Chapter 2/4: Bacterial Cell Walls

Question 1

What are most bacterial cell walls composed of?

Answer 1

Peptidoglycan

Question 2

Which two alternating molecules make up petidoglycan?

Answer 2

NAM, NAG

Question 3

Which peptidoglycan subunit is cross-linked at adjacent layers by peptide bonds?

Answer 3

NAM

Question 4

Which two amino acids are connected by a single peptide bond in peptidoglycan cross-linking?

Answer 4

DAP, D-Ala

Question 5

Which two amino acids are connected by a pentaglycine interbridge in peptidoglycan-cross linking?

Answer 5

L-Lys, D-Ala

Question 6

What type of bacteria use a single peptide bond in peptidoglycan cross-linking?

Answer 6

Gram negative

Question 7

What type of bacteria use a pentaglycine interbridge in peptidoglycan cross-linking?

Answer 7

Gram positive

Question 8

What molecule acts as a carrier for NAM in peptidoglycan synthesis?

Answer 8

UDP

Question 9

What serves as a transport channel across the plasma membrane in peptidoglycan synthesis?

Answer 9

Bactoprenol

Question 10

What is the name for the space between the plasma membrane and cell wall?

Answer 10

Periplasm

Question 11

What protein can cleave the bond between NAM-NAG subunits in the peptidoglycan backbone?

Answer 11

Lysozyme

Question 12

What type of structure forms in Gram positive cells after lysozyme treatment?

Answer 12

Protoplast

Question 13

What type of structure forms in Gram negative cells after lysozyme treatment?

Answer 13

Spheroplast

Question 14

What molecule can cleave the peptide interbridge cross-link in certain Staphylococcus species?

Answer 14

Lysostaphin

Question 15

What type of antibiotics prevent transpeptidation?

Answer 15

Beta-lactam

Question 16

What is produced in resistance to Beta-lactam antibiotics?

Answer 16

Beta-lactamases

Question 17

What drug binds to Bactoprenol to prevent subunit synthesis and transport?

Answer 17

Bacitracin

Question 18

What drug prevents NAM-NAG linkages from forming and transpeptidation?

Answer 18

Vancomycin

Question 19

What are three types of Beta-lactam antibiotics?

Answer 19

Penicillin, Ampicillin, Cephalosporin

Question 20

What types of major phenetic group divisions are based on cell wall chemistry differences?

Answer 20

Gram positive vs. Gram negative, Acid fast vs. non acid-fast

Question 21

What type of bacteria lack a cell wall completely?

Answer 21

Mycoplasma sp.

Question 22

What color are Gram-negative cells stained?

Answer 22

Pink

Question 23

What color are Gram-positive cells stained?

Answer 23

Purple

Question 24

What type of cell walls have a thick outer layer of peptidoglycan and a very narrow periplasmic space?

Answer 24

Gram-positive cell walls

Question 25

What negatively charged molecules spear through the peptidoglycan layers in Gram-positive cell walls?

Answer 25

Teichoic acids

Question 26

What function do Teichoic acids serve in Gram-positive cell walls?

Answer 26

Structure

Question 27

What type of cell walls have a varying width periplasmic space and a thin layer of peptidoglycan?

Answer 27

Gram-negative cell walls

Question 28

What type of cell walls have an additional outer membrane?

Answer 28

Gram-negative cell walls

Question 29

What is the outer membrane composed of in Gram-negative cell walls?

Answer 29

Lipopolysaccharide (LPS)

Question 30

What type of cell walls have a peptidoglycan layer with large pores?

Answer 30

Gram-positive cell walls

Question 31

What proteins serve in transport in Gram-negative cells?

Answer 31

Porin, TonB

Question 32

What type of rare transporters allow movement from the periplasm directly to the outside of the cell?

Answer 32

Autotransporters

Question 33

What type of transporters shuttle materials from the cytoplasm to outside of cell in a single step?

Answer 33

Type III

Question 34

What primary stain is used in a gram stain?

Answer 34

Crystal violet

Question 35

What mordant is used in a gram stain to crystallize purple stain?

Answer 35

Gram's iodine

Question 36

What decolorizer dissolves lipopolysaccharides and shrinks Gram-positive large pores in a gram stain?

Answer 36

95% ethanol

Question 37

What counterstain enters only vacant cells in a gram stain?

Answer 37

Safranin