict aerobe?

a) E. coli

b) Pseudomonas aeruginosa

c) Serratia marcescens

d) Staphylococcus aureus

e) Clostridium perfringens

Back 297

b) Pseudomonas aeruginosa

Front 298

What is a facultative anaerobe?

a) A microbe that needs oxygen to grow

b) A microbe that only grows in the absence of oxygen

c) A microbe that grows optimally in oxygen but can grow in its absence

d) A microbe that can survive in oxygen but grows anaerobically

e) A microbe that grows only in a small amount of oxygen

Back 298

c) A microbe that grows optimally in oxygen but can grow in its absence

Front 299

Which of the following bacteria can grow anaerobically:

a) E. coli

b) Clostridium perfringens

c) Staphylococcus aureus

d) Streptococcus pyogenes

e) All of the above

Back 299

e) All of the above

Front 300

In prac you inoculate a tube of Brewers Thioglycollate medium with Bacteroides fragilis. Following incubation what should you see?

a) Growth only at the top of the tube

b) Growth only at the bottom of the tube

c) Even growth throughout the tube

d) Growth throughout the tube that is heavier towards the top

e) No growth anywhere in the tube

Back 300

b) Growth only at the bottom of the tube

Front 301

Which of the following is an example of a microaerophilic microorganism?

a) Bacteroides fragilis

b) Clostridium perfringens

c) Pseudomonas aeruginosa

d) E. coli

e) Campylobacter jejuni

Back 301

e) Campylobacter jejuni

Front 302

A microorganism that requires sodium chloride to grow is called a:

a) Neutrophiles

b) Alkalophiles

c)Acidophiles

d) Osmophiles

e) Halophiles

Back 302

e) Halophiles

Front 303

A jar of jam is most likely to be spoiled by mould because:

a) Jam has a low water activity

b) Jam has a high water activity

c) Jam has a high pH

d) Jam has a low pH

e) Moulds grow more rapidly than bacteria

Back 303

a) Jam has a low water activity

Front 304

When growing bacteria release acids into culture media the pH is stabilised by:

a) Reducing agents

b) Growth factors

c) Antibiotics

d) Buffers

e) Differential dyes

Back 304

d) Buffers

Front 305

What is meant by bacterial generation time?

a) The time it takes for DNA to replicate

b) The time taken for bacteria to start growing on an agar plate

c) The time it takes for a microbe to reach its optimal growth rate

d) The time taken for bacteria to use all the nutrients in a medium

e) The doubling time for a group of cells

Back 305

e) The doubling time for a group of cells

Front 306

Where would you find psychrophiles

Back 306

Growmostly in the ocean depths or in certain polar regions,

Front 307

Where would you would find psychrotrophs

Back 307

foodsimproperly stored as they are more common in the environment

Front 308

Where would you find mesophiles

Back 308

moderatetemperature, neither too hot nor too cold, typically between 20 and 45 °C

Front 309

Where would you would find psychrotrophs

Back 309

foods improperly stored as they are more common in the environment

Front 310

List the reasons that temperature affects growth of bacteria

Back 310

At low temperatures

-the cell membrane loses fluidity

- enzymes stop working

- transport in/out goes very slowly

-Growth cannot occur

At temperatures above the optimum

- proteins denature

- ribosomal RNA denatures

- cell membrane becomes too fluid

-Cells cannot continue to grow

Front 311

State the pH growth range for most microbes

Back 311

Most bacteria grow best in a narrow pH between6.5 and 7.5

Front 312

Where would you find psychrophiles

Back 312

Growmostly in the ocean depths or in certain polar regions,

Front 313

Where would you find psychrophiles

Back 313

Grow mostly in the ocean depths or in certain polar regions,

Front 314

Where would you find mesophiles

Back 314

moderatetemperature, neither too hot nor too cold, typically between 20 and 45 °C

Front 315

Where would you find thermophilic

Back 315

-hot water,

-sun lit soils and thermal springs.

-Also important in compost heaps were temps can get to 50 – 60.

-Endospores of thermophilic bacteria may survive canning processes.

Front 316

Where would you find Hyperthermophiles

Back 316

Hotundersea volcanic vents

Front 317

Explain and state the temperature chosen to keep foods warm

Back 317

Above 65 C. Very few disease causing bacteria can grow above 65 C

Front 318

Describe why rice salad has frequently been responsible for food poisoning

Back 318

Whenrice is cooled slowly after cooking Bacilluscereus grows rapidly in the rice

Front 319

List the reasons that temperature affects growth of bacteria

Back 319

At low temperatures

-the cell membrane loses fluidity

- enzymes stop working

- transport in/out goes very slowly

-Growth cannot occur

At temperatures above the optimum

- proteins denature

- ribosomal RNA denatures

- cell membrane becomes too fluid

-Cells cannot continue to grow

Front 320

Give an example of an acidophil and why it is used in foods

Back 320

Lactobacillus.

In yoghurt.

Ferments milk sugars and produces an acid product.

Acid from fermentation prevents harmful bacteria growing.

Front 321

State the pH growth range for most microbes

Back 321

Mostbacteria grow best in a narrow pH between 6.5 and 7.5

Front 322

The study of whichgenetic disease led Garrod to propose that there is a special relationshipbetween genes and enzymes?

a) Tay-Sachsdisease

b) sicklecell disease

c) phenylketonuria

d) alkaptonuria

Back 322

d) alkaptonuria

Front 323

The one gene-oneenzyme hypothesis was proposed by ___ in 1942.

a) Beadleand Tatum

b) Meselsonand Stahl

c) Garrod

d) Morgan

Back 323

a) Beadle and Tatum

Front 324

The study of which genetic disease led Garrod to propose that there is a special relationship between genes and enzymes?

a) Tay-Sachs disease

b) sicklecell disease

c) phenylketonuria

d) alkaptonuria

Back 324

d) alkaptonuria

Front 325

Mutant strains of abacterium that are unable to grow on a minimal medium are ____________________.

a) prototrophic.

b) autotrophic.

c) auxotrophic.

d) phototrophic.

Back 325

c) auxotrophic.

Front 326

A methionine auxotroph ____________________.

a) can not grow on a complete medium.

b) can grow on minimal medium supplemented with methionine.

c) can not grow in the presence of methionine.

d) can grow on minimal medium with no supplements.

Back 326

b) can grow on minimal medium supplemented with methionine.

Front 327

Mutant strains of a bacterium that are unable to grow on a minimal medium are ____________________.

a) prototrophic.

b) autotrophic.

c) auxotrophic.

d) phototrophic.

Back 327

c) auxotrophic.

Front 328

In PKU, the absence of enzyme activity effects which step in the phenylalanine metabolism pathway?

a) conversion of phenylalanine to tyrosine

b) conversion of phenylalanine to phenylpyruvic acid

c) conversion of tyrosine to melanin

d) conversion of phenylpyruvic acid to melanin

Back 328

a) conversion of phenylalanine to tyrosine

Front 329

The Guthrie test for PKU requires the use of which microorganism?

a) Saccharomyces cerevisiae

b) Escherichia coli

c) Neurospora crassa

d) Bacillus subtilis

Back 329

d) Bacillus subtilis

Front 330

The one gene-one enzyme hypothesis was proposed by ___ in 1942.

a) Beadle and Tatum

b) Meselson and Stahl

c) Garrod

d) Morgan

Back 330

a) Beadle and Tatum

Front 331

The normal versionof the mutant gene responsible for albinism in humans encodes an enzyme thatconverts ____________________.

a) phenylalanineto DOPA.

b) DOPAto melanin.

c) phenylalanineto tyrosine.

d) tyrosineto DOPA.

Back 331

d) tyrosine to DOPA.

Front 332

The mutant gene responsible for PKU is located on ____________________.

a) the X chromosome.

b) chromosome 12.

c) chromosome 1.

d) chromosome 21

Back 332

b) chromosome 12.

Front 333

Which disease is caused by a mutation in a gene located on the X chromosome?

a) PKU

b) Tay-Sachs disease

c) Lesch-Nyhan syndrome

d) albinism

Back 333

c) Lesch-Nyhan syndrome

Front 334

The most severeform of Lesch-Nyhan syndrome affects ____________________.

a) femalesonly

b) moremales than females

c) malesonly

d) morefemales than males

Back 334

b) more males than females

Front 335

Which of thefollowing is characterized as a lysosomal storage disease?

a) sicklecell anemia

b) PKU

c) cysticfibrosis

d) Tay-Sachsdisease

Back 335

d) Tay-Sachs disease

Front 336

The mutant generesponsible for Tay Sachs disease is located on ____________________.

a) chromosome3.

b) theX chromosome.

c) chromosome10. d) chromosome15.

Back 336

d) chromosome 15.

Front 337

The mutant gene responsible for Tay Sachs disease is located on ____________________.

a) chromosome 3.

b) the X chromosome.

c) chromosome 10.

d) chromosome 15.

Back 337

d) chromosome 15.

Front 338

The most severe form of Lesch-Nyhan syndrome affects ____________________.

a) females only

b) more males than females

c) males only

d) more females than males

Back 338

b) more males than females

Front 339

Which of the following is characterized as a lysosomal storage disease?

a) sickle cell anemia

b) PKU

c) cystic fibrosis

d) Tay-Sachs disease

Back 339

d) Tay-Sachs disease

Front 340

A child born to a man and a woman who are both carriers of the mutant allele responsible for cystic fibrosis has a ___ chance of having the disease.

a) 0%

b) 25%

c) 50%

d) 100%

Back 340

b) 25%

Front 341

The NobelPrize-winning researchers who are credited with determining that one enzyme isproduced from one gene are

a) Watsonand Crick.

b) Beadleand Tatum.

c) Hersheyand Chase.

d) Garrodand Bateson.

e) Avery,MacLeod, and McCarty.

Back 341

b) Beadle and Tatum.

Front 342

The following is a representation of a metabolic pathway involving genes X, Y, Z and W for enzymes that convert substances A to B, B to C, C to D and D to the final product

A mutation in the "X" gene would result in an accumulation of which gene product?

a) C, D, and the product

b) B only

c) A only

d) A, B, and C

e) the product only

Back 342

c) A only

Front 343

A mutation in thegene for which enzyme is responsible for the metabolic disorderphenylketonuria?

a) adenosinedeaminase

b) phenylalaninehydroxylase

c) acidphosphatase

d) glucose-6-phosphatedehydrogenase

e) noneof the above

Back 343

b) phenylalanine hydroxylase

Front 344

The Nobel Prize-winning researchers who are credited with determining that one enzyme is produced from one gene are

a) Watson and Crick.

b) Beadle and Tatum.

c) Hershey and Chase.

d) Garrod and Bateson.

e) Avery, MacLeod, and McCarty.

Back 344

b) Beadle and Tatum.

Front 345

Bottles of Diet Coke carry a warning for people with PKU because the sweetener used in this drink contains

a) dextroseand fructose.

b) phenylalaninehydroxylase.

c) tyrosine.

d) phenylalanine.

e) saccharine.

Back 345

d) phenylalanine.

Front 346

Which of thefollowing human diseases is caused by an autosomal recessive mutation?

a) alkaptonuria

b) phenylketonuria

c) albinism

d) cysticfibrosis

e) allof the above

Back 346

e) all of the above

Front 347

Lesch-Nyhansyndrome is caused by a mutation in a gene located on which chromosome?

a) 1

b) 16

c) 21

d) X

e) Y

Back 347

d) X

Front 348

The compulsive self-mutilation behaviors exhibited by Lesch-Nyhan individuals are the result of a mutation in the gene for which enzyme?

a) hypoxanthine guanine phosphoribosyltransferase

b) hexosaminidase A

c) para-hydroxypheynlpyruvate oxidase

d) pyruvate kinase

e) phenylalanine hydroxylase

Back 348

a) hypoxanthine guanine phosphoribosyltransferase

Front 349

Tay-Sachs disease is most prevalent in which population?

a) Pennsylvania Amish

b) Ashkenazi Jews of central European descent

c) African and African-American blacks

d) Caucasians of northern European descent

e) Caucasians of Sicilian descent.

