Bacterial and Viral Genetics

Question 1

4 types of bacterial genetics?

Answer 1

1) Transformation
2) Conjugation
3) Transposition
4) Transduction

Question 2

Transformation?

Answer 2

Ability to take up naked DNA from lysed cells from environment (also known as “competence”)

Question 3

Which bacteria undergo transformation?

Answer 3

SHiN

Question 4

What happens if you add deoxyribonuclease to environment with naked DNA in medium?

Answer 4

Naked DNA will degrade and no transformation will occur

Question 5

F+ plasmid?

Answer 5

Contains genes required for sex pilus and conjugation

Question 6

F- bacteria?

Answer 6

Bacteria without the plasmid

Question 7

What is a plasmid?

Answer 7

dsDNA

Question 8

F+ x F-?

Answer 8

Plasmid is replicated and transferred thru pilus from F+ to F- bacteria (NO transfer of Chr genes occurs)

Question 9

High frequency recombination (Hfr) cell?

Answer 9

F+ plasmid becomes incorporated into bacterial Chr DNA

Question 10

Hfr x F-?

Answer 10

Trasnfer of plasmid and Chr genes occurs

Question 11

Conjugation?

Answer 11

F+ x F- and Hfr x F-

Question 12

Transposition?

Answer 12

Segment of DNA that can “jump” (excision and reintegration) from one location to another, can trasnsfer genes from plasmid to Chr and vice versa

Question 13

Transduction?

Answer 13

1) Generalized

2) Specialized

Question 14

“Packaging” event?

Answer 14

Generalized transduction

Question 15

“Excision” event?

Answer 15

Specialized transduction

Question 16

Uses lytic phage?

Answer 16

Generalized

Question 17

Uses lysogenic phage?

Answer 17

Specialized

Question 18

Generalized?

Answer 18

Lytic phage infects bacterium leading to cleavage of bacterial DNA, bacterial DNA is packaged in viral capsid and phage then infects another bacterium transferring these genes

Question 19

Specialized?

Answer 19

Lysogenic phage infects bacterium and viral DNA incorporates into bacterial Chr, phage DNA is excised along with some bacterial DNA, mixed DNA is packaged into viral capsid and infects another bacterium

Question 20

5 bacterial toxins encoded in a lysogenic phage?

Answer 20

ShigA-like toxin
Botulinum toxin
Cholera toxin
Diphtheria toxin
Erythrogenic toxin of GAS

Question 21

Recombination?

Answer 21

Exchange of genes bt 2 Chrs by crossing over within regions of significant base sequence homology

Question 22

Reassortment?

Answer 22

Viruses with segmented genomes exchange segments–causes worldwide influenza pandemics

Question 23

Complementation?

Answer 23

When 1 of 2 viruses that infect the cell has a mutation that results in a nonfunctional protein

Question 24

How does complementation produce a functional protein?

Answer 24

The nonmutated virus “complements” the mutated one by making a functional protein that serves both viruses

Question 25

Phenotypic mixing?

Answer 25

Occurs with simultaneous infection of cell with 2 viruses

Question 26

MOA of phenotypic mixing?

Answer 26

1) Genome of virus A is coated with surface proteins of virus B producing a pseudovirion
2) Type B protein coat determines infectivity
3) However, progeny have type A coat that is encoded by its type A genetic material