DNA replication

Question 1

What does mitosis produce

Answer 1

Two genetically identical diploid cells

Question 2

What does meiosis produce

Answer 2

4 Genetically different haploid cells

Question 3

What is the role for DNA helicase in DNA replication?

Answer 3

It untwists and unwinds the DNA by breaking the hydrogen bonds between complementary base pairings

Question 4

What is DNA polymerase

Answer 4

It is an enzyme that catalyses the formation of phosphodiester bonds, from the 3’ OH end to the 5’ end.

Question 5

What is Ligase

Answer 5

An enzyme (usually only found in the lacking strand) which joins up nucleotides by adding individual phosphodiester bonds in spaces left by the Primase.

Question 6

What is the role of DNA primase

Answer 6

Attaches to the DNA to initiate replication

Question 7

How does DNA replicate (7 marks)

Answer 7

semi-conservative (replication) ;
(double) helix, untwists / uncoils / unwinds / unravels ;
DNA helicase breaks hydrogen bonds (between bases) break ;
each strand acts as the template
(for the formation of a new molecule) ;
free (DNA) nucleotides (align with exposed bases)
complementary base pairing / purine to pyrimidine ;
hydrogen bonds (re)form ;
sugar-phosphate backbone/adjacent nucleotides join forms done by DNA ligase
DNA polymerase joins , backbone / strands ;
each new molecule has 1 old and 1 new strand ;
AVP ;