Back 349

b) Ashkenazi Jews of central European descent

Front 350

In people who do not have Tay-Sachs disease, the hexA gene encodes an enzyme that

a) converts purines to uric acid in the kidneys.

b) removes a sugar group from phenylalanine.

c) converts tyrosine into melanin in skin.

d) cleaves acetylgalactosamine from gangliosides.

e) synthesizes glycogen from glucose monomers.

Back 350

d) cleaves acetylgalactosamine from gangliosides.

Front 351

Which of the following is characterized as a liposomal storage disease?

a) Lesch-Nyhan syndrome

b) Tay-Sachs disease

c) sickle-cell disease

d) xeroderma pigmentosum

e) all of the above

Back 351

b) Tay-Sachs disease

Front 352

In people who do not have Tay-Sachs disease, the hexA gene encodes an enzyme that

a) converts purines to uric acid in the kidneys.

b) removes a sugar group from phenylalanine.

c) converts tyrosine into melanin in skin.

d) cleaves acetylgalactosamine from gangliosides.

e) synthesizes glycogen from glucose monomers.

Back 352

d) cleaves acetylgalactosamine from gangliosides.

Front 353

A person withsickle-cell trait has ________ at the beta-globin gene locus.

a) twowild-type alleles

b) twomutant alleles

c) onewild-type and one mutant allele

d) onewild-type and one deleted allele

e) onemutant and one deleted allele

Back 353

c) one wild-type and one mutant allele

Front 354

It is possible to distinguish between normal hemoglobin and hemoglobin S using electrophoresis because these two forms of hemoglobin have different

a) molecular weights.

b) electrical charges.

c) densities.

d) masses.

e) all of the above

Back 354

a) molecular weights.

Front 355

The mutationresponsible for sickle-cell disease is a(n)

a) inversioninvolving separate regions of the beta-globin gene.

b) pointmutation in the beta-globin gene.

c) areciprocal translocation involving the alpha- and beta-globin genes.

d) adeletion of part of the beta-globin gene.

e) allof the above

Back 355

b) point mutation in the beta-globin gene.

Front 356

The mutation that changes normal hemoglobin to hemoglobin S changes a codon for glutamic acid to one for

a) alanine.

b) valine.

c) glycine.

d) tyrosine.

e) aspartic acid.

Back 356

b) valine.

Front 357

Among Caucasians, the most common lethal autosomal recessive disease is

a) sickle-cell disease.

b) hemophilia.

c) muscular dystrophy.

d) cystic fibrosis.

e) phenylketonuria.

Back 357

d) cystic fibrosis.

Front 358

The genes for hemoglobin S and hemoglobin A are

a) recessive.

b) codominant.

c) completely dominant.

d) heterozygous.

e)heterogenous.

Back 358

b) codominant.

Front 359

Cystic fibrosis is caused by a mutation in the gene that encodes which enzyme?

a) pyruvate kinase

b) hexosaminidase A

c) CFTR protein

d) hemoglobin

e) tyrosine kinase

Back 359

c) CFTR protein

Front 360

A person with sickle-cell trait has ________ at the beta-globin gene locus.

a) two wild-type alleles

b) two mutant alleles

c) one wild type and one mutant allele

d) one wild-type and one deleted allele

e) one mutant and one deleted allele

Back 360

c) one wild-type and one mutant allele

Front 361

Amniocentesis isbest performed

a) beforethe end of the first trimester.

b) onthe tenth day after conception.

c) afterthe twelfth week of pregnancy.

d) atthe end of the second trimester.

e) twoweeks before delivery.

Back 361

c) after the twelfth week of pregnancy.

Front 362

A heterozygote witha mutant allele for phenylalanine hydroxylase would have which phenotype?

a) severemental retardation

b) veryfair skin and blue eyes

c) selfdestructive behavior

d) allof the above

e) noneof the above

Back 362

e) noneof the above

Front 363

Which metabolite isrequired for normal production of the skin pigment melanin?

a) phenylalanine

b) ceramide

c) tyrosine

d) bothA and C

e) allof the above

Back 363

d) both A and C

Front 364

The mutationresponsible for cystic fibrosis occurs in a gene that is located on whichchromosome?

a) 1

b) 7

c) 17

d) X

e) Y

Back 364

b) 7

Front 365

Amniocentesis is best performed

a) before the end of the first trimester.

b) on the tenth day after conception.

c) after the twelfth week of pregnancy.

d) at the end of the second trimester.

e) two weeks before delivery.

Back 365

c) after the twelfth week of pregnancy.

Front 366

What lens do you use to see the bacteria in a hanging drop test?

Back 366

the 40X lens.

Front 367

What do you focus on first in a hanging drop test?

Back 367

The edge of the culture drop.

Front 368

Where would you find Hyperthermophiles

Back 368

Hotundersea volcanic vents

Front 369

Explain and state the temperature chosen to keep foods warm

Back 369

Above 65 C.

Very few disease causing bacteria can grow above 65 C

Front 370

Describe why rice salad has frequently been responsible for food poisoning

Back 370

Whenrice is cooled slowly after cooking Bacilluscereus grows rapidly in the rice

Front 371

Give an example of an acidophil and why it is used in foods

Back 371

Lactobacillus.

In yoghurt.

Ferments milk sugarsand produces an acid product.

Acid from fermentation prevents harmful bacteriagrowing

Front 372

how can pH be used in food preservation

Back 372

Acidfrom fermentation prevents harmful bacteria from growing.

Front 373

Explain what can be done to help limit the growth retardation of acid by-products in culture media

Back 373

Buffers counter pH variation.

Phosphate salts buffer in the pH growth range of most bacteria,

they are non toxic and they provide phosphorus and essential nutrient

Front 374

Name two microbes that grow at lower pH range

Back 374

Moulds

yeasts

grow over a larger pH range than bacteria,

an optimum in lower(pH 5 – 6)

Front 375

Osmosis

Back 375

thenet movement of water across a semipermeable membrane from an area of lowersolute concentration to an area of higher solute concentration.

to equalizethe solute concentrations on the two sides

Front 376

Osmotic pressure

Back 376

The osmotic pressure of a solution isthe pressure difference needed tostop the flow of solvent across a semipermeable membrane

Front 377

Define a halophile

Back 377

Anorganism that needs salt to grow

Front 378

What is required for the isolation of Halophiles in growth media

Back 378

The addition of salt to the growth medium

Front 379

Explain aW

Back 379

Wateractivity.

The amount of water free to act

Front 380

examples of food spoilage due to low aW requiring organisms

Back 380

Mould grown on jam after water condensation

Front 381

Identify the classification of bacteria based on atmospheric growth requirements

Back 381

Aerobes- Some microbes require oxygen for energy extraction from organic chemicals

Anaerobes – Somemicrobes can extract energy from organic chemicals only in the absence ofoxygen –

Facultativeanaerobes - Some microbes can extract energy from organic chemicals with andwithout oxygen

Aerotolerantanaerobes – grow equally well no matter the oxygen levels

Microaerophilic – requiring less oxygen thanin the atmosphere but requiring some. Can not grow in air

Front 382

Aerobe

Back 382

Somemicrobes require oxygen for energy extraction from organic chemicals

Front 383

Identify the classification of bacteria based on atmospheric growth requirements

Back 383

Aerobes- Some microbes require oxygen for energy extraction from organic chemicals

Anaerobes – Some microbes can extract energy from organic chemicals only in the absence ofoxygen –

Facultative anaerobes - Some microbes can extract energy from organic chemicals with andwithout oxygen

Aerotolerant anaerobes – grow equally well no matter the oxygen levels

Microaerophilic – requiring less oxygen than in the atmosphere but requiring some. Can not grow in air

Front 384

Facultative anaerobe

Back 384

Some microbes can extract energy from organicchemicals with and without oxygen

Front 385

Aerotolerant anaerobe

Back 385

growequally well no matter the oxygen levels

Front 386

Explain aW

Back 386

Water activity.

The amount of water free to act

Front 387

give an example of one genus of bacteria of facultative anaerobe

Back 387

Escherichiacoli

Front 388

give an example of one genus of bacteria of aerobe

Back 388

Pseudomonasspp.

Front 389

give an example of one genus of bacteria of anaerobe

Back 389

Clostridiumspp.

Bacteroides spp.

Front 390

give an example of one genus of bacteria of Aerotolerant Anarobes

Back 390

Lactobacillusspp.

Front 391

give an example of one genus of bacteria of microaerophilic

Back 391

Campylobacterspp.

Front 392

Identify the generation time of a bacteria

Back 392

Time required for a generation (doubling time) varies due to:

species variation

nutritional factors

Front 393

Growth phases of prokaryotes

Back 393

Exponential growth phase: Cell numbers double at a constant rate:

Stationary phase: If nutrients are limited, cells cannot continue exponential growth indefinitely, also a buildup of waste products will inhibit growth - cells growing = cells dying, no increase or decrease in total cell number

Death phase: No cell growth, cells die and may lyse, due to lack of nutrients/toxic waste products

Front 394

Exponential growth phase (prokaryotes)

Back 394

1. Cell numbers double at a constantrate:

e.g. one E.coli cell after 20 minutes = 2 cells, after 1 hour = 8cells, after 2 hours = 64 cells, after 6 hours = 262,144 cells, after 10 hours= 51,073,741,824 cells

Front 395

Stationary phase (prokaryotes)

Back 395

If nutrients are limited, cells cannot continue exponential growth indefinitely,

also a buildup of waste products will inhibit growth -

cells growing = cells dying,

no increase or decrease in total cell number

Front 396

give an example of one genus of bacteria of Aerotolerant Anarobes

Back 396

Lactobacillus spp.

Front 397

Which one of thefollowing patterns of growth matches an organism below. Grows Chocolate agarbut not Nutrient agar or Horse blood agar.

a) E.coli

b) Neisseriagonorrhoeae

c) Streptococcuspyogenes

d) Bacillussubtilis

e) Staphylococcusepidermidis

Back 397

b) Neisseria gonorrhoeae

Front 398

Which of the following bacteria most likely fits the following description: Large, flat, irregular spreading lactose-fermenting on MacConkey agar

a) Neisseria gonorrhoeae

b) Streptococcus pyogenes

c) Staphylococcus aureus

d) Neisseria meningitidis

e) E. coli

Back 398

e) E. coli

Front 399

Which one of thefollowing agars would be the best to grow streptococci?

a) Nutrientagar

b) MacConkeyagar

c) HorseBlood agar

d) Chocolateagar

e) noneof the above

Back 399

c) Horse Blood agar

Front 400

E. coli cells appearmicroscopically after being Gram stained as

a) gram-positivecocci in chains

b) gram-positivecocci in clusters

c) gram-positiverods

d) gram-negativerods

e) gram-negativecocci

Back 400

d) gram-negative rods

Front 401

Which of the following best describes a colony of bacteria?

a) 1 mm wide, green with yellow edges and green centre

b) 2 mm wide, dome shaped, opaque

c) 3 mm wide, furry and smelly

d) 4 mm wide, large and flat

e) 5 mm wide, spreading and flat

Back 401

b) 2 mm wide, dome shaped, opaque

Front 402

Which one of thefollowing agars would be the minimum required to grow staphylococci?

a) Nutrientagar

b) MacConkeyagar

c) HorseBlood agar

d) Chocolateagar

e) noneof the above

Back 402

a) Nutrient agar

Front 403

Some bacteria canmove across an agar surface creating a film of growth. This is called

a) motility

b) swarming

c) clouding

d) swimming

e) sliding

Back 403

b) swarming

Front 404

Which agar would bemost useful when examining a mixture of gram-negative bacteria?

