2.14 DNA Replication

Question 0

3 requirements for DNA Polymerases

Answer 0

1. 5’triphosphates of the A,T,C and G deoxynucleosides must be present
2. Preexisting single strand of DNA to be replicated (Template strand)
3. A RNA Primer must be present and hydrogen bonded to template strand

Question 1

What are the 5 rules of DNA replication

Answer 1

1. Semi-Conservative
2. Occurs from origins of replication
3. Is Bidirectional
4. Strands are extended from 5’ –> 3’
5. Requires an RNA Primer

Question 2

What does processivity mean?

Answer 2

Means that the template is held to the replication area for a long time. DNA Polymerases do not release template until it has processed for a while.

Question 3

What does Fidelity mean?

Answer 3

Corresponds to accuracy.

Question 4

Describe the sliding clamp that ensures high processivity

Answer 4

1. Clamp loading protein (RFC) binds DNA between primer and template
2. PCNA (proliferating Cell Nuclear Antigen) binds and allows for DNA Polymerase to bind.
   PCNA prevents early release of polymerase from template

Question 5

What enzyme splices Okazaki fragments together

Answer 5

DNA Ligase

Question 6

What enzyme is the only one that can work with Nucleoside Monophosphates

Answer 6

DNA Ligase

Question 7

How does Helicase work?

Answer 7

It opens DNA at replication fork by breaking Hydrogen bonds

Question 8

What enzyme removes the RNA Primer in telomerase activity

Answer 8

RNase