Micro Lab Quiz Iii

Front 1

psychorphiles

Back 1

grow at temperatures below 0 to 15C

Front 2

Mesophiles

Back 2

grow between ~15-45C

Front 3

Thermophiles

Back 3

grow between 40-80C

Front 4

Hyperthermophiles

Back 4

grow above 100C

Front 5

Minimum growth temp

Back 5

the cells are growing but it is so slow that it is incompatible with survival

Front 6

Maximum growth temp

Back 6

a steady decline from the optimum growth temperature

Front 7

Optimal growth temperature

Back 7

cells are most comfortable, as evident with their growth rate.

Front 8

when an organism gets towards maximum growth temp, what can happen to the cells macromolecules

Back 8

denaturation can occur

Front 9

Which of the species used in this exercise would you expect to be most likely to cause spoilage of refrigerated food?

Back 9

Arthrobacter

Front 10

what species from Lab 10 would be able to grow most rapidly in the human body?

Back 10

Micrococcus and E.coli because it has the highest growth avg. for 37C

Front 11

what is osmosis

Back 11

the process in which water flows from one side to the other of a semi-permeable membrane.

Front 12

what is the force that drives osmosis?

Back 12

the movement of water molecules is driven by osmotic pressure.

Front 13

what directs the diffusion of water during osmosis

Back 13

water will flow depending ont he difference in the concentration of water molecules between both sides of the membrane. (will flow to a side with lower water concentration)

also it is attracted to places with a lower solute concentration.

Front 14

what are the three enviornments a microbe can experience with regards to osmotic pressure

Back 14

Isotonic
Hypertonic
Hypotonic

Front 15

what is an isotonic environment

Back 15

there is no net flow of water across the membrane because there is an equal concentration of solutes inside and outside.

Front 16

what is a hypertonic environment?

Back 16

environment were there is much higher concentration of solutes outside the cell than inside.
water will flow out draining the cell of water.

Front 17

what will happen to the cell during a hypertonic environment

Back 17

the plasma membrane will shrink which is known as plasmolysis.

Front 18

define halotolerant

Back 18

can grow at low to moderate salt concentrations

Front 19

what are halophiles

Back 19

actually require the high salt environment for growth.

Front 20

define hypotonic environment

Back 20

much lower of concentration of solutes outside the cell than inside.

water will from the outside to the in which will lyse the cell.

Front 21

what is a neutral solution (in terms of pH)

Back 21

7.0
has an equal amount of protons and hydroxyl ions

Front 22

what is an acidic solution (pH)

Back 22

0-6.99
has an excess of protons or a deficiency of hydroxyl ions

Front 23

what is an alkaline solutions (pH)

Back 23

7.01-14
have excess hydroxyl ions or a deficiency of protons

Front 24

relativity of the pH scale and protons

Back 24

a change of one number on the pH scale is equivalent to a 10-fold increase/decrease in the number of protons

Front 25

how can an acidic solution reduce its pH

Back 25

acid can donate its protons to water (if it is added to water) which can reduce its pH

Front 26

how can an alkali solution increase its pH?

Back 26

if added to water, the hydroxyl can donate its ions to the water, increasing its pH

Front 27

environment acidophiles live in

Back 27

acidic, low pH environments

Front 28

alkaliphiles environment

Back 28

live in high pH environments

Front 29

environment for neutralophiles

Back 29

live at near neutral pH levels.

Front 30

define strict aerobes

Back 30

micrococcus species, have an absolute requirement for oxygen and depend on aerobic respiration for growth

Front 31

strict anaerobes

Back 31

the clostridium species
for some of these organisms, exposure to O2 is fatal, they depend on anaerobic respiration and/or fermentation for growth

Front 32

Facultative mcirobes

Back 32

are a very adaptable class of microbes where they can grow either int eh presence or absence of oxygen (aerobic respiration or anaerobic/fermentation)

Front 33

how do you grow microbes that cannot grow in an aerobic environment?

Back 33

use thioglycollate media

it is a reducing agent that effectively removes oxygen from the environment.

Front 34

why is thioglycollate a good media for anaerobic growth?

Back 34

it reacts with and sequesters the oxygen in the media.


and oxygen gradient is established - the portion at the interface between the air and the medium is somewhat aerobic while the deeper regions become increasingly anerobic.

Front 35

what is resazarin?

Back 35

an indicator for the amount of oxygen in a thioglycollate broth tube - should be colorless in anaerobic conditions, and will turn pink if it is exposed to oxygen.

Front 36

what are cidal agents?

Back 36

a chemical which prevents growth through permanent destruction of a cell

Front 37

static agents?

Back 37

a chemical which prevents growth by slowing or stoping growth but if the agent is removed, growth may resume.

Front 38

what's a sterilant?

Back 38

sterilization is a term used to describe the destruction of al organisms in or on something.

this includes all organisms on a surface or in a fluid.

Front 39

What's a disinfectant

Back 39

used to describe processes that lead to the reduction in the number of pathogens to harmless levels.

