Foundations

Cell theory describes the organization and reproduction of cellular life.

DNA's base sequence stores biological information.

Gene expression produces functional RNA or protein from gene information.

Complementary base pairing allows DNA strands to serve as copying templates.

DNA duplication, nuclear division and cytoplasmic division are distinct events in a typical mitotic cycle.

Typical diploid meiosis halves the number of chromosome sets through two divisions after one DNA replication.

A diploid individual's paired alleles can segregate into gametes.

Evolution concerns inherited change across generations.

Heritable variation can change through differences in reproductive contribution.

Chance can change allele frequencies independently of an adaptive advantage.

Evolutionary relationships describe descent from shared ancestors.

Metabolism comprises the regulated chemical reactions of living systems.

Oxygenic photosynthesis couples light-energy capture to carbon fixation and releases oxygen from water.

Aerobic respiration couples nutrient oxidation to ATP production, using oxygen as the final electron acceptor.

Selective membranes and transport proteins regulate movement between a cell and its surroundings.

Ecology examines organisms' interactions with one another and their physical environment.

Feedback can maintain internal variables within functional ranges.

Carbon moves through biological, oceanic, atmospheric and geological reservoirs.

Carbohydrates, lipids, proteins and nucleic acids organize much of cell chemistry.

Sequence, folding and assembly provide different levels of protein description.

A simple enzyme–substrate mechanism predicts saturating initial rates.

Coupled reaction pathways connect favourable chemistry with cellular work.

Mutation changes DNA sequence and can introduce inherited variation.

Movement contributes to gene flow when genetic material enters a population's reproduction.

Allele segregation and phenotype dominance are different questions.

DNA-binding regulators and cellular signals affect transcription.

DNA-associated marks can affect expression without changing DNA sequence.

Species boundaries depend on the organisms and the question being investigated.

Reduced reproductive exchange can permit populations to diverge into lineages.

Evolutionary trees are hypotheses inferred from comparative evidence.