Chapter 1: General Microbiology

Question 1

Cytoplasmic membranes in Gram negative and gram positive bacteria contain what enzymes that helps construct the cell wall or peptidoglycan?

Answer 1

transpeptidases and carboxypeptidases

Question 2

Toxic portion of LPS in Gram negative organisms?

Answer 2

lipid A

Question 3

Understand this image.

Answer 3

NAG NaM
3rd L lysine cross links
4th and 5th Dala
link between NAG and NAM B-1,4

Question 4

Bacitracin effect on PG synthesis.

Answer 4

Interferes with recycling of the pyrophosphobactoprenol back to phosphobactoprenol

Question 5

β-lactam effect on PG synthesis?

Answer 5

targets the PBPs

Question 6

What are resistance mechanisms used by bacteria to resist β lactams?

Answer 6

• decreased binding of antibiotic to the PBP
• decreased concentration of antibiotic at target (gram negative only)
• β-lactamases

Question 7

What organisms have capsules? Use mnemonic to try to remember.

Answer 7

Some Killers Have Pretty Nice Capsules

Streptococcus pneumoniae
Klebsiella pneumoniae
Haemophiluus influenzae
Pseudomonas aeruginosa
Neisseria meningitidis
Cryptococcus neoformans

Question 8

Pili/fimbriae are the primary mechanism of adherence in gram negative or gram positive cells?

Answer 8

gram negative

Question 9

Teichoic acids are the primary mechanisms of adherence in gram negative or gram positive cells?

Answer 9

gram positive

Question 10

What are invasins?

Answer 10

surface proteins that allow an organism to bind to and invade normally non phagocytic human cells; escaping the immune system

Question 11

What are the best examples of organisms that have invasins?

Answer 11

Yersinia psedotuberculosis

Question 12

What are exotoxins?

Answer 12

protein toxins, quite toxic and secreted by bacterial cells

Question 13

Describe endotoxins?

Answer 13

structural toxins (i.e) LPS, Peptidoglycan, teichoic acids

Question 14

Antigenic variation found evidenced in N. gonorrhoeae.

Answer 14

pili and outer membrane proteins

Question 15

Antigenic variation

Answer 15

changing surface ag to avoid immune destruction

Question 16

Antigenic variation example of enterobacteriaceae?

Answer 16

capsular and flagellar ag may or may not be expressed

Question 17

Antigenic variation HIV?

Answer 17

antigenic drift

Question 18

Antigenic variation influenza.

Answer 18

antigenic drift

Question 19

Antigenic variation Trypanosoma brucei rhodesiense?

Answer 19

phase variation

Question 20

Antigenic variation T.b gambiense?

Answer 20

phase variation

Question 21

Antigenic drift?

Answer 21

A subtle change in the surface glycoprotein (either hemagglutinin or neuraminidase) caused by a point mutation or deletion in the viral gene