a) Nutrientagar

b) MacConkeyagar

c) HorseBlood agar

d) Chocolateagar

e) noneof the above

Back 404

b) MacConkey agar

Front 405

Which one of the following agars would be the minimum required to grow staphylococci?

a) Nutrient agar

b) MacConkey agar

c) Horse Blood agar

d) Chocolate agar

e) none of the above

Back 405

a) Nutrient agar

Front 406

E. coli cells appear microscopically after being Gram stained as

a) gram-positive cocci in chains

b) grams positive cocci in clusters

c) gram-positive rods

d) gram-negative rods

e) gram-negative cocci

Back 406

d) gram-negative rods

Front 407

Lactosefermentation can be seen as

a) Pinkcolonies on MacConkey agar

b) Colourlesscolonies on MacConkey agar

c) Haemolyticcolonies on Horse blood agar

d) Bubblesin the agar medium

e) Swarmingon Horse blood agar

Back 407

a) Pink colonies on MacConkey agar

Front 408

Horse blood agar (HBA) grows a greater variety of organisms than Nutrient agar

a) False, nutrient agar has extra ingredients, but HBA only grows blood-borne bacteria

b) False, nutrient agar is multi-purpose, but HBA has only few uses

c) False, nutrient agar grows soil and animal bacteria, but HBA only grows animal bacteria

d) True, HBA grows every bacteria that has been discovered

e) True, some bacteria are unable to grow unless blood is used to enrich the agar

Back 408

e) True, some bacteria are unable to grow unless blood is used to enrich the agar

Front 409

Which of thefollowing ingredients gives MacConkey agar differential properties

a) peptone

b) bilesalts

c) sodiumchloride

d) lactose

e) agar

Back 409

d) lactose

Front 410

Which of thefollowing is enriched and differential?

a) Nutrientagar

b) MacConkeyagar

c) HorseBlood agar

d) Chocolateagar

e) noneof the above

Back 410

c) Horse Blood agar

Front 411

Streptococci arebest described microscopically as

a) gram-negativerods

b) gram-positiverods

c) gram-negativecocci

d) gram-positivecocci in clusters

e) gram-positivecocci in chains

Back 411

e) gram-positive cocci in chains

Front 412

In order to find Bacillus anthracis in a soil sample, it would be usefulto

a) usea differential agar such as MacConkey agar

b) grow soil in broth before subculturing to agar

c) use an enriched agar such as Chocolate agar

d) investigate colonies that have a typical morphology expected for the organism

e) look for swarming colonies on HBA

Back 412

d) investigate colonies that have a typical morphology expected for the organism

Front 413

Chocolate agarcontains additional carbohydrate compared to Horse blood agar

a) True,it is a sweeter form of agar that increases the growth rate of bacteria

b) True,the extra carbohydrate makes the agar darker than HBA

c) True,there are three different sugars present instead of the single sugar in HBA

d) False,chocolate agar is a vegetarian version of a blood product

e) False,chocolate agar is a cooked version of HBA

Back 413

e) False, chocolate agar is a cooked version of HBA

Front 414

Which of the following best describes how HBA can be both enriched and differential as agar

a) E. coli will be larger and more grey in colour than a Staphylococcus colony

b) Streptococcus pyogenes will be haemolytic, but Neisseria meningitidis is not

c) Some bacillus colonies will have a ground glass surface, while others will be smooth

d) Klebsiella colonies will be large and dome shaped while E. coli will be large and flat

e) Staphylococcus epidermidis colonies may be whiter than Staphylococcus aureus

Back 414

b) Streptococcus pyogenes will be haemolytic, but Neisseria meningitidis is not

Front 415

Chocolate agar contains additional carbohydrate compared to Horse blood agar

a) True, it is a sweeter form of agar that increases the growth rate of bacteria

b) True, the extra carbohydrate makes the agar darker than HBA

c) True, there are three different sugars present instead of the single sugar in HBA

d) False, chocolate agar is a vegetarian version of a blood product

e) False, chocolate agar is a cooked version of HBA

Back 415

e) False, chocolate agar is a cooked version of HBA

Front 416

Which of thefollowing ingredients gives MacConkey agar selective properties

a) peptone

b) bilesalts

c) lactose

d) NeutralRed

e) agar

Back 416

b) bile salts

Front 417

The definition of symbiosis is:

a) the process in which one cell divides to form two

b) a process in which two cells can transfer DNA via a pilus

c) a cellular process in which amino acids are converted to proteins

d) a relationship between two organisms

e) a process in which a spore is converted to a vegetative cell

Back 417

d) a relationship between two organisms

Front 418

Bacteria that benefit from living in the body without causing any harm are called:

a) Commensals

b) Mesophiles

c) Pathogens

d) Organotrophs

e) Extremophiles

Back 418

a) Commensals

Front 419

Where in the human body would you find the largest amount of microbes?

a) Mouth

b) Nose

c) Small Intestine

d) Large Intestine

e) Genitourinary tract

Back 419

d) Large Intestine

Front 420

A throat swab is taken from a healthy individual and a mixture of bacteria grows on the plate. This most likely indicates:

a) Tonsillitis

b) Influenza

c) Normal throat flora

d) More tests are needed to make a diagnosis

e) Broad spectrum antibiotics should be prescribed

Back 420

c) Normal throat flora

Front 421

In prac class a student places their hand on an agar plate. Following incubation the plate is covered in E. coli. This represents:

a) Normal skin flora

b) A skin infection

c) Normal flora of the oral cavity

d) Faecal contamination of hands

e) Normal nasopharyngeal flora

Back 421

d) Faecal contamination of hands

Front 422

Which of the following is not an example of commensal relationship?

a) Staphylococcus epidermidis growing on the skin

b) Staphylococcous aureus growing in the nose

c) Neisseria gonorrhoeae growing on urethral epithelial cells

d) E. coli growing in the large intestine

e) Nonpathogenic streptococci growing in the throat

Back 422

c) Neisseria gonorrhoeae growing on urethral epithelial cells

Front 423

Which of the following is true about a mutualistic relationship:

a) One organism benefits

b) Both organisms benefit

c) One organism benefits and the other is harmed

d) Neither organism benefits or is harmed

e) Both organisms are harmed

Back 423

b) Both organisms benefit

Front 424

Which of the following describes a parasitic relationship?

a) One organism benefits whilst the other remains unaffected

b) Both organisms benefit

c) One organism benefits and the other is harmed

d) Neither organism benefits or is harmed

e) Both organisms are harmed

Back 424

c) One organism benefits and the other is harmed

Front 425

Rumen Bacteria found in the stomachs of cows are an example of a:

a) Commensal relationship

b) Mutualistic relationship

c) Neutralistic relationship

d) Parasitic relationship

e) Mixed relationship

Back 425

b) Mutualistic relationship

Front 426

The growth of Giardia in the large intestine is an example of:

a) Commensal relationship

b) Mutualistic relationship

c) Neutralistic relationship

d) Parasitic relationship

e) Amensalism

Back 426

d) Parasitic relationship

Front 427

Which of the following describes how a disease may be transmitted indirectly through a vector?

a) Kissing

b) Sharing a drink bottle

c) Eating a chicken dish that has not been cooked properly

d) Sitting near someone who is coughing and sneezing

e) Being bitten by a mosquito

Back 427

e) Being bitten by a mosquito

Front 428

Acquiring a disease as a result of touching a contaminated door handle is an example of:

a) Droplet transmission

b) Airborne transmission

c) Direct contact transmission

d) Indirect contact transmission

e)Vector borne transmission

Back 428

d) Indirect contact transmission

Front 429

Flies crawling on prepared food is an example of how disease may be spread by:

a) Direct contact transmission

b) Indirect contact transmission

c) Vector borne transmission

d) Airborne transmission

e) Vertical transmission

Back 429

c) Vector borne transmission

Front 430

Which of the following diseases is mostly transmitted directly from person to person?

a) Gonorrhoea

b) Salmonella gastroenteritis

c) Malaria

d) S. aureus food poisoning

e) E. coli urinary tract infection

Back 430

a) Gonorrhoea

Front 431

Where in the body are you not likely to find commensals?

a) Skin

b) In the nose

c) In the mouth

d) Lungs

e) Large Intestine

Back 431

d) Lungs

Front 432

Where in the body would the presence of Staphylococcus indicate disease?

a) Skin

b) Nose

c) Blood stream

d) Vagina

e) Large Intestine

Back 432

c) Blood stream

Front 433

Bacteria commonly found in the body that cause disease in a person with a weakened immune system are called:

a) Phagocytes

b) Extremeophiles

c) Commensals

d) Neutrophils

e) Opportunistic pathogens

Back 433

e) Opportunistic pathogens

Front 434

The normal flora of the large intestine is beneficial in:

a) Minimising available sites for pathogens colonize

b) The secretion of antimicrobial substances

c) The production of certain vitamins

d) Assisting digestion

e) All of the above are true

Back 434

e) All of the above are true

Front 435

Which of the following best describes the term pathogen?

a) A common bacterium in the body that doesn’t cause any harm

b) A microorganism that infects a host

c) A commensal that causes disease in a person following a course of antibiotics

d) A commensal that grows in a person when their immune system is compromised

e) A microorganism that grows in the host and causes harm

Back 435

e) A microorganism that grows in the host and causes harm

Front 436

What is the benefit of Lactobacillus in the Vagina?

a) Increases pH preventing growth of pathogens

b) Decreases pH preventing growth of pathogens

c) Inhibits the growth of commensals

d) Resistant to antibiotics

e) None of the above

Back 436

b) Decreases pH preventing growth of pathogens

Front 437

commensalism,

Back 437

Symbiotic relationship

the host (e.g. human, plant, fungi) receives no benefit or harm,

the microbe benefits from the interaction

Front 438

mutualism,

Back 438

Symbioticrelationship

both organismsbenefit

Front 439

neutralism

Back 439

Symbioticrelationship

neither organism benefitsor is harmed by the interaction

Front 440

parasitism,

Back 440

Symbiotic relationship

negative effect on host,

positive effect on microbe

Front 441

amenasalism

Back 441

Symbiotic relationship

no effect on host,

negative effect on microbe

Front 442

symbiosis

Back 442

therelationship between the normal microbiota and the host

Front 443

example of a commensalist organism

Back 443

Staphylococcus epidermidis

grows on the surface on skin,

feeds on sebum secretions,

no negative effect for host

Front 444

example of a mutualist organism

Back 444

rumen of cattle

-allow cellulose digestion,

-the microbes receive a warm, protected environment and nutrients from food

legumes and Rhizobacteria

-allow for nitrogen fixation in the root nodules,

-the nitrogen is used by the plant,

-the bacteria obtains carbohydrates

Lichen

- made up of a fungus and an alga,

-the fungus provides a protective structure

-the alga is photosythetic, providing food

Front 445

example of a parasitic organism

Back 445

Pseudomonas aeruginosa

– loves moisture,

-also attaches well to plastic

Front 446

Genotype

Back 446

genetic constitution of an individual

Front 447

Phenotype

Back 447

1. observable trait or set of traits of an individual

Phenotype produced by interaction between genotype and environment

Front 448

Genetic traits

Back 448

1. characteristics of an individual

Some traits heritable, others not

Front 449

Mendel’s studies on garden peas:

Back 449

1. Selected model genetic organism (peas)

Studied one trait at a time

Simple interpretation of results

Direct experiments to prove hypothesis

Front 450

Why were peas a good genetic organism?

Back 450

1. easy to grow, short life cycle,

produced large number of seeds -

each plant has stamens and pistils -

normally self fertilise

enabled Mendel to have strict control over mating

-each seed had an embryo

Front 451

Seven different characters that Mendel studied

Back 451

1. -seed shape smooth/wrinkled-seed

coat colour/flower colour grey seedcoat, purple flower/white both

-seed colour yellow/green

-pod colour yellow/green

-pod shape inflated/pinched

-stem height tall/short

-flower position axial/terminal

Front 452

discrete’characteristics

Back 452

1. Either/or characteristics•

- no intermediate phenotype•

e.g., smooth or wrinkled seeds

Front 453

continuous’characteristics

Back 453

1. Characteristics that change on a gradient

Front 454

true-breedingstrain

Back 454

1. when the plants are allowed to self-pollinatefor many generations,

all the offspring were genetically identical

Front 455

purebreeding strain’?

