DNA Replication Flashcards
1
Q
Why does DNA need to replicate?
A
- making new cells for growth and repair
- passing genetic information through generations
2
Q
What are the 2 crucial enzymes involved?
A
Helicase: breaks the hydrogen bonds between nitrogenous bases
DNA polymerase: catalyses the formation of phosphodiester bonds
DNA ligase: Joins together short sections of the lagging strand
3
Q
What are the leading and lagging strands?
A
Leading: 5’-3’
Lagging: 3’-5’
4
Q
What type of replication does DNA have?
A
Semi-conservative
5
Q
What is continuous and discontinuous replication?
A
Continuous: one continuous strand is made on the template strand
Discontinuous: Okazaki fragments are made on the template strand, ligase joins them
6
Q
Explain the process of DNA replication.
A
- DNA helicase breaks hydrogen bonds between complementary base pairs
- Free nucleotides align to the complementary base pairs on each original strand
- Both original strands act as a template strand
- Hydrogen bonds reform between base pairs
- Sugar phosphate backbone forms via phosphodiester bonds
- This is catalysed by DNA polymerase
- 2 new DNA strands form, each with one original strand and one new strand
- This is called semi-conservative replication