Front 40

if an object is disinfected, is it sterilized?

Back 40

no, it is just no longer capable of causing disease.

Front 41

are disinfectants ok to use on body?

Back 41

no they are too harsh to use on tissues, reserved to cleaning surfaces.

and they do not destroy bacterial endospores

Front 42

what are antseptics give an example

Back 42

a chemical that is used on tissue to destroy or inhibit the growth of microorganisms.

an example would be hydrogen peroxide which will effectively clean a cut but it will cause moderate tissue damage.

Front 43

define santization

Back 43

the process of removing microorganisms to reduce contamination to safe levels.

Front 44

what is a phenol coefficient

Back 44

quantitative assessment of the effectiveness of a compound as a disinfectant.

Front 45

look over phenol coefficient paragraph from antiseptic lab

Back 45

-

Front 46

how do soaps and detergents work in preventing growth

Back 46

work by dissolving the plasma membrane

Front 47

how do halogens prevent growth and give examples of halogens

Back 47

denature proteins.

ex. is iodine and chlorine

Front 48

how do alcohols prevent growth and give examples

Back 48

dissolving the plasma membrane and can denature proteins.

ex. isopropanol (rubbing alcohol) and ethanol.

Front 49

How do phenolics prevent growth and give examples

Back 49

dissolve the plasma membrane and denature proteins.

ex. lysol, pHisoHex hand wash

Front 50

how do oxidizing agents prevent growth and give examples

Back 50

oxidation of biological macromolecules

ex. hydrogen peroxide.

Front 51

what's an antibiotic

Back 51

a chemical that exhibits the property of selective toxicity (a chemical that is poisonous to a microbe yet harmless to the human or animal host)

Front 52

what is the principle of selective toxicity

Back 52

it exploits the differences in cellular structure and metabolic pathways that exist between animal host and the infectious agnet

Front 53

what is the key difference between antiseptics/disinfectants and antibiotics

Back 53

selective toxicity: while all agents are toxic to bacterial and human cells, only antibiotics preferentially target bacteria.

Front 54

what are the two effects antibiotics have?

Back 54

-static
-cidal effect

Front 55

bacteriostatic drugs

Back 55

slow the growth of organisms but do not kill organisms

Front 56

bactericidal drugs

Back 56

kill the organism and are usually more effective on actively growing cells.

Front 57

how is the effectiveness of an antibiotic described

Back 57

it can be described in terms of its
spectrum and
sensitivity/resistance of the bacterial pathogen to a particular antibiotic.

Front 58

what is the antibiotic spectrum

Back 58

describes the range of species that are sensitive to the antibiotic

there are "broad" and "narrow" range antibiotics

Front 59

sensitivity/resistance for describing antibiotic effectivness

Back 59

whether or not particular bacterium can be inhibited or killed by the drug

Front 60

effective antibiotic treatment requires the bacterium to be sensitive to and also within the range of an antibiotic

Back 60

remember that

Front 61

ways a cell can affect bacterial growth

Back 61

inhibition of cell wall synthesis
inhibit protein synthesis
inhibit nucleic acid synthesis
competitive inhibition of enzymatic activity

Front 62

what antibiotics inhibit peptidoglycan synthesis

Back 62

penicillin
ampicillin
cepatholothin
vancomycin

Front 63

what antibiotics inhibit bacterial protein syntehsis

Back 63

tetracycline
erythromycin

Front 64

if a particular bacterial strain is sensitive to an antibiotic what will happen

Back 64

a circular zone/clearing and inhibition is observed surrounding the disk.

Front 65

what will ultimately determine the resistance of a bacterial strain to an antibiotic

Back 65

depends on the SIZE of the zone of inhibition.

Front 66

what region of the electromagnetic spectrum does UV light occupy?

Back 66

100-400 nm

Front 67

UV light and its effect on cells

Back 67

damages cells because DNA absorbs light of this wavelength.

Front 68

what can happen to DNA when exposed to UV light

Back 68

a mutation known as thymine dimer.

Front 69

what are thymine dimers

Back 69

formed when UV leads to a covalent linkage between adjacent thymine residues on the same DNA strand.

leads to a distortion in the shape of the double helix and results in errors during replication.

Front 70

T/F UV light penetrates the surface for deep damage

Back 70

False, UV light is not very penetration and so its effects are limited to the surface this exposed to the radiatin.

Front 71

what are the variables that influence the effectiveness of UV light as a germicide

Back 71

1. the type of wavelength (shorter about 260 nm are > that longer)
2. duration of exposure (longer > shorter)
3. type of organism (endospores are more resistant than vegetative)
4. Activation of the cellular DNA repair machinery (if the DNA repair system is overwhelmed, many mutations can accumulate)

Front 72

ultraviolet is between what two numbers on the electromagnetic spectrum

Back 72

100 -400 nm

Front 73

visible light on the electromagnetic spectrum

Back 73

400-750nm

Front 74

infrared on the electromagnetic spectrum

Back 74

450-1000nm