M6: Bacteriophages Overview

Question 1

bacteriophage

Answer 1

type of virus that infects bacteria

Question 2

unique structure of bacteriophage

Answer 2

• icosahedral capsid head group

- helical tail w/tail fibers attached

Question 3

icosahedral

Answer 3

20-sided polygon

Question 4

tail fibers

Answer 4

fibrous extensions that aid in binding to host cells

Question 5

2 forms of replication for bacteriophages

Answer 5

1) lytic replication

2) lysogenic (temperate) replication

Question 6

lytic replication

Answer 6

bacteriophage replicates in host cell until host cell ruptures & is destroyed

Question 7

viral titer

Answer 7

amount of virus in a culture

Question 8

lysogenic replication

Answer 8

• bacteriophage exists in non-replicative state within host cell
• viral genome integrated into host genome –> when host replicates DNA, viral genome also replicated

Question 9

turbidity

Answer 9

cloudiness

Question 10

lytic replication in lab

Answer 10

• media will start w/high degree of turbidity and slowly become clear as more host cells are lysed
• need to carefully control viral titer so host cells aren’t destroyed too quickly but also doesn’t take too long for virus culture to grow

Question 11

prophage

Answer 11

bacteriophage that has integrated into host genome via lysogenic replication

Question 12

what keeps lysogenic replication from destroying host cell?

Answer 12

viral protein production is supressed

Question 13

impact of stress conditions on prophage

Answer 13

reactivates –> full replication of viral proteins –> lytic replication cycle