Back 455

1. when the plants are allowed to self-pollinatefor many generations,

all the offspring were genetically identical

Front 456

bacteria that is often on dry skin,

Back 456

1. Staphylococcusepidermidis

Front 457

bacteria that is often in the nasal cavity,

Back 457

Staphylococcus aureus,

Staphylococcus epidermis

Front 458

bacteria that is often in the mouth,

Back 458

Staphylococcus,

Streptococcus,

Lactobacillus,

Neisseria,

Candida

Front 459

bacteria that is often in the large intestine,

Back 459

E.coli,

Lactobacillus,

Bacteroides,

Enterococcus

Front 460

bacteria that is often in the vagina

Back 460

Staphylococcus,

Streptococcus,

Clostridium,

Candida,

Bacteroides

Front 461

State some benefits to humans of normal flora in the large intestine

Back 461

productionof vitamins B12 and K

aid in food digestion

Front 462

bacteria that is often on dry skin,

Back 462

1. Staphylococcus epidermidis

Front 463

Opportunistic pathogen

Back 463

only cause disease in the absence of normalhost resistance

or when an opportunity exists

Front 464

Infection

Back 464

1. wherea microorganism is growing in a host, with or without host damage

Front 465

disease

Back 465

1. damagethat impairs host function

Front 466

Mendel’s monohybrid cross:

Back 466

-used true breeding varieties

-breeding for a single characteristic

Front 467

P generation

Back 467

1. Parents: Female and Male

Front 468

F1 generation

Back 468

-the first filial generation

-offspring of ‘P’ Generation

Front 469

pathogen

Back 469

The parasite grows as the expense of the host,

causing damage while obtaining nutrients and a favourable environment

The pathogenicity of a parasite is measured by its virulence

Front 470

Whatwas the ratio of F2 individuals he obtained in monohybrid cross?

Back 470

3:1ratio

Front 471

Dominantcharacter

Back 471

1. dominant allele fully expressed in appearance

Front 472

Law of segregation:.

Back 472

Recessive traits, which are masked in the F1from a cross between two true breeding strains, reappear in a specificproportion in the F2

two members of a gene pair (alleles)segregate (separate) from each other during gamete formation in meiosis

Front 473

letteringconvention used to denote alleles.

Back 473

Dominant allele represented by ‘capital’ letterand recessive allele by ‘small’ letter

e.g., Smooth seeds (S), Wrinkled seeds(s)

(Ss)

Front 474

Law of segregation:

Back 474

Recessive traits not seen in F1 reappear in a specific proportion in the F2

two alleles separate from each other during gamete formation in meiosis

Front 475

The firstgeneration in a series of monohybrid crosses is referred to as the ___generation.

a) F1

b) F2

c) A

d) P

Back 475

a) F1

Front 476

F2 generation

Back 476

- the second filial generation

-offspring produced by interbreeding ‘F1 l’individuals

Front 477

In a monohybrid cross between two true-breeding parents that both exhibit the dominant phenotype, ___ percent of the offspring will exhibit the recessive phenotype.

a) 50

b) 0

c) 100

d) 25

Back 477

b) 0

Front 478

In a monohybridcross between two true-breeding parents, one showing the dominant phenotype andthe other the recessive phenotype, the phenotypic ratio in the F2 generation isexpected to be ____________________.

a) 1:2:1.

b) 2:1.

c) 3:1.

d) 1:1.

Back 478

c) 3:1.

Front 479

In a cross betweentwo homozygous dominant parents, the number of phenotypic classes observed inthe offspring is ____________________.

a) 2.

b) 1.

c) 4.

d) 3.

Back 479

b) 1.

Front 480

In a cross betweena homozygous dominant parent and a homozygous recessive parent, the number ofphenotypic classes observed in the offspring is ____________________.

a) 4.

b) 3.

c) 2.

d) 1.

Back 480

d) 1.

Front 481

In a cross between 2 heterozygous parents, the expected number of phenotypic classes in the offspring is ____________________.

a) 2.

b) 4.

c) 1.

d) 3.

Back 481

a) 2.

Front 482

In a testcross, anindividual of unknown genotype is crossed with a ___ individual to determinethe unknown genotype.

a) hemizygous

b) homozygousdominant

c) heterozygous

d) homozygousrecessive

Back 482

d) homozygous recessive

Front 483

An individual with the dominant phenotype, but an unknown genotype, is testcrossed, and all of the offspring exhibit the dominant phenotype. The genotype of the unknown individual is ____________________.

a) homozygous recessive.

b) heterozygous dominant.

c) homozygous dominant.

d) heterozygous recessive.

Back 483

c) homozygous dominant.

Front 484

In a particular type of tomato plant, red fruit color is dominant over yellow. In a cross between a heterozygous plant and a homozygous recessive plant, what percentage of the offspring would have yellow fruit?

a) 100

b) 0

c) 50

d) 25

Back 484

c) 50

Front 485

In a particulartype of tomato plant, red fruit is dominant over yellow fruit, and dwarf heightis a recessive trait. If two plants that were heterozygous for both traits werecrossed, what proportion of the offspring would show the recessive phenotype?

a) 1/8

b) 1/2

c) 1/16

d) 1/4

Back 485

c) 1/16

Front 486

In a particulartype of tomato plant, red fruit is dominant over yellow fruit, and dwarf heightis a recessive trait. If two heterozygous plant were crossed, what proportionof the offspring would show the dominant phenotype?

a) 9/16

b) 2/3

c) 3/8

d) 1/4

Back 486

a) 9/16

Front 487

In a particulartype of melon, orange fruit is dominant over green fruit, and round shape if dominantto oval. If a plant that was heterozygous for both traits was crossed with aplant that was homozygous recessive for both traits, what proportion of theoffspring would be heterozygous?

a) 3/4

b) 1/4

c) 1/2

d) 9/16

Back 487

b) 1/4

Front 488

An albino womanmarries a phenotypically normal man with no family history of albinism. What percentageof their children are likely to be albino?

a) 25

b) 100

c) 50

d) 0

Back 488

d) 0

Front 489

What percentage of the children of a woman with achondroplasia will carry the disease causing allele?

a) 25

b) 50

c) 0

d) 100

Back 489

b) 50

Front 490

Two phenotypicallynormal people have 4 children. 3 are phenotypically normal like their parents,but one is an albino. What are the probable genotypes of the parents?

a) Bothparents are homozygous recessive.

b) Oneparent is homozygous dominant and one is homozygous recessive.

c) Bothparents are heterozygous.

d) Bothparents are homozygous dominant.

Back 490

c) Both parents are heterozygous.

Front 491

The statisticaltest used to determine if an observed set of data differs significantly fromthe expected results is the ________ test.

a) studentt-

b) bestfit

c) productrule

d) chi-square

e) ANOVA

Back 491

d) chi-square

Front 492

The inheritance of traits in humans is best studied by

a) performing carefully controlled mating experiments.

b) construction and evaluating family pedigrees.

c) performing and evaluating chi square tests.

d) all of the above

e) none of the above

Back 492

b) construction and evaluating family pedigrees.

Front 493

SS

Back 493

1. homozygous dominant individual

Front 494

Ss

Back 494

1. heterozygous individuals

Front 495

ss

Back 495

1. homozygous recessive individual

Front 496

The inheritance of traits in humans is best studied by

a) performing carefully controlled mating experiments.

b) construction and evaluating family pedigrees.

c) performing and evaluating chi square tests.

d) all of the above

e) none of the above

Back 496

b) construction and evaluating family pedigrees.

Front 497

1. homozygous dominant individual

Notation

Back 497

SS

Front 498

1. heterozygous individuals

Notation

Back 498

Ss

Front 499

The statistical test used to determine if an observed set of data differs significantly fromthe expected results is the ________ test.

a) student t-

b) best fit

c) product rule

d) chi-square

e) ANOVA

Back 499

d) chi-square

Front 500

Back 500

Punnett square.

Front 501

Test Cross

Back 501

1. if have an unknown genotype

-homozygous or heterozygous?

-cross it with a true breeding recessive

-can determine the genotype of the individual

Front 502

Mendel’s dihybrid cross:

Back 502

1. Looking at how two allele pairs will be inherited.

Smooth Yellow (SSYY) crossed with wrinkled green (ssyy)

gave Mendel all Smooth Yellow (SsYy) in F1 generation

9 Smooth Yellow: 3 Smooth green: 3 wrinkled Yellow: 1 wrinkled green in the F2 generation.

Front 503

SsYy x SsYy genotype combinations

Back 503

produces16 individuals

9 different genotype combinations

4 differentphenotypes

Front 504

Independent Assortment

Back 504

1. Mendel examined crosses for parents which differed in 2 characters

• - SY, sY, Sy and sy combinations of gametes in alleles

• sperm and ovum produce 16 classes of allele combinations

• 4 phenotypic classes

• 9:3:3:1 ratio

Front 505

Methods of transmission of disease

Back 505

1. Contacttransmission

-Direct contacttransmission

-Indirect contacttransmission

-Droplet transmission

Vehicletransmission

-water,

-food,

-airborne

Vectors

-Arthropods

-Mechanical transmission

-Biological transmission

Front 506

‘opportunistic pathogen’ by using the example of Pseudomonas

Back 506

1. Tinea can lead to Pseudomonas having a secondary opportunistic infection

once the skin has cracked,

making it wet and smelly.

Front 507

Contact transmission

Back 507

-Directcontact transmission

- Indirect contacttransmission

- Droplettransmission

Front 508

Vehicle transmission

Back 508

water,

food,

airborne

Front 509

Explain why the asymptomatic stage of infection is important in transmission

Back 509

1. Spreadingthe organism before you know you know you are infected

Front 510

Explain why Koch’s postulates have been refined

Back 510

Whenthe causative organism cannot be cultured in the laboratory

– e.g. Mycobacteriumleprae, the causative agent of leprosy

-When thecausative organism will only grow as a co-culture

– e.g. viruses will onlygrow inside a host cell

-Whendiseases/effects require more than one organism to be present

Front 511

SsYy x SsYy genotype combinations

Back 511

produces 16 individuals

9 different genotype combinations

4 different phenotypes

Front 512

If the results of a chi-square test on a particular set of data show a P value greater than 0.05, then the hypothesis

a) must be rejected.

b) must not be accepted.

c) cannot be rejected.

d) must not be valid.

Back 512

c) cannot be rejected.

Front 513

In humans, recessive traits are expressed in

a) females only.

b) every generation.

c) a person with one recessive allele.

d) a person with two recessive alleles.

e) both A and C

Back 513

d) a person with two recessive alleles.

Front 514

The offspring of two phenotyically normal people who are heterozygotes for albinism would be expected to exhibit which phenotypic ratio of normal to affected individuals?

a) 3:1

b) 1:1

c) 1:2:1

d) 1:3

e) 4:0

Back 514

a) 3:1

Front 515

Contact transmission types

Back 515

-Direct contact transmission

- Indirect contact transmission

- Droplet transmission

Front 516

Which of thefollowing is true concerning the inheritance of a dominant trait?

a) Everyaffected person must have one affected parent.

b) Thetrait is observed in every generation.

c) Anaffected heterozygote will transmit the allele to half of his or her offspring.

d) allof the above

e) noneof the above

Back 516

d) all of the above

Front 517

For a single trait, the offspring of true-breeding parents may

a) resemble only one parent.

b) be exactly alike.

c) be a blend of both parental phenotypes.

d) both A and B

e) all of the above

Back 517

d) both A and B

Front 518

The probability that two parents will have 3 girls and 1 boy in their family may be determined using the

a) product rule.

b) sum rule.

c) student t-test.

d) chi-square test.

e) all of the above

Back 518

a) product rule.

