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

Importance of the surface of a bacterium?

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

Cell wall composition?

Answer 10

Peptide linked chains of amino sugars
Parallel polymers of disaccharides (glycan chains) which are cross-linked with peptides of four AAs

Question 11

Starting molecule for bacterial cell wall building?

Answer 11

N-acetyl glucosamine

Question 12

What does N-acetyl glucosamine get converted into?

Answer 12

N-acetyl muramic acid

Question 13

What is done to the N-acetyl muramic acid?

Answer 13

5 AAs are added onto it

Question 14

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

Answer 14

Parks nucleotide

Question 15

What happens to parks nucleotide?

Answer 15

It is attached to they cytoplasmic membrane using undecaprenyl propanoate

Question 16

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

Answer 16

Lipid 1

Question 17

What is added to lipid 1?

Answer 17

N-acetyl glucosamine

Question 18

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

Answer 18

Lipid 2

Question 19

What is used to move lipid 2 to the periplasm?

Answer 19

FLipases enzymes

Question 20

What is the periplasm?

Answer 20

Area between the cytoplasmic membrane and the cell wall

Question 21

What is transglycosylation?

Answer 21

Linking two sugars together in cell wall formation

Question 22

What is transpeptidation?

Answer 22

Generation of AA cross links in the cell wall synthesis

Question 23

What gives the cell wall its stability?

Answer 23

Linking AA

Question 24

What is done as part of transpeptidation?

Answer 24

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

Question 25

4 main stages of bacterial cell wall synthesis?

Answer 25

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

Question 26

How does vancomycin work?

Answer 26

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

Question 27

How does penicillin work?

Answer 27

Binds to transpeptidase enzyme and blocks cross bridge formation

Question 28

How is the cell wall grown?

Answer 28

ENzymes cut the crosslinks and allow new peptidoglycan to be incorporated