Higher Biology

The double helix in more structural detail, and how a cell copies its DNA accurately before dividing.

How RNA differs from DNA, how a gene's code is transcribed and translated into a protein, and how one gene can produce more than one protein.

How a single change to DNA's base sequence can alter, or fail to alter, the protein a gene produces.

Larger-scale changes to a chromosome's structure, changing several genes at once rather than a single base.

What sequencing an entire genome makes possible, from tracing evolutionary history to personalised medicine.

How enzymes are controlled and inhibited within a metabolic pathway.

The three stages of aerobic respiration, where each happens in the cell, and why oxygen is needed at all.

Why NAD must be regenerated without oxygen, and how metabolic rate is measured and compared.

How the hypothalamus uses negative feedback to keep an endotherm's body temperature stable.

How migration, dormancy, and rhythmic behaviour help organisms survive conditions they cannot control.

The trade-offs involved in producing enough food for a growing population without exhausting resources.

The light-dependent and light-independent stages, and the named molecules that carry carbon around the cycle.

Close relationships between species, and the costs, benefits, and complexity of living in a social group.

Where genetic variation actually comes from, and how isolation splits one species into two.