Front 519

The probability that two parents will have 3 girls and 1 boy in their family in that order is

a) 1/2.

b) 1/4.

c) 1/8.

d) 1/16.

e) 1/32.

Back 519

d) 1/16.

Front 520

What is theprobability that the first child of two parents is a girl?

a) 1/4

b) 1/2

c) 1/8

d) 1/16

e) 1/256

Back 520

b) 1/2

Front 521

For any given gene,the principle of segregation predicts that gametes produced as a result ofmeiosis will contain ____________________.

a) halfof both alleles of the gene pair.

b) halfof one allele of a gene pair.

c ) a single allele of a gene pair.

d) bothalleles of a gene pair.

Back 521

c) a single allele of a gene pair.

Front 522

Individuals that are heterozygous for a particular trait have

a) two different alleles of the gene.

b) multiple copies of the gene.

c) two identical copies of the gene.

d) two different genes responsible for the trait.

e) two identical alleles of the gene.

Back 522

a) two different alleles of the gene.

Front 523

product rule

Back 523

The probability of two mutually exclusive eventsoccurring together is the multiplication of the individual probabilities

-Multiplying the frequency of alleles to findproportion of progeny phenotypes

Front 524

allele

Back 524

1. Same gene with a slightly different sequence

Front 525

A chemical used in food preservation

Back 525

1. Sodium nitrite

Front 526

potential problem of sodium nitrate use

Back 526

-acarcinogen precursor

-Lengthy and costly testing programs required to ensure food safety

Front 527

Define sterilisation

Back 527

killing/removal/inactivation of all viable organisms

-including endospores

Front 528

List some parameters used to control growth of microbes

Back 528

- temperature,

- pH,

- water levels (aw),

- oxygen levels

Front 529

Illustrate the problem of microbes growth in the cold using the Listeria example

Back 529

Listeria can cause death in utero

meningitis in theimmunocompromised.

grows at 4 C.

Front 530

some methods of control of microbes using heat

Back 530

-Pasteurisation

-Tyndallisation

-Boiling

-Hot air oven

-Incineration

-Autoclaving

Front 531

Tyndallisation

Back 531

1. 80°Con 3 successive days

Front 532

Boiling

Back 532

1. 100°C

Front 533

Hot air oven

Back 533

1. 160-180°C

Front 534

Autoclaving

Back 534

1. steamat >100°C

Front 535

pasteurisation

Back 535

-routinely used for juice and milk

-retards growth of spoilage organisms,

-increases shelf life

-Foods can be boiled at 100°C

-doesn’t kill endospores

-may change taste and physical properties of heat-sensitive foods

-Not a process of sterilisation,

-reduces microbial numbers

-kills pathogenic bacteria including Listeria and Campylobacter

Front 536

disinfection

Back 536

1. Killing/removal of all vegetative forms, notincluding endospores

Front 537

ways in which endospores are more resistant to killing

Back 537

- Resistant to heat ,

can withstand temperaturesof 150°C

- resistant to UV radiation

- resistant to chemical disinfectants

Front 538

autoclaves

Back 538

-Generally heat till 1210C and

-then hold for 15 minutes

-Flash sterilisers (tend to be smaller bench-style)

-1340C for 3 minutes

-Important to allow flush out of air

- air trapped in load poor transfer of heat

-Condensation on items allows transfer of heat rather than conduction

-Drying cycle important as bugs can pass through wet packs

Front 539

Estimate the time needed to have 99.9% kill from a supplied graph

Back 539

9 minutes

-log 10 equals 1

-number of organisms reduced by a power of 10 each minute.

- At 3 minutes, 10 organisms were left

-If we were 90% sure then there is a 10% chance an organism is still alive (1/10)

-If we were 99% sure then there is a 1% chance an organism is still alive (1/100)

-So a 99.9% kill requires 3 log reductions,

-or 3 lots of the time it takes for a 10 fold reduction below the time it takes to reach 100 organisms

Front 540

Describe factors that may influence the ability to sterilize in an autoclave

Back 540

-starting number of organisms,

-pre-cleaning important

-Size/volume of item

-Dry items take longer to sterilise than moist ones,

-high amounts of sugars, proteins or fats in the medium decreases heat penetration

-Some items cannot be sterilised by steam, e.g. talc, ointments

Front 541

ionising radiation

Back 541

-High-energy radiation particles which produceelectrons and free radicals from molecules they collide with

- These radicals disrupt DNA and proteins inthe cells, leading to death

Front 542

Describe the different form of filtration

Back 542

-Membrane filters

-for liquids 0.2 µm (1/20,000th of 1 mm) pore commonly used

-HEPA (High efficiency particulate air) filters

-to filter air

-99.97% efficient

-remove particles as small as 0.3 microns

Front 543

Identify different biological cabinets in the laboratory and their uses

Back 543

-UV radiation:

-between 220-300 nm wavelength light,

-causes modifications and double stranded breaks in cell DNA, leading to death

-“Biohazard” cabinets use UV light to sterilise surfaces before/after use

Front 544

A hospital purchases a new autoclave. They wantto know if they have an outbreak of a bad diarrhoeal bacteria, how long willthey need to autoclave the sheets before sending to the laundry, to be 99.9%sure they have killed the bacteria.

Back 544

9 minutes It look

4 minutes to go from 106 to 102 organisms (1000000 to 100)

after 2 more minutes there will be 100 which is 1 organism.

After 1 more minute there is a 1/10 chance an organism is still alive.

After another minute there is a 1/100 chance or 1% chance a bug is still alive, i.e., we can be 99% sure the bugs are dead.

In one more minute we can be 99.9% sure.

Front 545

A HEPA filter can filter particles as small as 0.3 microns. It is likely to be effective in filtering

a) Liquids

b)Liquids and dust particles

c) Dust particles and largemicroorganisms

d)Bacteria and viruses

e) Bacteria but probably notviruses

Back 545

1. (e) Bacteria but probably not viruses

Front 546

You have some meat that has been in the refrigerator and is starting to smell. You decide that a good way to reduce the microbial contamination would be to freeze it. This works

a) By killing bacteria cells

b) By killing both bacteria and viruses

c) Only onparasitic worms

d) By killingbacteria and spores

e) By killing allmicroorganisms

Back 546

c) Only on parasitic worms

Front 547

You decide that since UV radiation is a sterilising agent, putting bedding and mats out in the sunlight will have a sterilising effect. This statement is

a) Correct as UV radiation does sterilise

b) Correct as surface sterilisation should be sufficient

c) Incorrect as UV radiation is only a surface steriliser

d) Partially correct as it will reduce the bacterial loadon the items

e) Incorrect as UV radiation does not kill viruses

Back 547

d) Partially correct as it will reduce the bacterial load on the items

-as a surface steriliser

Front 548

Sterilization is a process

a) used to destroy all viable cells and spores

b) that destroys viable cells but not endospores

c) used to reduce microbial numbers to a safe level

d) used to kill bacteria but not viruses

e) that is only useful in killing gram negative bacteria

Back 548

a) used to destroy all viable cells and spores

Front 549

Endospores are very resistant to:

a) Heat

b) Disinfectants

c) Detergents

d) UV radiation

e) All of the above

Back 549

e) All of the above

Front 550

What is the potential problem of using sodium nitrite as a food preservative?

a) It reduces the growth of food spoilage microbes allowing pathogens to grow favourably

b)It inhibits the growth of pathogens allowing the rapid growth of spoilage microbes

c) It is a carcinogen precursor and large amounts may be toxic to consumers

d) It neutralises the pH of food allowing alkalophilic bacteria to grow favourably

e) It gives food an displeasing taste

Back 550

c) It is a carcinogen precursor and large amounts may be toxic to consumers

Front 551

A fermented food such as pickled cucumbers is very resistant to spoilage by bacteria owing to:

a) A low pH

a) A high pH

b) A low water availability

c) A high water availability

d) Both (a) and (c) are the most correct

Back 551

a) A low pH

Front 552

What makes raw meat highly susceptible to the growth of spoilage bacteria:

a) Almost neutral pH

b) High water availability

c) High availability of oxygen at the meat surface

d) Copious nutrients

e) All of the above are correct

Back 552

e) All of the above are correct

Front 553

How does the addition of sugar or salt to a product assist in controlling microbial growth:

a) Decreases pH

b) Decreases available water

c) Increases redox potential

d) Increases water availability

e) Increases pH

Back 553

b) Decreases available water

Front 554

Fruits are not a favourable growth environment for spoilage bacteria.

This is because fruits have:

a) A high water activity

b) A low water activity

c) Have a neutral pH

d) Have a alkaline pH

e) Have an acidic pH

Back 554

e) Have an acidic pH

Front 555

Which of the following is true about the growth of Listeria

a) Viable cells are destroyed at 4 C

b) Growth is inhibited at 4C

c) Growth occurs slowly at 4 C

d) Viable cells are very resistant to heat

e) (b) and (d) are both true

Back 555

c) Growth occurs slowly at 4 C

Front 556

Which of the following processes is used for sterilization:

a) Pasteurization

b) Boiling

c) Autoclaving

d) Freezing

e) All of the above are true

Back 556

c) Autoclaving

Front 557

How does boiling control microbial growth:

a) Reduces the number of viable cells to a safe level

b) It inactivates viable cells but spores are resistant

c) It inactivates spores but viable cells may survive

d) It slows microbial growth by causing membranes to lose their fluidity

e) It kills viable cells and spores

Back 557

b) It inactivates viable cells but spores are resistant

Front 558

Which of the following is not true regarding pasteurisation:

a) It increases the shelf life of a product

b) It kills pathogens

c) It decreases the amount of food spoilage microbes

d) It is routinely used on heat sensitive foods such as milk and juice

e) It makes a product sterile until it is opened

Back 558

e) It makes a product sterile until it is opened

Front 559

What would be the best way to sterilise antibiotics before adding to culture media?

a) Pasteurization

b) Boiling

c) Autoclaving

d) Filtration

e) Tyndallisation

Back 559

d) Filtration

Front 560

Autoclaving achieves sterilization through the use of:

a) Pressurised steam

b) Dry heat

c) Toxic gasses such as ethylene oxide

d) Toxic chemicals such as sodium hydroxide

e) Ionising radiation

Back 560

a) Pressurised steam

Front 561

Which of the following items can be sterilised by autoclaving:

a) Antibiotics

b) Amino acids

c) Volatile solvents such as ethanol

d) Fluids

e) Talc

Back 561

d) Fluids

Front 562

Which of the following factors might effect how long an item needs to be autoclaved to achieve sterility:

a) The initial number of microbes

b) The viscosity of a solution

c) The size of an item

d) The volume of an item

e) All of the above are true

Back 562

e) All of the above are true

Front 563

In which of the following solutions would you expect heat penetration to be the slowest:

a) A jar containing water

b) A jar containing saline

c) A jar containing 2% oatmeal

d) A jar containing 4% oatmeal

e) Heat would penetrate all of the above solutions equally

Back 563

d) A jar containing 4% oatmeal

Front 564

For which of the following tasks would you use a biological safety cabinet:

a) When working with volatile chemicals

b) When preparing an E. coli purity plate

c) When gram-staining a heat fixed smear

d) When working with a hazardous pathogen such as Mycobacterium tuberculosis

e) For storing waste

Back 564

d) When working with a hazardous pathogen such as Mycobacterium tuberculosis

Front 565

Which of the following is true about the growth of Listeria

a) Viable cells are destroyed at 4 C

b) Growth is inhibited at 4C

c) Growth occurs slowly at 4 C

d) Viable cells are very resistant to heat

e) (b) and (d) are both true

Back 565

c) Growth occurs slowly at 4 C

Front 566

A vial containing Bacillus stereothermophilus spores is placed in a standard autoclave run (121 C, 20 minutes).

