Introduction to Microbiology (bailey)

Question 1

What is direct infection?

Answer 1

Comes from toxin of bacteria

Question 2

What is indirect infection

Answer 2

body’s immune response causes disease

Question 3

6 steps of infection

Answer 3

1. Encounter
2. Entry
3. Colonization/Invasion
4. Multiply/Spread
5. Damage
6. Outcome

Question 4

What are the two types of entry?

Answer 4

Ingression: microbes in body cavities that are contiguous
Penetration: microorganisms cross epithelial linings and into deeper tissues

Question 5

What are some characteristics of specific adherence

Answer 5

1. Irreversible
2. Anchoring
3. Adhesins, often found on fimbrae but can be in capsule or cell surface
4. interactions are specific

Question 6

What does hyaluronidase do to facilitate invasion?

Answer 6

destroys extracellular matrix

Question 7

How does coagulate and streptokinase facilitate invasion?

Answer 7

forms clots in which microbes exist and are protected since they are surrounded by body’s own platelets. Pathogens produce streptokinase to dissolve clots and release bacteria

Question 8

What are the 3 methods bacteria use to take up nutrients?

Answer 8

carrier mediated diffusion - facilitated
phosphorylation linked transport - group translocation
active transport - energy dependent

Question 9

What are the two mechanisms of multiplying and spreading?

Answer 9

lateral propogation - multiply then spread

dissemination to distant sites - spread then multiply

Question 10

What are possible outcomes of infection?

Answer 10

1. No disease (below threshold)
2. disease
3. recurrent disease
4. asymptomatic infection
5. death

Question 11

What are 4 factors that define whether a microbe has become a pathogen?

Answer 11

1. it can adhere to host
2. it colonizes the host
3. it replicated within the hidden niche
4. it causes damage via invasion, toxin, activation of immune system

Question 12

What is the main difference in the structure of murein linkages in Gram - vs Gram +

Answer 12

Gram + : thick layer on outside of cell and meurin cross links L-lys to D-ala
Gram - : thin layer between 2 membranes and meurin cross link DAP to D - ala

Question 13

What are the 3 components of LPS of Gram - bacteria?

Answer 13

1. Lipid A
2. Polysaccharide core
3. O-antigen (highly variable)

Question 14

What are PAMPs

Answer 14

pathogen associated molecular patterns, recognized by cells of immune system using pattern recognition receptors

Question 15

Which toll-like receptor (TLR) recognizes LPS?

Answer 15

TLR 4

Question 16

If flagella move counterclockwise, the result is movement or rotation?

Answer 16

movement

rotation/tumbling, if clockwise

Question 17

What is the difference between capsule and slime layer?

Answer 17

capsule - glycocalyx is well organized and firmly attached

slime layer - glycocalyx is unorganized and not firmly attached

Question 18

What do the serological destinations identify?

Answer 18

H: means it is gram negative
O: has a flagella
K: it is capsulated