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Biology in news
Biology as it reaches the news: DNA, RNA and proteins, cells, evolution and fossils, animal behaviour, the brain, immunity and ageing. Prelims has asked how plant and animal cells differ and what B cells and T cells do in the body.
Showing 1 of 5 subjects, those that changed from 16 to 31 August 2026.Show all
DNA replication
Copy link to DNA replicationPrelims and Mains
Before a cell divides it must copy its deoxyribonucleic acid (DNA), and that copying is mechanical work: the two strands are wound around each other and have to be pulled apart before either can be read. The enzymes that do the pulling were the subject of a study reported in August.
- The two strands pair adenine with thymine and guanine with cytosine, so each is a template for the other.
- The study found a molecular safety catch that keeps the copying apparatus inactive until a chemical signal releases it.
Unwinding
Helicase spends adenosine triphosphate (ATP) to split the double helix
Fork
A Y shaped replication fork opens where the strands part
Strain
Topoisomerases release the twisting building ahead of the fork
Copying
Each parted strand templates a new partner strand
What changed
Also filed elsewhere
- Epigenetics · on Genomics, gene editing and cell therapy
A gene is a stretch of DNA whose sequence of bases spells out one protein, and Mendel's rules have each of its two copies passed on unchanged and independently.