It is then incubated in broth at 55 C overnight.

What information will this provide about sterilization effectiveness (pick the best response)?

a) Germination of spores indicate the autoclave is working

b) Germination of spores indicate the autoclave is not working

c) No growth indicates the autoclave is working

d) No growth indicates the autoclave is not working

e) It will not provided any useful information as spores cannot be grown until germinated

Back 566

c) No growth indicates the autoclave is working

Front 567

UV light is effective in the sterilization of:

a) The flat surfaces of a biological hazard cabinet

b) The surface of an opened nutrient agar plate

c) Large amounts of waste

d) Test tubes with their lids on

e) Both (a) and (b) are true

Back 567

e) Both (a) and (b) are true

Front 568

chemical sterilant,

Back 568

- Chemical sterilants used in hospitals etcon heat-sensitive equipment, such as thermometers, tubing, will kill endospores

- enclosed chambers,

- gas added such asformaldehyde/hydrogen peroxide

Front 569

disinfectant

Back 569

- may not kill endospores,

-used on surfaces

Includes:

-ethanol,

-cationic detergents,

-bleach(sodium hypochlorite)

Front 570

antiseptic

Back 570

kill/inhibit growth of microorganisms but are non-toxic enough to be used on living tissue

Front 571

sanitiser

Back 571

reduce microbial numbers to “safe” levels

Front 572

List factors that adversely affect the function of disinfectants

Back 572

-Action of disinfectants affected by material surrounding the microorganisms

-Presence of proteins, fats etc in the -surrounding area will protect microorganisms,

-many disinfectants are neutralised by organic materials

-Some microorganisms form biofilms

-Penetration of chemicals reduced

-Major problem in hospitals, biofilm formation on catheters etc

Front 573

Give examples of what disinfectants have trouble killing or inactivating

Back 573

- spores,

-TB bacteria

-some viruses

Front 574

hypochlorites

Back 574

-Excellentvirucidal

- Must be diluted

- Corrodes metal

-Inactivated by organic matter

- Needs to be made up fresh

Front 575

Calculate the dilution required to make 5% hypochlorite 5000 parts per 1,000,000 for 10ml

Back 575

1. C1 V1 = C2 V2

5 per 100 x V1 = 5000/1000000 x10 ml

Solve for V1

V1 = 5000/1000000 x 10 x 100/5

V1 = 1 ml

Front 576

how alcohol is used as a disinfectant

Back 576

- Suitablefor skin

- doesn’t kill all viruses

- 70% alcohol is better than 100%

Front 577

Name the characteristics of a good hand wash solution

Back 577

Goodwetting properties

Rinses well

Residual activity

Chlorhexidine good residual

Front 578

Describe the steps in good hand washing technique

Back 578

Wet hands first

Add hand-wash solution

Rub hands, include wrists finger webbing

Scratch palms of hands with each finger to get soap under fingernails

Rinse well and dry with paper towel

Use paper towel to close taps (if old type)

Front 579

Explain the uses of alcohol hand sanitisers

Back 579

Convenient, dries quickly

10 – 15 sec application

Less irritating than hand washing

No good if hands visibly soiled

no goof for proteinaceous material

Be careful during diarrhoea outbreaks, glove, wash hands after degloving

Front 580

narrow-spectrum antibiotics

Back 580

effective on specific target organisms

leave more of the microbial flora intact

Front 581

broad spectrum antibiotics

Back 581

effectiveon several groups of microbes

disrupt microbial flora of host

Front 582

Identify the bacterial processes to which antibiotic action can affect the growth of bacteria

Back 582

-inhibition of cell wall synthesis

-inhibition of protein synthesis

-inhibition of nucleic acid replication and transcription

-inhibition of synthesis of essential metabolites

-injury to plasma membrane

Front 583

List ways in which bacteria may become resistant to antibiotics

Back 583

- bacteria that produce antibiotics have mechanisms to resist theirown antibiotics

- These resistance genes can betransferred to other microbes

- Penicillin-resistant bacteria producethe enzyme b-lactamase,cleave the b-lactamring of penicillins

- Many microbes become resistant tosulfa drugs by taking up folic acid from the environment instead ofsynthesising it

- Some microorganisms have activemechanisms (efflux pumps) for removing antimicrobials

Front 584

Give examples of where the preparation of a disinfectant can be important

Back 584

Mustknow the chemical before using it, e.g:

safety precautions,

optimal strength

Front 585

Distilation formula

Back 585

Front 586

therapeutic index

Back 586

thehigher the TI, the better the drug

effectiveness:toxicity

Front 587

Describe how the structure of penicillin was used to make semi-synthetic derivatives

Back 587

1. the R group was modified for different results

Front 588

how bacteria exploited the structure of penicillin to become resistant to penicillin

Back 588

b-lactam ring is susceptible to the enzyme b-lactamase,

they cleave the b-lactam ring of penicillins

Front 589

what is the active part of penicillin

Back 589

b-lactam ring

beta-lactam ring

Front 590

Following a microbiology practical class the bench is wiped down with sodium hypochlorite. The best description of the result will be to:

a) Kill all viable cells and spores

b) Kill all viable cells but spores may survive

c) Reduce viable microorganisms to a safe level

d) Slow the growth of microorganisms

e)Destroy most microbes but some pathogens may survive

Back 590

b) Kill all viable cells but spores may survive

Front 591

Which is more effective 70% ethanol or 95% ethanol?

a) 70% ethanol as it contains water which improves its effectiveness

b) They both have the same effectiveness

c) 95% ethanol as it is more concentrated

d) 70% ethanol as it is more concentrated

d) 95% as it is pure alcohol

Back 591

a) 70% ethanol as it contains water which improves its effectiveness

Front 592

Chi Square Test:

Back 592

used todetermine whether there is a significant association between the two variables.

·Degrees of freedom.

· Expected frequencies.

· Test statistic.

· P-value.

Front 593

Degrees of freedom.

Chi squared test

Back 593

1. DF = (r - 1) * (c - 1)

r is the number of levels for one catagorical variable,

c is the number of levels for the other categorical variable.

Front 594

Expected frequencies.

Chi squared test

Back 594

Er,c = (nr * nc) / n

Er,c is the expected frequency count for level r of Variable A and level c of Variable B,

nr is the total number of sample observations at level r of Variable A,

nc is the total number of sample observations at level c of Variable B,

n is the total sample size.

Front 595

Test statistic.

Chi squared test

Back 595

Χ2 = Σ [ (Or,c - Er,c)2 /Er,c ]

Or,c isthe observed frequency count at level r ofVariable A and level c ofVariable B,

Er,c is the expected frequency count atlevel r ofVariable A and level c ofVariable B.

Front 596

P-value

chi squared test

Back 596

probability of observing a sample statistic as extreme as the test statistic.

Since the test statistic is a chi-square, use the Chi-Square Distribution Calculator to assess the probability associated with the test statistic.

Use the degrees of freedom computed above.

Front 597

Back 597

1. Chi squared chart

Front 598

formation of peptide bond

Back 598

a chemical bond formed betweentwo molecules

when the carboxyl group of one molecule reacts with the aminogroup of the other molecule,

releasing a molecule of water (H2O).

Front 599

molecular structure of proteins:

Back 599

primary structure (polypeptide chain),

secondary structure (α-helix),

tertiary structure (folding of polypeptide);

quaternary structure (binding of different polypeptides)

Front 600

formation of peptide bond

Back 600

a chemical bond formed between two molecules

when the carboxyl group of one molecule reacts with the amino group of the other molecule,

releasing a molecule of water (H2O).

Front 601

secondary structure of proteins

Back 601

3. α-helix

Front 602

tertiary structure of proteins

Back 602

3. folding of polypeptide

Front 603

quaternary structure

Back 603

3. (binding ofdifferent polypeptides/proteins

Front 604

Test statistic.

Chi squared test

Back 604

Χ2 = Σ [ (Or,c - Er,c)2 /Er,c ]

Or,c is the observed frequency count at level r of Variable A and level c of variable B,

Er,c is the expected frequency count at level r of Variable A and level c of variable B.

Front 605

Properties of Genetic Code

Back 605

triplet,

continuous,

non-overlapping,

universal,

degenerate

redundant

Front 606

The most commontype of mucosal immunoglobulin is:

(a) IgG

(b) IgM

(c) IgD

(d) IgA

(e) IgE

Back 606

(d) IgA

Front 607

The antibody associated with allergy is:

(a) IgG

(b) IgM

(c) IgD

(d) IgA

(e) IgE

Back 607

(e) IgE

Front 608

An epitope:

(a) is recognised by the Fab regions of anantibody

(b) is formed by light and heavy chain of an antibody

(c) is the same for every antibody of a given immunoglobulin class

(d) can only bind an antigen when the antibody has been secreted

(e) none of the above

Back 608

(a) is recognised by the Fab regions of an antibody

Front 609

Which of the following is/aretrue of IgM?

(a) It has only two antigen binding sites

(b) It is necessary for the effective action of IgG

(c) It can exist as a pentamer

(d) (a), (b) and (c)

(e) none of the above

Back 609

(c) It can exist as a pentamer

Front 610

The firstantibody produced in response to an antigenic stimulus is:

(a) IgG

(b) IgM

(c) IgE

(d) IgD

(e) IgA

Back 610

(b) IgM

Front 611

Antibodiesof differing specificity are generated by:

(a) rearrangement of gene segments

(b) having millions of genes encoding antibody chains

(c) somatic mutation of antibody genes

(d) (a) and (c) above

(e) (b) and (c) above

Back 611

(d) (a) and (c) above

There are not millions of whole genes

rather millions of segments than can be selected and sliced in areas of the genome.

Front 612

Cytotoxic T cells (Tc cells) will recognise viral antigens providing they are:

(a) bound by the Class I MHC molecule

(b) bound by the Class II MHC molecule

(c) independent of any MHC recognition site

(d) bound to any MHC molecule

(e) not bound to any MHC molecule

Back 612

(a) bound by the Class I MHC molecule

Front 613

Which trait(s) are true aboutmacrophages?

(a) they serve as antigen presenting cells

(b) they are non-specific

(c) they serve as antigen-processing cells

(d) all of the above

(e) none of the above

Back 613

(d) all of the above

Front 614

Which statement is true of T lymphocytes?

