Biological Molecules Nucleic Acid DNA Replication Flashcards Preview

As-Level Biology > Biological Molecules Nucleic Acid DNA Replication > Flashcards

Flashcards in Biological Molecules Nucleic Acid DNA Replication Deck (18)
Loading flashcards...

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

Matthew Meselson

Franklin Stahl


Identify the method of DNA Replication

Conservative DNA Replication


Define nuclear division

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


Identify the type of DNA Replication

Dispersive DNA Replication


Identify the method of DNA Replication

Semi-conservative DNA Replication


What is the function of DNA Helicase?

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


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

  • 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.


Define cytokinesis

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


Describe the process of semi-conservative DNA replication.

  • 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.


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

Conservative Replication

Semi-conservative Replication

Dispersive Replication


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

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


What is the function of DNA Polymerase?

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


What is required for DNA replication to take place?

DNA to be copied

Free DNA nucleotides

DNA Polymerase

DNA Helicase

Energy to drive the process


What is meant by 'semi-conservative' DNA replication

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


Identify the missing label

Replication Fork


name 2 enzymes involved in semi conservative replication of DNA

DNA helicase

DNA polymerase


Describe the ROLE of the 2 enzymes in DNA replication

1. Helicase - breaks H binds

2. DNA polymerase joins DNA nucleotides together to reform phosphodiester bond


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

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

Decks in As-Level Biology Class (43):