What Happens During DNA Replication?
Part of Mitosis and the Cell Cycle — GCSE Biology
This how it works covers What Happens During DNA Replication? within Mitosis and the Cell Cycle for GCSE Biology. Cell division by mitosis, cell cycle phases, chromosome behavior, cytokinesis differences, stem cells, cancer, and practical investigations It is section 9 of 19 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 9 of 19
Practice
18 questions
Recall
18 flashcards
🧪 What Happens During DNA Replication?
Before mitosis can begin, the cell must make an exact copy of all its DNA during interphase. This is essential so that each daughter cell receives a complete, identical set of genetic information.
- The DNA double helix unwinds and the two strands separate.
- Free nucleotides pair up with their complementary bases on each strand — adenine with thymine (A-T), cytosine with guanine (C-G).
- Two identical DNA molecules are formed — each new molecule has one original strand and one new strand.
By the time mitosis begins, every chromosome has already been duplicated into two sister chromatids joined at the centromere. Mitosis simply separates these pre-made copies.