Microbial metabolism

Question 1

Lag phase?

Answer 1

1. Initial period of adaptation to a new environment2. Increase in metabolic activity3. Sensitive to antimicrobials4. Little to no cell division

Question 2

During what stage(s) are bacteria susceptible to antimicrobials?

Answer 2

1. Lag2. Exponential

Question 3

Exponential phase

Answer 3

1. Rapid multiplication by binary fission2. Most susceptible to antibiotics

Question 4

Stationary phase

Answer 4

1. Nutrients depleted, waste products accumulate2. Decreased growth rate3. Spore forming bacteria initiate sporulation

Question 5

During what growth phase do spore forming bacteria begin sporulation?

Answer 5

Stationary phase

Question 6

Decline phase

Answer 6

More bacteria die than are generated

Question 7

Obligate aerobe

Answer 7

Bacteria that require oxygen and metabolize by respiration

Question 8

Obligate anaerobe

Answer 8

Bacteria that are inhibited or killed by oxygen and utilize fermentation exclusively for energy production

Question 9

Facultative anaerobe

Answer 9

1. Bacteria that grow well under aerobic or anaerobic conditions. If oxygen is available they respire, if not they use fermentation2. Majority of bacteria

Question 10

Microaerophilic

Answer 10

Require 5-10% oxygen for optimal growth

Question 11

What does catalase (or peroxidase) do?

Answer 11

Breaks down H2O2 into O2 and H2O

Question 12

What does superoxide dismutase do?

Answer 12

Detoxifies O2- to H2O and O2

Question 13

What must bacteria synthesize to make nucleic acids, making it a target for antibiotics?

Answer 13

Folate

Question 14

What do quinolones target?

Answer 14

DNA gyrase

Question 15

What drug class targets DNA gyrase?

Answer 15

Quinolones

Question 16

What does rifampin target?

Answer 16

Bacterial DNA-dependent RNA polymerase

Question 17

What is the precursor subunit of peptidoglycan?

Answer 17

UDP-N-acetyl muramic acid

Question 18

Where is UDP-N-acetyl muramic acid synthesized?

Answer 18

Bacterial cytoplasm

Question 19

What is added to the 3rd carbon of UDP-N-acetyl glucosamine to make UDP-N-acetyl muramic acid?

Answer 19

Lactyl group

Question 20

What occurs once UDP-NAM is made?

Answer 20

5 amino acids are added to it

Question 21

What happens to the UDP-NAM-pentapeptide after it is formed?

Answer 21

Transferred from UDP to bactoprenol phosphate at membrane surface

Question 22

What happens to bactoprenol-NAM-pentapeptide to form the final disaccharide-pentapeptide precursor product?

Answer 22

NAG is transferred from UDP-NAG to it

Question 23

How are the peptide side chains linked together?

Answer 23

Transpeptidation

Question 24

What is transpeptidation?

Answer 24

1. Cross linking of peptide chains by peptide bond exchange2. Occurs on outer leaflet of plasma membrane

Question 25

Where does transpeptidation occur?

Answer 25

Outer leaflet of plasma membrane