Grade 7-9
At the molecular level, specific enzymes carry out DNA replication:
- Helicase breaks the hydrogen bonds between base pairs, unwinding the double helix
- DNA polymerase joins new nucleotides to the template strand, building the complementary copy
- Proofreading mechanisms detect and repair errors โ a single uncorrected error becomes a permanent mutation passed to all descendants of that cell
This higher tier covers DNA Replication โ Higher Detail within Mitosis and the Cell Cycle for GCSE Biology. Cell division by mitosis, cell cycle phases, chromosome behaviour, cytokinesis differences, stem cells, cancer, and practical investigations It is section 5 of 19 in this topic. This section is most useful once the core foundation idea is secure, because it adds the detail that pushes answers higher.
Practice questions for Mitosis and the Cell Cycle
What is mitosis?
Describe what happens during interphase to prepare a cell for mitosis.
Quick recall flashcards
Define mitosis
Mitosis is the process of nuclear division that produces two genetically identical diploid cells from one diploid cell. It is used for growth and repair in multicellular organisms.
Give three reasons why cells divide
1. Growth - increasing cell numbers for organism development
2. Repair - replacing damaged or dead cells
3. Asexual reproduction - creating identical offspring