Bacterial Structure, Function, and Growth

Question 1

Why is the peptidoglycan layer such a great target for antimicrobial drugs?

Answer 1

Because it is unique to bacteria and (usually) required.

Question 2

What eukaryotic protein attacks the peptidoglycan layer?

Answer 2

Lysozyme, by hydrolyzing the bond between N-acetylglucosamine and N-acetylmuramic acid

Question 3

The building blocks of peptidoglycan are _________.

Answer 3

N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNac)

Question 4

Lipopolysaccharide is the _________.

Answer 4

main lipid of the outer leaflet of the outer membrane

Question 5

Lipopolysaccharide is also called ________.

Answer 5

endotoxin

Question 6

Other than endotoxin, the outer membrane of gram-negative bacteria contains _______.

Answer 6

porins and lipoprotein

Question 7

What does lipoprotein do?

Answer 7

It anchors the outer membrane to the peptidoglycan of the inter-membrane space

Question 8

Describe the composition of LPS.

Answer 8

It connects to the outer membrane via three phospholipids (a disaccharide phospholipid called lipid A), which then connects to a core polysaccharide and finally (most distally) a repeating oligosaccharide unit called O antigen

Question 9

What is the toxic component of LPS?

Answer 9

Lipid A (the disaccharide phospholipid)

Question 10

What two vaccines (mentioned in class) are anti-capsular antibodies?

Answer 10

Pneumococcus and hemophilus influenzae type B

Question 11

Bacteria secrete a slime called ________ that allows them to stick to ________.

Answer 11

glycocalyx; host cells, the world, and/or each other

Question 12

Biofilm (glycocalyx) protects bacteria from _______.

Answer 12

phagocytosis, complement, and antimicrobial agents

Question 13

List the functions of bacterial secretion systems.

Answer 13

(1) deliver proteins to the cell surface; (2) assemble organelles on the cell surface; (3) export proteins to the extracellular environment; and (4) inject proteins or DNA into other cells.

Question 14

Describe the structure of secretion-system proteins.

Answer 14

They have inner-membrane rings, outer-membrane rings, and needles.

Question 15

List the eukaryotic proteins that are analogous to MreB, CreS, and FtsZ.

Answer 15

FtsZ - tubulin; MreB - actin; CreS - intermediate filaments

Question 16

Although both Gram-positive and Gram-negative bacteria have peptidoglycan, Gram-positive bacteria ___________.

Answer 16

have more, and the peptidoglycan is more extensively cross-linked

Question 17

Teichoic acids are found on _________ bacteria and function to help __________.

Answer 17

Gram-positive; stabilize the outer membrane

Question 18

Lipoteichoic acids connect to the _________.

Answer 18

lipid membrane

Question 19

Capsules are composed of _________.

Answer 19

complex polysaccharides

Question 20

____________ flagellar movement results in movement.

Answer 20

Counterclockwise

Question 21

The cytoplasmic membranes (inner) of bacteria contains no _______, unlike animal cells.

Answer 21

sterols

Question 22

Bacterial membranes are impermeable to ______ molecules.

Answer 22

charged

Question 23

Heterotrophic bacteria require ________, while autotrophic bacteria require _______.

Answer 23

organic carbon; CO2

Question 24

List the categories of O2 requirement.

Answer 24

Strict aerobe (requires O2, will die without); strict anerobe (does not require O2, will die with O2); indifferent anerobe (does not need O2, but can survive in the presence of O2); facultative anerobe (usually needs O2, but can survive without)

Question 25

The beta-lactams (penicillin, cephalosporin), vancomycin, and cycloserine all inhibit ________.

Answer 25

formation of the peptidoglycan layer

Question 26

Endospores are produced by some _________ bacteria.

Answer 26

Gram-positive