The structures of the bacterial cell surface

Question 1

What can we determine from the structure of a bacterium’s cell surface?

Answer 1

How it causes disease, differences between it and closely related species that is harmless, how it survives, what makes it antibiotic resistant

Question 2

What is the surface of a bacterium important for?

Answer 2

Interaction with environment
Gain of nutrition
Protection vs chem and bio threats
attachment

Question 3

Roles of cytoplasmic cell membranes?

Answer 3

Stops cytoplasmic proteins from leaking out
Maintains gradients of ions and nutrients
Protein anchor

Question 4

What is an integral membrane protein?

Answer 4

smthn that runs all the way through the cell membrane

Question 5

Roles of integral membrane proteins?

Question 6

What is an peripheral membrane protein?

Answer 6

Proteins are only on one side of the membrane

Question 7

What can be changed ab the cytoplasmic membrane in response to the environment?

Answer 7

Lipid composition and fluidity of the membrane

Question 8

How are proteins involved in the proton motive force used as antibiotic targets?

Answer 8

If shut down, they can affect motility, dell division, protein secretion and ATP synthesis

Question 9

Role of the cell wall?

Answer 9

Structural supporting layer

Question 10

How are the amino sugars linked in the cell wall

Answer 10

Chains of amino sugars are linked with peptide bonds

Question 11

How is the cell wall structured?

Answer 11

Two parallel polymers of disaccharides (glycan chains) which are cross-linked with peptides of four AAs

Question 12

Starting molecule for bacterial cell wall building?

Answer 12

N-acetyl glucosamine

Question 13

What does N-acetyl glucosamine get converted into?

Answer 13

N-acetyl muramic acid

Question 14

What is done to the N-acetyl muramic acid?

Answer 14

5 AAs are added onto it

Question 15

What is formed as a result of adding 5 AAs onto N-acetyl muramic acid?

Answer 15

Parks nucleotide

Question 16

What happens to parks nucleotide?

Answer 16

It is attached to they cytoplasmic membrane using undecaprenyl propanoate

Question 17

What is formed as a result of attaching parks nucleotide to the cytoplasmic membrane with undecaprenyl propanoate?

Answer 17

Lipid 1

Question 18

What is added to lipid 1?

Answer 18

N-acetyl glucosamine

Question 19

What is formed as a result of adding N-acetyl glucosamine onto lipid 1?

Answer 19

Lipid 2

Question 20

What is used to move lipid 2 to the periplasm?

Answer 20

FLipases enzymes

Question 21

What is the periplasm?

Answer 21

Area between the cytoplasmic membrane and the cell wall

Question 22

What is transglycosylation?

Answer 22

Linking two sugars together in cell wall formation

Question 23

What is transpeptidation?

Answer 23

Generation of AA cross links in the cell wall synthesis

Question 24

What gives the cell wall its stability?

Answer 24

Linking AA

Question 25

What is done to the 5 AA chain as part of transpeptidation?

Answer 25

Remove a d-alanine AA from each AA, and joining the 4th alanine onto the meso-DAP

Question 26

4 main stages of bacterial cell wall synthesis?

Answer 26

1) Building lipid II 2) Lipid II flipping across the membrane 3) transglycosylation 4) transpeptidation

Question 27

How does vancomycin work?

Answer 27

Binds to D-ala-Dala of the 5 AA structure and blocks cross-bridge function

Question 28

How does penicillin work?

Answer 28

Binds to transpeptidase enzyme and blocks cross bridge formation

Question 29

How is the cell wall grown?

Answer 29

ENzymes cut the crosslinks and allow new peptidoglycan to be incorporated