Describe the process of DNA replication

DNA replication is semi-conservative, meaning existing strands are used as templates for new strands. The DNA is separated (unwinds) by the enzyme helicase. This enzyme breaks the H bonds between nucleotides. Topoisomerase breaks the DNA ahead of the opening of the replication fork before it gets to tight (to reduce tension). An enzyme called primase starts a short RNA chain from scratch using RNA nucleotides. Now DNA polymerase can build the new DNA strand using complementary base pairing (Adenine - Guanine, Cytosine - Uracil) in the 5' to 3' direction.
The second strand is built up by joining segments called Okazaki fragments using the enzyme DNA ligase. This occurs in the 3' to 5' direction and makes phosphodiester bonds.
This results in the formation of 2 identical DNA complexes.

KO
Answered by Katherine O. Biology tutor

2403 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

During succession the species present changes. Explain why.


Draw a graph on the effect of an increase in temperature on the rate of an enzyme controlled reaction. Explain the shape of the curve and suggest why the temperature of a mammal is maintained just below the optimum temperature.


Explain the sequence of events that occur in the control of the cardiac cycle.


How is the concentration of sodium altered in a cell in the intestines and why is glucose absorption affected?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences