AQA GCSE Biology key terms

A feature of an organism, such as disease resistance, milk yield or temperament.

The green pigment in chloroplasts that absorbs light energy for photosynthesis.

A subcellular structure in plant cells where photosynthesis takes place.

The yellowing of normally green plant tissue because too little chlorophyll is present.

A thread-like structure made from DNA and found in the nucleus of a cell; chromosomes carry genes.

Tiny hair-like structures on specialised cells that move mucus towards the throat.

A ring of muscle in the eye that contracts or relaxes to alter the tension on the lens.

The organisation of organisms into groups according to shared characteristics and relationships.

A long-term change in climate patterns, including temperature and rainfall.

Testing of a potential drug using healthy volunteers and patients.

An organism or cell that is genetically identical to another organism or cell from which it was produced.

A large number written before a chemical formula to show how many molecules or formula units take part.

An ancestral organism from which two or more groups of organisms evolved.

A disease that can spread between organisms and is caused by a pathogen.

All the populations of different species living together in a habitat.

The struggle between organisms for resources they both need when those resources are limited.

Partly decomposed biological material used as a natural fertiliser for plants and crops.

A lens that is thinner in the middle than at the edges and spreads out, or diverges, light rays.

A difference in the concentration of a substance between two regions.

A factor associated with both the factor being investigated and the outcome, which may provide an alternative explanation for an observed relationship.

The protection and careful management of species and habitats to maintain biodiversity.

An organism that obtains food by eating another organism.

The unwanted presence of microorganisms that were not intended to be in a culture.

Removing and testing small samples repeatedly while a reaction is taking place.

The use of a method or device to prevent pregnancy.

A factor kept the same so that it does not provide another explanation for a difference in results.

A lens that is thicker in the middle than at the edges and brings light rays together, or converges them.