Bacterial Cell Walls and Envelopes

Question 1

Where is the electron transport chain in bacteria?

Answer 1

on the inside of the cytoplasmic membrane

Question 2

When talking about gram + and gram - with regards to cell walls and envelopes…

Answer 2

gram + = cell wall
gram - = envelope

cell wall= peptidoglycan
envelope= double membrane

Question 3

Where are lipopolysaccharides and teichoic acids found?

Answer 3

lipopolysaccharides = gram -
teichoic acids = only in gram +

Question 4

T/F: There are histones in bacteria

Answer 4

False!
No nucleus/histones in bacteria

Question 5

What is the function of cell wall in bacteria?

Answer 5

to give it a rigid structure and shape

Question 6

Why are bacteria so tough?

Answer 6

peptidoglycan/cell wall layer

Question 7

T/F: bacteria cytoplasmic membrane has a selective permeability barrier

Answer 7

True

Question 8

What is flagella and pili used for?

Answer 8

flagella for motility
pili for attachment/anchor

Question 9

What’s the main difference in gram + vs. gram - ?

Answer 9

• gram + has a THICK peptidoglycan layer on outside of cytoplasmic membrane. stains purple
• gram - has thinner peptidogylcan in the periplasm space between cytoplasmic membrane and outer membrane (more complicated). stains pink

Question 10

Which is more drug sensitive: gram + or gram -?

Answer 10

gram +

gram - is more complex and have a more selective channel giving more drug resistance

Question 11

What is the peptidoglycan structure?

Answer 11

alternating N-acetyl muramic acid with N-acetyl glucosamine connected via amino acid peptides

Question 12

How do B-lactam drugs work?

Answer 12

stop cross linking from happening in peptidoglycan so it falls apart

Question 13

What is found in gram - but not in gram + ?

Answer 13

LPS

Question 14

What is found in gram + but not in gram - ?

Answer 14

teichoic acids

• woven in peptidoglycan

Question 15

What is a polysaccharide capsule?

Answer 15

can be in gram +/- and is the outermost surface as another carbohydrate layer

main importance: adhesion to surfaces and cause biofilms, evade immune system, reduce phagocytosis, and shield protein antigens

Question 16

Where is acid fast staining found and why does it occur?

Answer 16

found in mycobacteria that have gram + walls due to long-chain fatty acid mycelia acid on the exterior

Question 17

What type of bacteria is E.coli?

Answer 17

gram -

Question 18

What is the structure of LPS?

Answer 18

lipid A (immuno reactive lipid) and a long carbohydrate called O- antigen

Question 19

Where are LPS found in gram - bacteria?

Answer 19

outermost layer

Question 20

What are the polysaccharides of the capsule used as?

Answer 20

vaccines specifically in children

Question 21

What does HOK stand for?

Answer 21

H- flagella
O- LPS O-antigen
K- capsule

Question 22

What does HOK stand for?

Answer 22

H- flagella
O- LPS O-antigen
K- capsule

Question 23

How does the capsule stain?

Answer 23

it doesn’t- it shows up clear on stains

Question 24

Which bacteria is more common in flagella for motility and fimbriae/pili for attachment?

Answer 24

flagella= both gram + and -
fimbriae/pili= more commonly gram -

Question 25

How does flagella allow for movement?

Answer 25

they have sensors/receptors on them to detect for specific things/gradients

Question 26

What is treponema denticole?

Answer 26

oral spirochete that is gram - with a unique flagella in periplasmic space

Question 27

What is a major virulence factor of E.coli that allows colonization in the urinary tract epithelium?

Answer 27

fimbriae/pili

Question 28

T/F: Plant cell wall and fungi are the same as bacterial cell walls.

Answer 28

False!
plant/fungi cell walls lack peptidoglycan