What is DNA replication and how does the cell cycle regulate cell division?

DNA replication is the production of two identical DNA strands from one original DNA molecule and is a nearly error-free process that occurs in all living organisms. This is because, in order for a cell to divide, it must first replicate its DNA. It is therefore a vital biological process and the basis for inheritence. 

Cell cycle regulator genes strictly regulate when DNA replication occurs and therefore when cell division can take place.

G0 is the resting phase of the cell cycle which occurs after mitosis, but when a cell is NOT preparing to divide again. At any one point, most cells are in the quiescent (G0) phase. G1 is the phase after mitosis and before the next round of DNA synthesis. During G1, the cell enlarges and makes new proteins. Towards the end of G1, there is a restriction point. This is for the cell to assess whether it is prepared for cell division. Once this point is passed, the cell is committed to DNA replication. S is the phase of DNA synthesis, when the new DNA is actually formed. This process takes 6-8 hours in eukaryotes and only 40min in prokaryotes. In the G2 phase, DNA is condensed into chromosomes in preparation for mitosis. Just before mitosis, there is a checkpoint which assesses if the DNA has replicated properly and whether there are any mutations requiring repair. In the M (mitotic) phase, the chromosomes actually pull apart and there is subsequent cell division.

Azeem A. GCSE Biology tutor, Uni Admissions Test -Medical School Prep...

1 year ago

Answered by Azeem, an A Level Biology tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist


Caroline J. GCSE Biology tutor, GCSE Chemistry tutor, GCSE Maths tuto...
View profile
£20 /hr

Caroline J.

Degree: Biomedical Sciences (Bachelors) - Durham University

Subjects offered: Biology, Maths+ 1 more


“About Me: I study Biomedical Sciences at The University of Durham. This course focuses on Biological systems whilst also incorporating Maths and Chemistry. I hope my tutorials will help you tolove and understand the importance of Biol...”

Jena H. GCSE Biology tutor, A Level Biology tutor, GCSE Maths tutor, ...
View profile
£20 /hr

Jena H.

Degree: Medicine (Bachelors) - Nottingham University

Subjects offered: Biology, Maths+ 1 more

-Medical School Preparation-

“I am studying Medicine and my course has helped to deepen my interest in B iology, particularly Human Biology and I aim to share this love with you in my tutorials. I am friendly and love to help others and my tutorials will be fun,  in...”

Zoe B. GCSE Psychology tutor, A Level Psychology tutor, GCSE Biology ...
View profile
£20 /hr

Zoe B.

Degree: Bsc Psychology (Bachelors) - Exeter University

Subjects offered: Biology, Psychology


“Who am I? Hi there, my name is Zoe. I am currently in my first year at the University of Exeter studying Psychology. I have for a long time had a great interest and passion for Psychology and love to read into different areas. Somethi...”

MyTutor guarantee

About the author

Azeem A. GCSE Biology tutor, Uni Admissions Test -Medical School Prep...
View profile

Azeem A.

Currently unavailable: no new students

Degree: Medicine (Bachelors) - Imperial College London University

Subjects offered: Biology, Geography+ 3 more

.BMAT (BioMedical Admissions)
-Personal Statements-

“About me: My name is Azeem Alam and I am a fourth year medical student at King’s College London. I am currently undertaking the Surgery and Anaesthesia BSc at Imperial College London. I have extensive tutoring experience and have tut...”

You may also like...

Other A Level Biology questions

What is a hormone?

How does eutrophication work?

What is the difference between natural selection and evolution?

What are the differences between facilitated diffusion and active transport?

View A Level Biology tutors


We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss