Microbiology Exam 2 Study Guide

Front 1

Name several ways (5) phagocytes may fail to remove/eliminate the infectious agents

Back 1

1. Inhibits opsonization/chemostaxis -> kills phagocytic cells
2. Inhibits phagocytosis; prevents uptake of these cells
3. Once inside, prevents lysosomal fussions
4. Escape lysosome & grow in cytoplasm
5. Resist antibacterial lysosomal action & multiply within cell -> block activation by interferon-gamma

Front 2

Name several exotoxins (4) and discuss their mode of action

Back 2

1. C. diphtheria -> disrupts protein synthesis, causing cell death
2. C. tetani -> blocks inhibitory NT release; continuous excitatory NT stimulation
3. C. botulinum -> prevents release of excitatory NT so stimulation of muscle is blocked
4. V. cholerae -> increases cAMP; causes inhibition of absorption of elements (water & ions), producing watery stool

Front 3

Koch’s postulates: its uses (4)

Back 3

1) Observation
2) Isolation in Pure Culture to separate microbe
3) Re-Infection in healthy people
4) Re-Observation to see is disease is present in newly infected people. Re-isolation in pure culture.

Front 4

Koch’s postulates: its exceptions
NOT used for (3)

Back 4

-Mycobacterium leprae (leprosy) b/c of slow growth so cannot be isolated.
-Treponemma Paillidum(syphilis) b/c needs human tissue to grow.
- Polymicrobic infections, causing same disease.

Front 5

What are the significance of LD50 and ID50?

Back 5

LD50 stands for LETHAL DOSE. It means how many microbes kill ½ people that get it.
ID50 stands for INFECTIOUS DOSE. How many microbes bring down ½ people that come in contact with it.
The lower the number, means the more virulent it is. More virulent means more efficient organism is.

Front 6

T/F
The lower the LD50 and ID50 the more virulent the organism is.

Back 6

True

Front 7

Differentiate between, pili, fimbrae, cilia, lipoteichoic acid and adhesions.

Back 7

- Pili - short appendages used to transfer DNA from one cell to another; highly specific, promotes adhesion & blood clotting, prevents phagocytosis
- Fimbrae – short appendages used to adhere to surfaces
- Cilia remove microorganisms by propelling motion
- Lipoteichoic acid – in gram positive only
- Adhesions – general binding to target; can be pili, fimbrae, lipoteichoic acid, glycocalyx, and adherence proteins

Front 8

The function of "mucociliary elevators" is to:
A. Remove microorganisms from the lower respiratory tract
B. Remove microorganisms from the gastrointestinal tract
C. Kill microorganisms
D. Remove microorganisms from internal cavities

Back 8

The function of "mucociliary elevators" is to:
A. Remove microorganisms from the lower respiratory tract

Front 9

Discuss the formation and significance of biofilm and colonization. Also note on quorum sensing.

Back 9

Biofilm allows organisms to stick together which promotes colonization in other parts of body. Like a cell adhesion.
Quorum Sensing is when a lot of bacteria attach and encourage other bacteria to join which promotes growth.

Front 10

Compare and contrast: endotoxin, exotoxins, enterotoxins, neurotoxins, and cytotoxins

Back 10

Endotoxin-is a structural component of bacteria that is released when they die; part of Gram negative structure Ex: LPS
Exotoxin - excreted by a microorganism; dimeric molecules, made of 2 components (one allows attachment, other is functional);
Enterotoxin- requires entry of cell. Is a toxin released in the Intestines. They are frequently cytotoxic…B needed for entry into cell; A needed for toxin activity
Neurotoxin-affects normal nerve cell function
Cytolytic toxins- attack surfaces

Front 11

Exotoxins are...(3)

Back 11

-highly toxic
-nonpyrogenic
-highly immunogenic

Front 12

Endotoxins are...(3)

Back 12

-weakly toxic
-pyrogenic
-weakly immunogenic

Front 13

What is a superantigen?

Back 13

Produced by some bacteria, they Overactivate Tcells by non-specific binding so results in excess of cytokines which leads to damage.

Front 14

Which of the following is true of endotoxins
1. They are integral parts of Gram-negative outer membrane
2. They are heat resistant
3. They may stimulate macrophages to secret cytokine
4. All are correct

Back 14

Which of the following is true of endotoxins
4. All are correct

Front 15

Exotoxins:
1. Are usually made of protein.
2. Always kill the host cell
3. Are made only by gram-positive bacteria
4. Are always enzymes
5. None of the options are correct

Back 15

Exotoxins:
1. Are usually made of protein.

