3.1.5.2 DNA Replication Flashcards Preview

SHHS - Science - NEW AQA A-Level Biology (Year 1) > 3.1.5.2 DNA Replication > Flashcards

Flashcards in 3.1.5.2 DNA Replication Deck (18)
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1
Q

Name the Scientists who confirmed that the Semi-conservative model of DNA replication was the valid model.

A

Matthew Meselson

Franklin Stahl

2
Q

Identify the method of DNA Replication

A

Conservative DNA Replication

3
Q

Define nuclear division

A

The process by which the nucleus of a cell divides during cell division.

4
Q

Identify the type of DNA Replication

A

Dispersive DNA Replication

5
Q

Identify the method of DNA Replication

A

Semi-conservative DNA Replication

6
Q

What is the function of DNA Helicase?

A

An enzyme that breaks the hydrogen bonds between the base pairs of a DNA double helix.

7
Q

Describe the experiment that Meselson and Stahl carried out to confirm the semi-conservative method of DNA replication

A
  • Grow E. coli bacteria in 15N (heavy isotope), which is assimilated into its base pairs, causing it to have heavy DNA. Take a sample of this and ‘normal’ 14N grown E.coli
  • Allow ‘heavy DNA’ E. Coli to divide once in 14N growth medium and take a sample.
  • Allow E. Coli to divide once more in 14N growth medium and take another sample.
  • Remove DNA from each sample and perform gradient density centrifugation.
  • Check the mass of DNA present in each sample.
8
Q

Define cytokinesis

A

The process by which the whole cell divides (after nuclear division)

9
Q

Describe the process of semi-conservative DNA replication.

A
  • DNA Helicase breaks the hydrogen bonds joining the complementary base-pairs of the parent strand, forming 2 template strands.
  • Free nucleotides bind to their specific base pairs on each template strand.
  • DNA Polymerase joins the free nucleotides by forming phosphodiester bonds.
10
Q

Name the 3 models of DNA replication proposed by James Watson and Francis Crick.

A

Conservative Replication

Semi-conservative Replication

Dispersive Replication

11
Q

What is the function of free DNA nucleotides in DNA replication?

A

To bind to a separated strand of parent DNA to form a new complementary strand of daughter DNA.

12
Q

What is the function of DNA Polymerase?

A

An enzyme that joins the free daughter nucleotides bound to the parent template strands by creating phosphodiester bonds between nucleotides.

13
Q

What is required for DNA replication to take place?

A

DNA to be copied

Free DNA nucleotides

DNA Polymerase

DNA Helicase

Energy to drive the process

14
Q

What is meant by ‘semi-conservative’ DNA replication

A

DNA replication whereby each new DNA molecule contains one of the original DNA strands.

15
Q

Identify the missing label

A

Replication Fork

16
Q

name 2 enzymes involved in semi conservative replication of DNA

A

DNA helicase

DNA polymerase

17
Q

Describe the ROLE of the 2 enzymes in DNA replication

A
  1. Helicase - breaks H binds
  2. DNA polymerase joins DNA nucleotides together to reform phosphodiester bond
18
Q

give 2 features of DNA and explain how each is important for semi conservative replication

A
  1. weak H bonds to allow unzipping of 2 strands
  2. CBP to allow for accurate replication
  3. Two strands so both can act as template

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