quiz 9

Question 1

What is the typical plasmid structure?

Answer 1

circular, double stranded DNA genome residing in a host cell

Question 2

How do we categorize a plasmid as narrow or broad?

Answer 2

broad if it can infect a bunch of things, narrow if it can’t

Question 3

Why are plasmids selfish?

Answer 3

They live to replicate themselves

Question 4

What is a resistance plasmid/what are R factors?

Answer 4

resistance plasmid confers resistance to antibiotics and an R factor is encoded on the genome antibiotic resistance

Question 5

Whats a transposable element?

Answer 5

segments of DNA that can move itself

Question 6

What is the R factor presumptive test?

Answer 6

testing for antibiotic resistance, presumptive bc could be caused by something else in the plasmid

Question 7

Whats conjugation?

Answer 7

direct transfer of DNA from donor cell to recipient cell

Question 8

How does conjugation occur?

Answer 8

via mating bridge by genetically encoded sex pilus

Question 9

Which pilus is recognized by QB?

Answer 9

F-plasmid pilus of e.coli

Question 10

What is the FKW mutant?

Answer 10

mutant that has constitutively expressed sex pills

Question 11

Whats a bacteriocin?

Answer 11

bactericidal toxins that target cellular processes

Question 12

Whats the difference between a an antibiotic and a bacteriocin?

Answer 12

A bacteriocin is an antimicrobial peptide that can affect the same strain and an antibiotic has a wider range of infection

Question 13

What is the plasmid addiction system?

Answer 13

Plasmid encodes immunity to bacteriocin so Host wasnts to keep plasmid so it doesn’t get killed.

Question 14

Why do we expose the cell to chloroform?

Answer 14

to kill e.coli and leave the colicin

Question 15

How do we know if a strain produced colicin?

Answer 15

It has a distinct zone of clearing

Question 16

What was the negative control for colicin?

Answer 16

C600, no colicin or plasmid and is sensitive to colicin

Question 17

What is the positive control for colicin

Answer 17

MM402, has colicin

Question 18

What are we searching for in the water?

Answer 18

Fecal contamination in the form of coliform

Question 19

What are the characteristics of coliform

Answer 19

facultative anaerobes, gram negative rods, ferment lactose w acid and gas

Question 20

What test are we performing?

Answer 20

multiple tube fermentation test using most probably number of coliform present. Lactose broth is inhibits all bacteria except gram negative rods. Gas production is positive result. Presumptive test. False positives possible, non stringent media because coliforms may be stressed in water and can’t grow in scary places

Question 21

What is the presumptive water test?

Answer 21

Using laurel lysate, a nonselective broth

Question 22

What is the BGLB broth?

Answer 22

tests for fecal matter, has bile salts and toxic brilliant green agent

Question 23

What is EC broth?

Answer 23

is it a coliform, has bile salts

Question 24

What is homolactive fermentation

Answer 24

2 lactate, 2 ATP

Question 25

What is heterolactive fermentation

Answer 25

1 ATP, 1 lactate, 1 ethanol, 1 CO2

Question 26

What’s required for a cold form to be fecal

Answer 26

Must ferment lactose to produce gas when incubated at approx 44.5°