(a) they produce lymphokines (cytokines)

(b) they mature in the bone marrow

(c) all T- lymphocytes have both the CD4 andCD8 surface protein

(d) only cytotoxic T lymphocytes can help B cells to produceantibody

(e) all of the above are true

Back 614

(a) they produce lymphokines (cytokines)

Front 615

Class II MHC proteins are foundon the surface of:

(a) all nucleated cells

(b) B lymphocytes only

(c) macrophages and dendritic cells

(d) B lymphocytes, macrophages and dendritic cells

(e) red blood cells

Back 615

(d) B lymphocytes, macrophages and dendritic cells

B cells also act as antigen presenting cells

sohave MHC11 molecules that present antigen

Front 616

Experiment that let to deciphering of Genetic Codes

Back 616

Nirenberg & Khorana – 1961

synthesised artificial mRNA

-added lysate whichsynthesised protein

polyU mRNA translated topoly-phenylalanine

‘UUU’ codes for‘phenylalanine’

Front 617

3. Nirenberg & Khorana – 1961

Back 617

3. synthesised artificial mRNA-added lysate whichsynthesised proteinpolyU mRNA translated topoly-phenylalanine‘UUU’ codes for‘phenylalanine’

Front 618

An epitope:

(a) is recognised by the Fab regions of an antibody

(b) is formed by light and heavy chain of an antibody

(c) is the same for every antibody of a given immunoglobulin class

(d) can only bind an antigen when the antibody has been secreted

(e) none of the above

Back 618

(a) is recognised by the Fab regions of an antibody

Front 619

Cellular immunity

Back 619

- Mediatedby specialised cells

-T cells

Front 620

The first antibody produced in response to an antigenic stimulus is:

(a) IgG

(b) IgM

(c) IgE

(d) IgD

(e) IgA

Back 620

(b) IgM

Front 621

epitope

Back 621

-thepart of an antigen that is recognised

-Each antigen cancontain several epitopes: multivalent antigens

Front 622

antigen

Back 622

1. substancesthat induce an immune response

Front 623

multivalent antigens

Back 623

1. antigenwith multiple epitopes

Front 624

Draw IgG,

Back 624

Front 625

Draw IgM

Back 625

Front 626

Draw IgA

Back 626

Front 627

3. Nirenberg & Khorana – 1961

Back 627

3. synthesised artificial mRNA

-added lysate which synthesised protein poly? mRNA translated to poly-phenylalanine‘ UUU’ codes for ‘phenylalanine’

Front 628

1. Pedigree Analysis,

Back 628

familytree across generations

Front 629

1. Are humans a model genetic organism

Back 629

no

Front 630

1. why pedigreeanalysis is often difficult to construct

Back 630

-records are incomplete

-cannot get reliable information about the deceased

-reluctance to discuss personal information

-abortions, artificial inseminations, illegitimate births are hard to account for

-variable phenotypic expression (variable expressivity) affects information collected

Front 631

epitope

Back 631

-the part of an antigen that is recognised

-Each antigen can contain several epitopes: multivalent antigens

Front 632

Back 632

1. Family pedigree

Front 633

multivalent antigens

Back 633

1. antigen with multiple epitopes

Front 634

1. How individualsare identified in family pedigrees

Back 634

- Arabic numerals

- individualswithin a generation numbered in birth order

Front 635

1. Males

– family pedigree symbols

Back 635

- squares

Front 636

Back 636

- Males

- family pedigree symbols

Front 637

Females

- familypedigree symbols

Back 637

circles

Front 638

Back 638

- Female

- family pedigree symbols

Front 639

- Sex unknown or unspecified

- familypedigree symbols

Back 639

–diamond

Front 640

Back 640

Sex unknown or unspecified

- familypedigree symbols

Front 641

- Sex unknown or unspecified

- family pedigree symbols

Back 641

–diamond

Front 642

Back 642

- Stillbirths,miscarriages, abortions

- family pedigree symbols

Front 643

- Deceased

- family pedigree symbols

Back 643

line through

Front 644

Back 644

Deceased

- family pedigree symbols

Front 645

- Proband

- familypedigree symbols

Back 645

-the individual through whom the pedigree was discovered

– denoted by arrow

Front 646

Back 646

- Proband

- the individual through whom the pedigree was discovered

- family pedigree symbols

Front 647

Females

- family pedigree symbols

Back 647

circles

Front 648

- unaffectedindividuals

- family pedigree symbols

Back 648

opensymbols

Front 649

characteristics of acquired immunity

Back 649

Specificimmunity that develops after exposure to an antigen,

or after transferof antibodies or cells from an immune donor

Front 650

Cellular immunity

Back 650

Mediatedby specialised cells

-T cells

Front 651

humoral immunity

Back 651

Antibody mediated

-B cells

Front 652

epitope

Back 652

-thepart of an antigen that is recognised

-Each antigen cancontain several epitopes:

-multivalent antigens

Front 653

antigen

Back 653

1. substancesthat induce an immune response

Front 654

multivalent antigens

Back 654

1. antigenwith multiple epitopes

Front 655

Draw IgG,

Back 655

Front 656

Draw IgM

Back 656

Front 657

Draw IgA

Back 657

Front 658

1. Where is a genelocated on a chromosome?

Back 658

1. at a particular locus

Front 659

1. Where arealternate forms of the gene (allele)

Back 659

1. at the same locus on the homologous chromosome.

Front 660

1. How many allelesfor a gene can exist

Back 660

1. Multiple

Front 661

1. Allelic forms ofa gene result from?

Back 661

1. mutation in that gene.

Front 662

1. Name for thenormal form of gene

Back 662

wild type

Front 663

1. Is the wild typeof an allele dominant or recessive

Back 663

1. dominant

Front 664

1. Is the mutatedform of an allele dominant or recessive

Back 664

1. Recessive

Front 665

1. how to calculatenumber of homozygotes, heterozygotes and genotypes that are possible from agiven number of alleles (n)

Back 665

Alleles = n

genotypes = n(n+1/2)

homozygotes = n

heterozygotes= n(n-1)/2

Front 666

1. How to calculatenumber of genotypes from number of alleles (n)

Back 666

1. n(n+1)/2

Front 667

1. How to calculatenumber of homozygotes from number of alleles (n)

Back 667

n

Front 668

1. How to calculatenumber of hetrozygotes from number of alleles (n)

Back 668

1. N(n-1)/2

Front 669

In gremlins, coatcolour is determined by a gene with multiple alleles.

The three allelesinvolved are: B (brown colour); b (white colour); and ba (brown andwhite stripes).

For this locus, B is dominant to both b and ba , and ba is dominantto b.

In a cross between a B/ba male gremlin and a B/b femalegremlin, what percentage of the offspring will have brown and white stripes?

a) 0

b) 25

c) 50

d) 100

Back 669

b) 25

Front 670

For any gene withmultiple alleles, a diploid organism may have a maximum of ________ alleles forthat locus.

a) 1

b) 2

c) 6

d) 10

e) 100

Back 670

b) 2

Front 671

Which of thefollowing traits is determined by a gene with multiple alleles?

a) ABOblood groups in humans

b) eyecolour in Drosophila

c) HLAtypes in humans

d) allof the above

e) noneof the above

Back 671

d) all of the above

Front 672

A person with typeA blood could have which genotype?

a) IA/IA

b) IA/i

c) i/i

d) bothA and B

e) allof the above

Back 672

d) both A and B

Front 673

For traits thatshow incomplete dominance, the phenotype of a heterozygote is

a) thesame as the homozygous dominant phenotype.

b) thesame as the homozygous recessive phenotype.

c) intermediatebetween the homozygous dominant and homozygous recessive phenotypes.

d) completelydifferent from either the homozygous dominant or recessive phenotype.

Back 673

c) intermediate between the homozygous dominant and homozygous recessive phenotypes.

Front 674

Flower colour insnapdragons is a trait showing incomplete dominance. Therefore, the flowers ofa snapdragon plant that is the offspring of a cross between a plant with red flowersand one with white flowers would be

a) red.

b) white.

c) pink.

d) somered and some white.

e) redwith white spots.

Back 674

c) pink.

Front 675

In a certain typeof plant, the gene for flower colour has two alleles, blue and yellow.Heterozygous plants produce green flowers. This is an example of

a) incompletedominance.

b) codominance.

c) completedominance.

d) partialdominance.

e) epistasis.

Back 675

a) incomplete dominance.

Front 676

New phenotypes thatchange the expected phenotypic ratios for a trait can result when

a) differentgenes interact.

b) oneallele is dominant to another.

c) agene has more than two alleles.

d) bothA and C

e) allof the above

Back 676

d) both A and C

Front 677

The expressivity ofa gene depends on the organism's

a) genotype.

b) gender.

c) age.

d) environment.

e) allof the above

Back 677

e) all of the above

Front 678

A(n) ________ genemasks the expression of a different, nonallelic gene.

a) incompletelydominant

b) epistatic

c) recessive

d) codominant

e) hemizygous

Back 678

b) epistatic

Front 679

A mutation in anessential gene

a) willmodify a phenotype.

b) isgenerally lethal to the organism.

c) suppressesthe activity of other genes.

d) hasno apparent effect on the organism.

Back 679

b) is generally lethal to the organism.

Front 680

A(n) ________allele causes the death of the individual that carries it.

a) recessive

b) epistatic

c) penetrant

d) lethal

e) codominant

Back 680

d) lethal

Front 681

A person who isknown to have a particular genotype does not show the phenotype specified bythe gene. This is an example of

a) incompletedominance.

b) epistasis.

c) incompletepenetrance.

d) phenotypeswitching.

e) sexreversal.

Back 681

c) incomplete penetrance.

Front 682

Members of a familyhave a condition in which the second toe is longer than the big toe. The traitis found in every generation, but it doesn't always appear in family memberswith the associated genotype. In some people, the second toe is longer on bothfeet; in others only one foot has the affected toe. This gene is

a) dominant.

b) incompletelypenetrant.

c) variablyexpressed.

d) allof the above

e) noneof the above

Back 682

d) all of the above

Front 683

Some fruit fliesthat are homozygous for the recessive eyeless gene have no eyes, while othershave eyes that are smaller than normal. Still others have completely normaleyes. This indicates that the eyeless gene is

a) epistatic.

b) completelypenetrant.

c) codominant.

d) incompletelydominant.

e) variablyexpressed.

Back 683

e) variably expressed.

Front 684

Autosomal traits thatappear in both genders but differ between males and females either in frequencyof occurrence or in phenotype are

a) sexlinked.

b) sexinfluenced.

c) sexdependent.

d) sexinhibited.

e) sexlimited.

Back 684

c) sex limited.

Front 685

In a biochemicalpathway, the product of gene A converts a colourless substance into a yellowsubstance, which in turn is converted by the product of gene B into a greenpigment. Although the organism is normally green, a mutation inactivates gene Band the yellow substance accumulates. Gene A and gene B are

a) codominant.

b) phenocopies.

c) epistatic.

d) holandric.

e) lethal.

Back 685

c) epistatic.

Front 686

Autosomal traitsthat appear only in one gender are

a) sexlinked.

b) sexinfluenced.

c) sexlimited.

d) sexinhibited.

Back 686

c) sex limited.

Front 687

The degree to whichsymptoms occur in people with the genetic disorder phenylketonuria dependsmostly on the affected person's

a) age.

b) diet.

c) gender.

d) allof the above.

e) noneof the above

Back 687

b) diet.

Front 688

A person with typeB blood could receive a transfusion of blood from someone with blood type

a) B

b) AB

c) O

d) bothA and C

e) allof the above

Back 688

d) both A and C

Front 689

In a biochemicalpathway, the product of gene A converts a colourless substance into a yellowsubstance, which in turn is converted by the product of gene B into a greenpigment. Although the organism is normally green, a mutation inactivates gene Band the yellow substance accumulates. Gene A and gene B are

a) codominant.

b) phenocopies.

c) epistatic.

d) holandric.

e) lethal.

Back 689

c) epistatic.

Front 690

A man with bloodtype A and a woman with blood type B could never produce a child with bloodtype

a) A

b) B

c) AB

d) O

e) noneof the above

Back 690

e) none of the above

Front 691

A person who washomozygous for the recessive mutant allele h, and was IAi at the ABO locus,would have which blood type?

a) A

b) B

c) AB

d) O

Back 691

d) O

Front 692

Which gene isresponsible for the expression of blood group antigens on the surface of redblood cells?

a) B

b) A

c) H

d) I

Back 692

c) H

Front 693

The probabilitythat two parents will have 3 girls and 1 boy in their family is?

a) 1/4

b) 1/2

c) 1/8

d) 1/16

Back 693

d) 1/16

Front 694

What is theprobability that the first child of two parents is a girl?

a) 1/2

b) 1/4

c) 1/8

d) 1/16

Back 694

a) 1/2

Front 695

A person with typeO blood carries antibodies for ________ in his (her) blood

a) A

b) B

c) bothA and B

d) O

Back 695

c) both A and B

Front 696

The genotype for aperson with type O blood is ________

a) IA/IB

b) IA/i

c) IB/i

d) i/i

Back 696

d) i/i

Front 697

The serum of aperson with type A blood will contain antibodies against which antigen?

a) Aonly

b) Bonly

c) bothA and B

d) O

Back 697

b) B only

Front 698

The serum of aperson with type A blood will contain antibodies against which antigen?

a) Aonly

b) Bonly

c) bothA and B

d) O

Back 698

b) B only

Front 699

Epistasis

Back 699

-One gene (pair of allele) masks expression of another gene (pair of allele)

-Epistasis may be caused because of presence of dominant allele or both recessive alleles of one gene

-Epistasis can also occur in both directions between two pairs of alleles of two genes

Front 700

1. Are Mendelianratios changed due to epistasis?

Back 700

Yes.

