Driks 3

Question 1

What are 3 ways toxins act?

Answer 1

1. form pore
   - destroy cellular homeostasis
2. go through membrane and do something intracellularly
3. toxin engages receptor on host cell surface and triggers intracellular events

Question 2

What is a type 3 secretory apparatus?

Answer 2

Gram negative bacteria

• tip of needle is able to interact with host cells and partially penetrate the host cell
• serves as conduit for proteins in the bacteria to flow into the host cell—>cause pathogenic events and often allow the bacteria to be taken up

-ex it induces cytoskeletal rearrangement-like in the pedestal

Question 3

What does novobiocin quinolines do?

Answer 3

inhibit gyrase needed for successful completion of DNA replication
-gyrase-detangles knots in DNA synthesis

Question 4

Are transcription and translation coupled in bacteria?

Answer 4

yes

Question 5

What are the steps in peptidoglycan synthesis?

Answer 5

1. subunits of peptidoglycan are synthesized in the cytoplasm
2. subunits are transferred across the membrane by a carrier molecule
3. newly transferred subunits are cross linked to the peptidoglycan already present on the other side on the membrane

Question 6

What are the major targets of antibiotics?

Answer 6

1. RNA polymerase
2. RIbosome inhibitors
3. cell membrane
4. peptidoglycan synthesis

Question 7

What is an example of a siderophores system? How does it work?

Answer 7

Bacteria does the environment with siderophores that bind iron at high affinity and then takes up the siderophore into the cell-takes the iron and spits it back out

-siderophores are essential for virulence-can be encoded on plasmids and shared among bacteria leading to the spread of virulence

Question 8

What happens if a drug impairs the inner membrane of a bacteria?

Answer 8

destroy respiration

-the relevant enzymes are compartmentalized in the inner membrane

Question 9

What do enzymes that detoxify active oxygen created during respiration show?

Answer 9

• useful for diagnosis
• can be virulence factors, since they can detoxify host-generated active oxygen
• give clues for antimicrobial angents

Question 10

What are two generic stress responses?

Answer 10

• spore formation

- synthesis of proteins to protect against heat

Question 11

What are pathogenic stress responses?

Answer 11

• toxins

- pilli

Question 12

Are order and timing of gene expression important in bacteria?

Answer 12

yes

• gene regulation is hierarchical
• gene promoter is activated by a certain environmental stimulus–>activates another tier

Question 13

What is the most fundamental method of analyzing bacteria?

Answer 13

pure culture technique

Question 14

What is the rate of bacterial growth depend on?

Answer 14

1. nature of the culture medium and presence of any appropriate supplemental nutrients
2. the presence or absence of oxygen
3. the temperature

Question 15

What are 3 classes of molecule that must be made prior to cell division?

Answer 15

1. DNA replication
2. Protein synthesis
3. Peptidoglycan

Question 16

What does fermentation tell you?

Answer 16

-the organic molecules produced by fermentation are diagnostic of the infecting organism