DNA Replication Flashcards
What is DNA replication?
It is the process by which the cell doubles the quantity of DNA to prepare for division.
When does DNA replication occur?
It occurs during the interphase (S phase).
True or false; DNA replication is semi-conservative?
True
Why is DNA replication semi-conservative?
DNA replication is semi-conservative as both of the DNA molecules produced are formed from an ‘old’ strand and a ‘new’ one. The new strands formed are complementary to their template strands.
What 2 molecules are involved in DNA replication?
DNA replication enzymes and free floating nucleotides
How many DNA replications enzymes are there and what are they?
4 main enzymes: Helicase, DNA polymerase, Primase, Ligase
What are the steps in DNA replication?
- DNA unzips
- Nitrogen bases in the cell nucleus pair up with the bases in the DNA halves
- Two dentical DNA molecules are formed
True or false; The two new DNA molecules produced are not identical to each other
False
How are the two DNA molecules identical?
The two DNA molecules produced are identical to each other as they have the same base sequence.
What could happen if there was a mistake in the order of bases?
A mistake in the order of bases may result in a mistake in gene expression, which could be detrimental (even fatal) to the cell or organism.
What does the enzyme helicase do?
Helicase unwinds the double helix and separates the two strands by breaking hydrogen bonds.
What does the enzyme DNA polymerase do?
DNA polymerase links nucleotides together to form a new strand, using the pre-existing strand as a template and ensuring complementary base pairing. The free nucleotides form hydrogen bonds with their complimentary base pairs on the template strand. Adenine will pair up with thymine and guanine will pair up with cytosine.
What does the enzyme primase do?
Primase make the primer so that the DNA polymerase can
figure out where to go to start to work.
What does the enzyme ligase do?
Helps glue the DNA fragment together.