Varies for where the epistasis occurs/behaves

Front 701

1. what happens whenrecessive ‘b’ (b/b) is epistatic to ‘A’ or ‘a’?

Back 701

1. 3 ‘A/- b/b’ and 1 ‘a/a b/b’ produce the same phenotype

F2 ratio is modified to 9:3:4.

Front 702

1. what happens whendominant ‘A’ (A/-) is epistatic to ‘B’ or ‘b’?

Back 702

9 ‘A/- B/-’ and 3 ‘A/- b/b’ produce the same phenotype.

F2 ratio is modified to 12:3:1.

Front 703

1. Duplicategenes:

Back 703

two genes produce identical phenotype

meaning, gene/genotype at one locus produces same phenotype as gene/genotype at other locus

Front 704

1. what happens when recessive ‘a’ (a/a) is epistatic to ‘B’ or ‘b’ and recessive ‘b’ (b/b) is epistatic to ‘A’ or ‘a’?

Our A/- and B/- produce same phenotype

Back 704

1. ‘A/- b/b’, ‘a/a B/-’, ‘a/a b/b’ will all have same phenotype

F2 phenotypic ratio is modified to 9:7

Front 705

what happens when dominant ‘A’ (A/-) is epistatic to ‘B’ or ‘b’

and dominant ‘B’ (B/-) is epistatic to ‘A’ or ‘a’? 1.

Back 705

9 ‘A/- B/-’, 3 ‘A/- b/b’, 3 ‘a/a B/-’ produce the same phenotype.

F2 ratio is modified to 15:1.

Front 706

1ml to um

Back 706

1000um

Front 707

1000 um to ml

Back 707

1 ml

Front 708

100 um to ml

Back 708

0.1 ml

Front 709

10 um to ml

Back 709

0.01 ml

Front 710

1 um to ml

Back 710

0.001 ml

Front 711

1 liter in ml

Back 711

1000 ml

Front 712

times 10

Scientific notation

Back 712

x10

Front 713

times 100

Scientific notation

Back 713

x102

Front 714

times 1000

Scientific notation

Back 714

x103

Front 715

IgG,

Back 715

Immunoglobulin,

Monomer,

enhances phagocytosis,

neutralizes toxins and viruses,

protects foetus and newborn

Front 716

IgM

Back 716

Immunoglobulin,

Pentamer,

Especially effective against microorganisms and agglutinating antigens,

first antibodies produced in response to initial infection

Front 717

IgA

Back 717

Immunoglobulin,

dimer (with secretory component),

localised protection on mucosal surfaces

Front 718

B cells

Back 718

Antibodiesare produced by B cells

Beforeactivation, the immunoglobulin is a B cell receptorB

cells originateand mature in the bone marrow (and the foetal liver)

Front 719

Explain how antibodies are formed

Back 719

1. Antibodiesare produced by B cells

Front 720

Describe how it is possible to form antibody for every possible antigen that could exist

Back 720

Rearrangementof gene segments

Somaticmutations

Generation ofdifferent codons during gene splicing

Front 721

T cells

Back 721

Tcells have a specific, but highly diverse receptor;

T cells mature in the thymus

haveantigen-specific T-cell receptors (TCRs) on their surface;

Do not recognisenative antigen,

but recognise antigen “presented” by another cell (antigenpresenting cell, APC)

Front 722

Explain how antibody production requires the assistance of helper T cells

Back 722

Inorder for a B cell to be fully activated, it must interact with a certain classof T cells

Another class of Tcells is required for the elimination of infected cells

Front 723

A toxin is mixed with an antibody.

You would expect the toxin to be:

(a) neutralized

(b) agglutinated

(c) opsonized

(d) precipitated

(e) haemagglutinated

Back 723

(a) neutralized

Front 724

In the complement fixation test you would expect bacteria to be:

(a) neutralized

(b) agglutinated

(c) opsonized

(d) precipitated

(e) haemagglutinated

Back 724

(c) opsonized

Front 725

In a test involving agar immunodiffusion you would expect to see antigen:

(a) neutralized

(b) agglutinated

(c) opsonized

(d) precipitated

(e) haemagglutinated

Back 725

(d) precipitated

Front 726

In blood typing you would expect red blood cells to be:

(a) neutralized

(b) agglutinated

(c) opsonized

(d) precipitated

(e) haemagglutinated

Back 726

(b) agglutinated

Front 727

Influenza virus is mixed with erythrocytes causing them to be:

(a) neutralized

(b) agglutinated

(c) opsonized

(d) precipitated

(e) haemagglutinated

Back 727

(e) haemagglutinated

Front 728

A monoclonal antibody could be used as:

(a) passive protection against infection

(b) active protection against infection

(c) treatment for cancer

(d) all of the above

(e) (a) and (c) above

Back 728

(e) (a) and (c) above

Front 729

In the first step of a directELISA test for antigen:

(a) a glass slide is stained with a fluorescentantibody

(b) a latex antibody solution is added to seeif agglutination takes place

(c) wells of a microtiter tray are coatedwith antibody

(d) cells bearing antigen are counted in afluorescent sorter

(e) proteins are separated by size using electrophoresis

Back 729

(c) wells of a microtiter tray are coated with antibody

Front 730

Fluorescent antibodies may be useful to:

(a) microscopically visualise a difficult to culture organism

(b) label helper T cells and enable them to be counted

(c) identify the cause of an infection microscopically

(d) all of the above

(e) none of the above

Back 730

(d) all of the above

Front 731

A good screening test:

(a) must not have any false positives

(b) should have high sensitivity but may have lower specificity

(c) should have high specificity but may have lower sensitivity

(d) should always be confirmed with a second test

(e) will rapidly confirm positive results

Back 731

(b) should have high sensitivity but may have lower specificity

Front 732

Western blots are used to:

(a) confirm HIV screening tests

(b) measure immunofluorescence

(c) count CD4 cells

(d) show whether agglutination as occurred

(e) rapidly screen patients

Back 732

(a) confirm HIV screening tests

Front 733

serology

Back 733

the observation of antibody-antigen reactions invitro

Front 734

neutralisation

Back 734

-Antibodies attach to the outside of antigens

-Blocks adhesion of bacteria and viruses to mucosa

-blocks attachment of toxin

Front 735

agglutination

Back 735

-Thisoccurs when the crosslinked particles precipitate.

•Antibodies binding to particles can cause them to clumpIn vivo,

-these are quickly cleared by immune cells

• Visibleto the naked eyeveryuseful for diagnosis

•Principle behind blood-typing

Front 736

precipitation,

Back 736

Antibodies bind to antigen and link them together,

-forming a precipitate

Front 737

opsonisation

Back 737

apathogen is marked for ingestion and eliminated by a phagocyte.

- Afteropsonin binds to the membrane, phagocytes are attracted to the pathogen

Front 738

opsonin

Back 738

anymolecule that enhances phagocytosis by marking an antigen for immune destruction

Front 739

haemagglutination

Back 739

the clumping together of red blood cells.

Viruses such as influenza have surface proteins that act as haemagglutins

Front 740

Haemagglutination inhibition

Back 740

- Antiviral antibodies attach to viruses

-viruses are thus neutralizes and hemagglutination is inhibited

Front 741

monoclonal antibodies

Back 741

- the antibody derived from a single B-cell clone (single cell lineage)

• After infection with a pathogen, a polyclonal serum is generated

• Defined specificity

• Single class (Usually IgG)

• Highly reproducible

• Can get several MAs to the same antigen

• Immortal!

Front 742

Polyclonal antibodies

Back 742

antibodies that are secreted by different B cell lineages within the body

-(whereas monoclonal antibodies come from a single cell lineage).

-After a monyclonal antibody has an infection with a pathogen, a polyclonal serum is generated

Front 743

1. Penetrance

Back 743

thepercentage of individuals with a genotype who exhibit the phenotype associatedwith the genotype

Front 744

Expressivity

Back 744

1. degree to which a penetrant gene isphenotypically expressed in an individual

Front 745

1. Is expressivityfor an individual or a population

Back 745

1. individual

Front 746

1. Is penetrance foran individual or a population

Back 746

1. population

Front 747

1. What are thefactors that result in different Penetrance of genotypes

Back 747

Environmental factors :

Age of Onset:

Sex:

Chemicals:

Temperature:

Front 748

1. What are thefactors that result in different Expressivity of genotypes?

Back 748

Environmental factors :

Age of Onset:

Sex:

Chemicals:

Temperature:

Front 749

How would you determine the number of genes involved in a set of mutation with same phenotype

Back 749

1. If mutation in different genes: they can complement each other

If mutation is same gene: no complementation!

Front 750

1. Complementationtest (cis-trans test).

Back 750

Front 751

how eukaryotic chromosomes segregate (separate) during gamete formation

Back 751

- through meiosis.

– random assortment of chromosomes

Front 752

crossing-over in meiosis

Back 752

1. chromosomes switch chunks of DNA

Front 753

Different sex determination systems:

Back 753

XX-XY’, - mammals

‘XX-XO’ – many insects

‘ZZ-ZW’ – birds and some fish

haplo-diploid – plants

Front 754

environmentalsex determination

Back 754

- sequential hermaphroditism

-, sex is determined fully or in part by environmental factors.

- each individual animal can be both male and female, although not at the same time.

– temperature and proximity to other individuals influence this

Front 755

XX-XY

Back 755

- operates in mammals, drosophila

Male (XY)

Female (XX)

Front 756

XX-XO

Back 756

- Protenor system

– many insects

- female has two copies of sex chromosome

male has only one sex chromosome

Female - XX

Male - XO

Front 757

ZZ-ZW’

Back 757

operates in birds and some fish

males– ZZ

females– ZW

Front 758

haplo-diploid systems

Back 758

- sex determination by one gene (two alleles) in plants

-chomosomes that carry the sex determining region pair along entire length

-typically one sex is heterozygous and the other is homozygous

Front 759

ELISA

Back 759

Enzyme-Linked Immunosorbent Assay

• Very sensitive detection technique

• Relies on enzymes attached to antibodies

• Two types:

– Direct

– Indirect

Front 760

Sandwich ELISA process

Back 760

(1) Plate is coated with a capture antibody;

(2) sample is added, and any antigen present binds to capture antibody;

(3) detecting antibody is added, and binds to antigen;

(4) enzyme-linked secondary antibody is added, and binds to detecting antibody;

(5) substrate is added, and is converted by enzyme to detectable form

Front 761

screening test

Back 761

A good screening test should have high sensitivity (not miss any positives)

A trade off is specificity

Front 762

confirmatory test

Back 762

7. Specific test for target antigens

Front 763

Explain what happens in a ‘Western Blot’

Back 763

1) Electrophoresis is used to separateproteins in the serum which move based on charge and size.

2) The bands ofprotein are transferred to a nitrocellulose filter by blotting.

3) The filteris washed with the patients serum followed by anti-human antibodies tagged withan enzyme, making the antibodies visible.

4. The test is read. Taggedantibodies stick to the filter and can be seen.

Front 764

Explain how T helper cells might be counted

Back 764

T-helper cells have protein receptor CD4

Make antibodies to CD4 and tag with a charge or fluorescence

Mix with patient’s blood and pass through cell-counting machine

Count the signals to give cell count

Front 765

Describe how fluorescent antibodies might be used

Back 765

Fluorescent microscopes can be used toimage antibody interactions when antibodies are tagged with fluorescent dyes

Cells canbe separated using flow cytometry