Molecular Biology: Dna Replication Ii

Front 1

Define:

Replication Fork

Back 1

The point at which two DNA strands are separated to allow replication to take place

Front 2

Semiconservative Replication

Back 2

Half of the parent DNA molecule is conserved in the daughter molecule, so one strand is conserved and one is newly synthesised

Front 3

DNA Dependent DNA Synthesis

Back 3

DNA synthesis that depends on a parent DNA molecule to act as a template

Front 4

Which enzyme family is required for DNA dependent DNA synthesis and in which direction is DNA synthesized?

Back 4

• DNA dependent DNA polymerases
• 5' → 3'

Front 5

What is exonuclease activity and what are the two possible types?

Back 5

• Activity that degrades DNA
• 5' → 3'

polymerase removes DNA already attached to the template

• 3' → 5'

polymerase removes nucleotides it has just inserted (proofreading)

Front 6

Why do single strands need to be protected and what proteins perform this function?

Back 6

Singles strands are protected by single strand binding proteins to prevent

• nucleotides reattaching
• attack by nucleases (present in the cell to attack single stranded virus DNA)

Front 7

What are primers and what makes them?

Back 7

A RNA nucleotide sequence needed for DNA polymerase III to start DNA synthesis.

It is made by primase, an RNA polymerase

Front 8

How does the priming process differ in eukaryotes?

Back 8

• After the RNA primer is made, DNA pol αdds about 20 nucleotides before DNA pol δ synthesises the rest of the new strand