Micro Lecture 2

Question 1

What are plasmids?

Answer 1

Self-replicating circular pieces of DNA, 1-5% the size of bact. chromosome

Question 2

What are transposons?

Answer 2

Segments of DNA that can move from one region of DNA to another

Question 3

What are insertion sequences?

Answer 3

Sequences in transposons that cut and reseal DNA

Question 4

Fermentation test

Answer 4

Bacteria that catabolize carb or protein produce acid, pH indicator turns yellow

Question 5

Oxidase test

Answer 5

Tests for bacteria that have cytochrome oxidase (produces gas bubbles)

Question 6

Define antigenic

Answer 6

Stimulates body to form antibodies

Question 7

Slide agglutination test

Answer 7

Bacteria agglutinate when mixed with antiserum containing antibodies produced in response to that strain

Question 8

Phage typing

Answer 8

Plaques (clearings) appear where phages infect and lyse bacterial cells

Question 9

DNA chip (microarray)

Answer 9

Contains DNA probes, detects pathogens by hybridization

Question 10

Selective toxicity

Answer 10

Destroying pathogens without destroying host

Question 11

Bacteriocidal

Answer 11

Kills microbes directly

Question 12

Bacteriostatic

Answer 12

Prevents microbes from growing

Question 13

Penicillin

Answer 13

beta-lactam ring, prevents cross-linking of peptidoglycans, interferes with primarily gram-positive

Question 14

Aminoglycosides

Answer 14

Change shape of ribosome, ex. streptomycin

Question 15

Tetracyclines

Answer 15

Broad spectrum, interfere with tRNA attachment to ribosome

Question 16

Polymyxin B

Answer 16

Effective against gram-negatives

Question 17

Antimetabolites

Answer 17

Compete with normal substrates for an enzyme (stops protein synthesis)

Question 18

Rifamycin, Quinolone

Answer 18

Inhibits mRNA synthesis/DNA gyrase

Question 19

Kirby-Bauer (disk-diffusion) test

Answer 19

Tests effectiveness, zone of inhibition determines sensitivity of org. to antibiotic

Question 20

Antibiograms

Answer 20

Reports that record susceptibility of organisms encountered clinically

Question 21

How are resistance genes spread among bacteria?

Answer 21

Horizontally on plasmids, or transposons via conjugation and transduction