Chap 13- Viruses/ Bacteriophages

Question 1

Complex Morphology of Phages include

Answer 1

Capsid head w/ DNA- lower structure is used for attachments to host cell structure; sheath & pins (lysozymes) break host cell wall & inject viral DNA into cell

Question 2

2 Bacteriophage replication mechanisms

Answer 2

Lytic Cycle and Lysogenic (Temperate) Cycle

Question 3

Bacteriophage replication cycle that END in CELL DEATH

Answer 3

Lytic Cycle

Question 4

Bacteriophage cycle where hose cell remains alive

Answer 4

Lysogenic Cycle

Question 5

Lytic Cycle (5 steps) (APBMR)

Answer 5

Attachment (viral cell attaches to host cell) , Penetration (lysozymes BREAK cell wall/ sheath INJECTS viral DNA to host cell), Biosynthesis, (viral DNA PRODUCES more proteins/enzymes) Maturation (viral components assemble into virions @ critical concentrations), Release (phage lysozyme breaks cell wall , bursting cell & can now infect new host)

Question 6

What does phages do in lysogenic cycle?

Answer 6

viral DNA from phage becomes part of Host’s chromosomes (prophage) and turns host cell to lysogenic cell

Question 7

INACTIVE genetic material of a phage that was becomes part of host’s chromosomes ; cannot produce viral progeny

Answer 7

prophage

Question 8

What happens when prophage in lysogenic cycle is activated? (excision is spontaneous or can be caused by UV light)

Answer 8

The phage spontaneously exits host cell and cell enters lytic cycle (@ BMR steps)

Question 9

Results of Lysogeny

Answer 9

host cell immune to reinfection of same phage; host cell can exhibit new properties (phage conversion), specialized TRANSDUCTION

Question 10

change in properties of a bacteria once acquired a prophage

Answer 10

phage conversion

Question 11

type of horizontal gene transfer where virus transfer segments of DNA from one bacteria to another due to rare mistake during phage excision

Answer 11

specialized transduction

Question 12

Type of horizontal gene transfer that can occur when a phage carries a random piece of bacterial DNA due to packaging error during phage assembly

Answer 12

generalized transduction

Question 13

when phage transfers DNA from one bacteria to another

Answer 13

transduction

Question 14

How are phages grown in the lab?

Answer 14

Phages are grown in its bacterial host

Question 15

How are phages displayed on petri dish?

Answer 15

Bacterial lawns are formed & plaques are formed; Plaque forming unit (PFU) = 1 single phage; TITER- concentration of plaque in its OG sample

Question 16

Lysogenic Biosynthesis and Maturation stage

Answer 16

B- produce both new host DNA and phage DNA; M- assemble components to form virion. As host cell replicates, it will replicate the prophages also