Front 16

Which of the following could be administered as vaccine?
1. Toxoid
2. Antitoxin
3. Enterotoxin
4. Exotoxins

Back 16

Which of the following could be administered as vaccine?
1. Toxoid

Front 17

Diphtheria toxin is an exotoxin produced by Corynebacterium diphtheriae.
It enters the cells and:
1. Causes the cells to lose their ability to make protein
2. Interferes with nerve-muscle communication
3. Interferes with cell division and binary fission
4. Causes cells to lose electrolytes into environment of intestine

Back 17

Diphtheria toxin is an exotoxin produced by Corynebacterium diphtheriae.
It enters the cells and:
1. Causes the cells to lose their ability to make protein

Front 18

The paralysis in tetanus is due to a neurotoxin that
1. inhibits the release of a neurotransmitter needed to relax muscles and cause rigid paralysis
2. Acts in the brain to cause excess muscle contraction.
3. Interferes with synaptic transmission and causes placid paralysis
4. Acts exclusively on the respiratory musculature.
5. Inhibits protein synthesis in heart muscle.

Back 18

The paralysis in tetanus is due to a neurotoxin that
1. inhibits the release of a neurotransmitter needed to relax muscles and cause rigid paralysis

Front 19

Which of the following is an enterotoxin
1. Botulin toxin
2. Tetanus toxin
3. Cholera toxin
4. Lipopolysaccharide
5. Diphtheria toxin

Back 19

Which of the following is an enterotoxin
3. Cholera toxin

Front 20

Some antigens are considered "super antigens" because they:
1. They are active in low concentrations because they are neurotoxins
2. Over stimulate the host immune system in a non-specific manner
3. They can invade and kill many different eucaryotic cell types
4. They inhibit protein synthesis in susceptible cells, causing cell death.
5. They inhibit DNA synthesis in susceptible cells, causing cell death.

Back 20

Some antigens are considered "super antigens" because they:
2. Over stimulate the host immune system in a non-specific manner

Front 21

Disseminated intravascular coagulation (DIC) or shock may result from
exposure to:
1. Cytolytic toxins
2. Neurotoxins
3. Leukocidins
4. Endotoxin

Back 21

Disseminated intravascular coagulation (DIC) or shock may result from
exposure to:
4. Endotoxin

Front 22

The major function of bacterial capsules in virulence is to:
1. Inhibit phagocytosis
2. Act as a permeability barrier to toxic factors and antibiotics
3. Retain the rigidity of the cell
4. Serve as an adhesin
5. Protect the spore

Back 22

The major function of bacterial capsules in virulence is to:
1. Inhibit phagocytosis

Front 23

What is the significance of normal flora?

Back 23

They are organisms associated with healthy body tissues.
Skin has Staphylococcus Corynebacterium.
Teeth has Streptococcus mutans.
Small Intestine has Lactobacilli. Upper Resp. Tract has Staph, Strep.
Urethra has E.coli & Proteus Vagina has Lactobacilli.

Front 24

Many virulence factors are enzymes that degrade or otherwise harm host
tissue. Which of the following destroys white blood cell?
1. Hyaluronidase
2. Hemolysins
3. Leukocidines
4. Streptokinases
5. Collagenase

Back 24

Many virulence factors are enzymes that degrade or otherwise harm host
tissue. Which of the following destroys white blood cell?
3. Leukocidines

Front 25

The normal flora:
1. Never causes disease, by definition
2. Has no biological function other than to make culture of pathogens more difficult.
3. Is restricted to the gastrointestinal and urogenital tracts
4. Consists of bacteria found frequently on or in healthy people
5. All options are correct

Back 25

The normal flora:
4. Consists of bacteria found frequently on or in healthy people

Front 26

Name ways bacteria may evade immune system (8)

Back 26

1) Fast in/out
2) Remaining inside a host cell
3) Infecting “privileged sites” like nerve sites
4) Mimicking host antigens
5) Binding host Ab “upside down” (Fc portion so it would be unusable)
6) Antigenic variation-confuses humoral response
7) Actively suppressing immune system
8) Capsules prevent phagocytosis

Front 27

What are the prevalent infectious diseases in the US? 3

Back 27

-Upper respiratory disease
-Gastroenteritis
-STD

Front 28

What are the prevalent infectious diseases in developing countries?

Back 28

-Intestinal- rotaviruses, salmonella, camphylobacter
-Respiratory diseases
-AIDS
-Diseases caused by lack of immunization - tetanus

Front 29

Name the three incidents over the last century that brought infectious diseases under control. List the disease controlled by each incidence.

Back 29

Chlorine to treat the water.-reduced cholera and typhoid fever.
First use of Penicillin.-pneumonia
Passage of Vaccination Assistance Act.- smallpox eradicated.

Front 30

Nosocomial infections; definition, causative agents, contributing factors

Back 30

Nosocomial-associated with a stay in the hospital b/c of weakened immune system contributes.
Can be caused by breakdown of barriers. (Burns, catheters,surgery,endoscopy,chemo.)
Antibiotic resistant bacteria is known to live in hospitals.
1/20 patients infected. 1/400 deaths. Very High #.
Crowding increases risk.

