Chapter 7

Question 1

Genome

Answer 1

ALL of the genetic material in an organism

Question 2

Initiation Site

Answer 2

specific sequence where replication is initiated

Question 3

3 types of viral primers

Answer 3

RNA
DNA (self-priming)
Protein: some RNA replication does NOT need a primer

Question 4

Primase

Answer 4

enzyme making RNA primer for DNA replication

cellular or virus-encoded

Question 5

Polymerase

Answer 5

key enzyme in genome replication
Many viruses encode own polymerase
DNA viruses that replicate in cytoplasm must encode own DdDp
RNA viruses must encode RdRp(replicase) or RdDp

Question 6

DNA Replication

Answer 6

All DNA viruses replicate genome via dsDNA
ssDNA must ->dsDNA
DNA has at least one ori (replication origin)
viral dsDNA replication is similar to cellular dsDNA replication

Question 7

2 replication modes of circular DNA

Answer 7

θ mode

σ mode: rolling circle mode

Question 8

θ mode

Answer 8

Single ori
2 replication forks
bidirectional

Question 9

σ mode

Answer 9

rolling circle mode
one strand is nicked at origin
5’ end-> peel away, as template for lagging strand
3’ end-> extend continuously
Concatemer is cut into genome length -> circularize

Question 10

dsRNA replication

Answer 10

dsRNA unwound with helicase

Semiconservative or conservative

Question 11

ssRNA

Answer 11

Must make complementary strand first
RdRp catalyzes the synthesis of both strands
Both strands must have a binding site at 3’ end for RdRp
In euk. cells, ssRNA viruses replicate genomes on membrane

Question 12

Reverse Transcription

Answer 12

Retroviruses replicate genomes via DNA intermediate
Pararetroviruses replicate genomes via RNA intermediate
Genome replication involves reverse transcription in cytoplasm
RT: as RdDp and DdDp