Biol 300 Class 2.3: DNA Replication Diagram | Quizlet

What are the two types of DNA Synthesis?

Synthesis involved in Replication and Synthesis involved in Repair

Is every Polymerase involved in replication?

Not all polymerase is involved in replication.

What is replicase?

DNA pol that can synthesize a new DNA strand on a template

What arethe DNA Polymerases found in E. Coli?

1. polA

2. polB

3. polC

4. dinB

5. umuD2C

TERM

What is the function of polA?

DEFINITION

It replaces primers in Okazaki Fragments, major repair enzyme

What is the function of polB?

Replication restart when forks stalls at damaged site

TERM

What is the function of polC?

DEFINITION

MAJOR replicase, part of large transient complex replisome

What is the function of dinB and umuD2C?

Translesion replication, Repair; synthesize DNA using template strand that contains the damaged bases

What is the error rate of DNA Replication?

~10^-3 per nucleotide replicated

What are the two types of errors that DNA Replication can make?

1. Frameshifts

2. Substitutions

What causes Frameshift mutations?

When an extra nucleotide is added or a nucleotide is removed; this is often prevented because the enzyme is processive. Most common in homopolymeric regions which can cause slippage

What causes Substitution Mutations?

A wrong nucleotide is incorporated; rate of error depends on proofreading. It is easily fixed on new strands

What is the function of Proofreading?

All DNA Polymerase has its own 3'-5' exonuclease activity

Describe synthesis of two DNA Strands

Replication is semi conservative and semi discontinuous, it is synthesized from 5' to 3' and the leading strand is continuous while the lagging strand is discontinuous.

What is the common way to show Core Enzyme Domains of Polyermase?

Analogous to human right hand, Palm is the catalytic active site, Fingers are what positions the template correctly in the active site, and the Thumb binds DNA as it exits the enzyme Processivity.

What is Exonuclease Activity? How does it occur?

This is editing, it occurs in the 3 to 5 direction

What is the N-Terminal domain for during replication?

It acts as a spacer between Polymerase and exonuclease domains.

What is the Catalytic Core of DNA Pol 3 comprised of?

Alpha Subunit, Epsilon Subunit, and Theta Subunits

What is the function of DNA Pol 3 Alpha Subunit?

It is responsible for DNA Binding and Polymerase Activity (Palm Fingers Thumb and N Spacer)

What is the function Dimerizing Subunit for DNA Pol 3?

AKA Tau Subunit, it links the two cores together

What does the Clamp do in DNA Pol 3?

It holds the Pol 3 Catalytic Core onto the DNA Template; they are Homodimers of the Beta subunit and binds around DNA ensuring processivity

What is the Clamp Loader in DNA Pol 3?

AKA The Gamma Complex which consists of 5 proteins needed to place and release the clamp on DNA

What are the three stages of the Holoenzyme Assembly?

1. Clamp loader Hydrolyzes ATP

2. Binding of DNA changed conformation

3. The Tau Dimer binds the core

What is the Dipolymerase Model?

Explains how the leading strands and lagging strands are synthesized at the same time. Two Catalytic Cores

TERM

What Unwinds DNA at the replication fork?

DEFINITION

DnaB otherwise known as DNA Helicase.

TERM

What prevents Pol 3 dissociating from DNA?

DEFINITION

The DNA Clamp

TERM

What provides the RNA Primer?

DEFINITION

DnaG otherwise known as Primase