export_microbial metabolism

Question 1

Importance of metabolic differences in bacteria

Answer 1

Can distinguish between prokaryotes and eukaryotes for development of antibacterial therapies

Question 2

Binary fission

Answer 2

An exact copy of the genome is made and a single cell divides into two daughter cells

Question 3

Typical growth curve

Answer 3

Lag phase
Exponential phase

Stationary phase

Decline

Question 4

Lag phase

Answer 4

Building up metabolites, but no division

Question 5

Exponential phase

Answer 5

Actively dividing

2 -> 4 -> 8 -> 16

Question 6

Stationary phase

Answer 6

Out of materials for divisions, spores are being formed in this stage (Gram positive ONLY)

Question 7

Decline

Answer 7

The bacteria begin to die

Question 8

Bacterial biosynthesis

Answer 8

Nucleic acids and proteins

Peptidoglycans

Question 9

Factors that affect bacterial growth in culture

Answer 9

pH optimum
Aerobic vs. anaerobic

Nutrients/composition of media

Temperature

Question 10

Groups based on metabolic properties

Answer 10

How it deals with oxygen

Energy source of the organism

Question 11

Aerobe

Answer 11

Exclusively utilizes respiration to meet energy needs

Question 12

Anaerobe

Answer 12

Exclusively uses fermentation to meet energy needs

Oxygen kills this bacteria

Question 13

Facultative anaerobes

Answer 13

Can respire or ferment

Question 14

Microaerophilic

Answer 14

Grows best at low O2, but can grow without O2 as well

Question 15

Aerobic bacteria against ROS

Answer 15

Catalase (H2O2)

SOD (detox O2-)

Question 16

Bacterial energy production efficiency

Answer 16

Aerobic (most efficient)
Anaerobic

Ferment (least efficient)

Question 17

Aerobic respiration

Answer 17

O2 is the terminal electron acceptor

Question 18

Anaerobic respiration

Answer 18

Inorganic molecules are terminal electron acceptors

Question 19

Fermentation

Answer 19

Fermentable substrate is final electron acceptor

Question 20

Fermentation process

Answer 20

Pyruvate is converted to various end products

Bacteria can be identified by these products

Question 21

Antibiotic targeting based on bacterial metabolism

Answer 21

Cell wall synthesis
DNA replication

RNA synthesis

Antimetabolites

Protein synthesis

Question 22

Nucleic acid synthesis targeting

Answer 22

These are needed for DNA and RNA, as well as ATP and GTP
Needed for NAD, FAD, CoA, UDP-glucose, and cAMP/cGMP

Folate needed for purines and thymidines

Question 23

Folate targeting in bacteria

Answer 23

Folate derived from PABA

Inhibiting folate synthesis is selective to bacteria since we get folic acid from our diet

Question 24

DNA replication targeting

Answer 24

Bacterial DNA gyrase needed for unwinding/winding DNA - target of quinolones

Question 25

Structure of peptidoglycan

Answer 25

Meshlike layer Pentaglycine bridges sometimes used to aid in cross-linking (Gram positive only) Peptide cross-linking occurs between terminal D-Ala from one chain to Lys (or other diamino a.a.) from other chain

Question 26

Step one of peptidoglycan synthesis

Answer 26

Carbohydrate subunits activated (NAG and NAM) with UDP in the cytoplasm

Question 27

Step two of peptidoglycan synthesis

Answer 27

A pentapeptide is added to NAM-UDP | L-Ala (varies) - D-Glu (varies) - L-Lys (diamino a.a.) - D-Ala - D-Ala

Question 28

Step three of peptidoglycan synthesis

Answer 28

UDP-NAM-pentapetide attached to bactoprenol through pyrophosphate link, UMP released

Question 29

Step four of peptidoglycan synthesis

Answer 29

NAG added to NAM-pentapeptide-bactoprenol complex

Question 30

Step five of peptidoglycan synthesis

Answer 30

Bactoprenol (carrier protein) transport NAG-NAM pentapeptide repeat until across membrane

Question 31

Step six of peptidoglycan synthesis

Answer 31

Disaccharide unit attached to end of growing peptidoglycan chain by transglycosylases

Question 32

Step seven of peptidoglycan synthesis

Answer 32

Pyrophosphobactoprenol is converted back to phosphobactoprenol and recycled

Question 33

Transpeptidation

Answer 33

Occurs between free amine of diamino amino acid (third a.a. in chain) and D-Ala in the fourth position of another peptide chain, releasing D-Ala precursor Occurs on outer leaflet

Question 34

Penicillin Binding Proteins (PBP)

Answer 34

Transpeptidases | Targets for penicillins and other beta-lactam antibiotics