3-Bacterial Metabolism

Question 1

how to bacteria reprod

Answer 1

~binary fission~
1 cell splits into 2

Question 2

reproduction steps

Answer 2

1. genome replicate
2. cell elongation
3. divison septum forms
4. separation

Question 3

typical growth curve phases

Answer 3

1. lag- no inc in # of cells, fed nutrients to prep for reprod
2. log- exponential inc in cells, uber fast
3. stationary- nutrients are used up, plateau, divisioin=death
4. decline- waste products built up, exponential dec

Question 4

when most sensitive to antimicrobial

Answer 4

lag + log phases

Question 5

less sensitive to antimicrobials

Answer 5

stationary phase

Question 6

cell density determined by?

Answer 6

colony counts on agar plate OR optical density

Question 7

factors that determine growth

culture

Answer 7

1. pH
2. oxygen
3. nutrients of media
4. temp

Question 8

broad classifications

Answer 8

1. how use oxygen
2. how use carbon/energy source

Question 9

aerobe

Answer 9

-exclusively aerobic respir
-oxygen terminal electron receptor

Question 10

facultative anaerobe

Answer 10

-use respiration or fermentation
-grow in presence or absence of oxy

Question 11

anaerobe

Answer 11

-exclusively ferment or anaerobic
-if get oxygen then die (strict)

can be aerotolerant that not use oxy just tolerate

Question 12

microaerophilic

Answer 12

grow best at low oxy (5-10%) but tolerate atomospheric O2 (21%)

Question 13

how bacteria counteract ROS

Answer 13

1. SOD converts superoxide to hydrogen peroxide
2. catalase detoxifies hydrogen peroxide to water and oxy

enzs not present in obligate anaerobes

superoxide dismutase

Question 14

aerobic energy production

Answer 14

most efficient energy generating mode

O2 is terminal electron acceptor

Question 15

anaerobic energy production

Answer 15

inorganic terminal receptors (NO3, SO4)

some facultative orgs and some obligate anaerobes

Question 16

fermentation energy production

Answer 16

organic metabolic intermediates for terminal electron receptors

least efficient

Question 17

fermentation of pyruvate products

Answer 17

acids- if a bacteria uses sugar will result in acid
-can id bacteria based on end products pH

Question 18

where folate comes from

Answer 18

in humans from diet (preformed)
in bacteria from para-aminobenzoic acid

need for syn of purines and thymidine

Question 19

nucleic acid pathway

Answer 19

1. DHDP + PABA (dihydropteroate diphosphate, paraaminobenzoic acid)
2. DHPS enzyme (dihydropteroate synthase)
3. dihydrofolic (DHF) acid
4. DHFR enzyme (dihydrofolate reductase)
5. tetrahydrofolic (THF) acid
6. purines > DNA/RNA or thymidine > DNA

Question 20

sulfonamide blocks what

Answer 20

DHPS enzyme
(dihydropteroate)

Question 21

DHFR inhibitor blocks what

aka trimethoprim

Answer 21

DHFR enzyme
(dihydrofolate reductase)

Question 22

replication steps

Answer 22

1. start at origin of rep
2. two replication forks in oppo directions until terminal site

topoisomerase required to unwind so can target with antibiotics

Question 23

transcription and translation

Answer 23

happen simultaneously in cytoplasm
-ribosomes bind free 5’ end of nascent mRNA (make RNA as transcription happening)

Question 24

ribosomes in translation

Answer 24

70S = 30S (with 16S rRNA) + 50S (with 5S and 23S rRNA)

Question 25

other names for peptidoglycan layer

Answer 25

murein layer
cell wall
sacculus

Question 26

peptidoglycan composistion

Answer 26

alternating NAG-NAM units
-NAG/GlcNAC, NAM/MurNAC

NAM has pentapeptide side chain

Question 27

pentapeptide side chain comp

Answer 27

1. L Ala
2. D-Glu
3. DAP
4. D-Ala
5. D-Ala

Question 28

transglycosylation

Answer 28

lengthening peptido strands by adding units covalently linked NAG-NAM+pentapeptide

enzymes: transglycosylases

Question 29

transpeptidation

Answer 29

peptide bond b/t 3rd position and 4th positon of adj strands
L-Lys or DAP (diamino acid) to D-Ala

by transpeptidases/penicillin binding protein (PBP)

targets for penicillins and B-lactam antibiotics

Question 30

peptidoglycan synthesis

Answer 30

1. NAG and NAM in cytoplasm
2. NAM-pentapeptide made and added to bactoprenol first then NAG added
3. bactoprenol lipid carrier across membrane to inner leaflet
4. attachment to growing end of chain

Question 31

determinant of survival

Answer 31

if cell membrane or not