Front 31

Pathogen is...

Back 31

bacteria capable of causing a disease.

Front 32

Disease is...

Back 32

abnormal condition or function

Front 33

Infection is...

Back 33

Infection-Is the growth of a microbe within a host. May be asymptomatic or cause disease.

Front 34

Virulence is...

Back 34

Virulence-relative ability to cause disease. The more virulent means more harm it can do.

Front 35

Opportunistic Pathogen is...

Back 35

Opportunistic Pathogen- a pathogen that USUALLY does not cause disease in a healthy person. If immune-compromised pathogen has chance to infect.

Front 36

Compare and contrast invasive vs. non-invasive infections

Back 36

A non-invasive infection is highly toxic. It doesn’t grow much. Ex: food born toxins, Clostridium Botulinum & Staphylococcus Aureus.
Invasive infection produces little or no toxin. Ex: Shigella strains & TB. This type does damage by spreading.

Front 37

Give examples of and describe the mode of action of enzymes that facilitate invasion by bacteria (7)

Back 37

1. Hyaluronidase allows bact. To spread easier
2. Collagenase dissolves collagen to allow bact to spread easier
3. Streptokinase kills both RBC & WBC; also allow easy bact spreading
4. Coagulase clots around microbes, isolating from rest of body
5. Hemolysins kill RBC
6. Leukocidins kill WBC
7. Streptolysin kills WBC, platelets, RBC.

Front 38

Significance of capsule, its role in pathogenicity, and what happens if a cell loses its capsule?

Back 38

Capsule is considered a virulence factor and is the cause of some disease. It helps protect bacteria against phagocytosis and from dessication. They may also help the organism adhere.

Front 39

What are the routes of entry for infectious diseases, what is meant by parentral route? Vector transmission?

Back 39

Vector transmission is through an insect bite, carries disease from one host to another. Parentral route means the transmissions is through piercing of the skin or mucous membranes.

Front 40

Famous Microbiologists and their achievements
Leeuwenhoek?

Back 40

-first microbiologist

Front 41

Famous Microbiologists and their achievements
Hooke

Back 41

-first to see and define microbes, cells

Front 42

Famous Microbiologists and their achievements
Koch-

Back 42

his postulates on microbes and diseases

Front 43

Famous Microbiologists and their achievements
Jenner-

Back 43

discovered immunization, smallpox

Front 44

Famous Microbiologists and their achievements
Fleming

Back 44

Fleming-penicillin

Front 45

Famous Microbiologists and their achievements
Ehrlich

Back 45

Ehrlich-magic bullet, salvarsan-syphilis

Front 46

Famous Microbiologists and their achievements
Pasteur

Back 46

Pasteur - fermentation, pastereurization, “father”

Front 47

Famous Microbiologists and their achievements
Senelweiss

Back 47

Senelweiss-aseptic technique

Front 48

Know the kingdoms in the five-kingdom system. Where viruses stand in this system

Back 48

5 kingdoms: fungi, plants, animals, protozoans, monera
Viruses are not in kingdoms or domains, not officially a microbe.

Front 49

Relative sizes of microorganisms

Back 49

0.5-2.0 microns (RBC is 7.5 mi) Eukaryote of 20mi=BIG

Front 50

What was the magic bullet?

Back 50

Effectively targeting a bacteria without affecting other organism. Associated with Ehrlich and his syphilis research.

Front 51

What are the major bioelements (6)

Back 51

C, O,N, H, S, P

Front 52

Components of cell wall and cell membrane in both Gram + and - cells.

Back 52

Gram(+)Techoic Acid. Has thicker cell wall.
Gram(-)LPS, an endotoxin that is released when bacteria dies. Porin Proteins that make it more resistant to entry. Thinner cell wall.

Front 53

What is an amphipathic molecule?

Back 53

A molecule containing both hydrophobic (FA) and hydrophilic (glycerol) group.

Front 54

What are examples of monomers/polymers you may find in the cell. (4)

Back 54

1. Sugars/polysaccharides
2. FA/lipids
3. Nucleotide bases/nucleic acids
4. AA/proteins

Front 55

Loss of electron means ______

Back 55

oxidation

Front 56

Gain of electron means ______

Back 56

reduction

Front 57

Know shapes of the bacteria.

Back 57

Cocci (round) Bacilli( rods) Spirillum (curved rods) Spirochete (squiggly line

Front 58

What Peptidoglycan is made of?

Back 58

Large polymer of N-acetyl glucosamine and N-acetyl muramic acid. It is the main structural component of bacteria cell walls. It is found only in prokaryotes. And is more prevalent in Gram+ bacteria.

Front 59

What is considered an endotoxin?

Back 59

Substance in bacteria that is released when they die. LPS is the example from Gram (-) bacteria.