AQA GCSE Biology key terms

The number of organisms of a species in an area, or an estimate such as the percentage of ground they cover.

The change in lens shape that focuses light from near or distant objects onto the retina.

Rain made more acidic than normal when acidic gases such as sulfur dioxide, released by burning coal and oil, dissolve in it. It can damage leaves, acidify lakes and erode buildings.

A characteristic developed because of environmental conditions rather than inherited genetic information.

The region of an enzyme to which its substrate binds.

The movement of substances against a concentration gradient using energy released by respiration.

A feature or behaviour that helps an organism survive and reproduce in the conditions where it lives.

A hormone released by the pituitary gland that increases the permeability of kidney tubules to water.

A hormone released by the adrenal glands during fear or stress that prepares the body for rapid action.

A cloning method in which the nucleus of an adult body cell is inserted into an egg cell whose own nucleus has been removed.

A stem cell retained in a mature animal; adult stem cells in bone marrow can form many cell types, including blood cells.

Respiration that uses oxygen and completely oxidises glucose.

A person who displays the characteristic or disorder being followed in a pedigree.

The materials and resources used in farming, such as fertilisers, pesticides, machinery, fuel, seed and animal feed.

The late stage of HIV infection, when the immune system is so badly damaged that it cannot deal effectively with other infections or cancers.

A form of a gene. Different alleles contribute to genetic variation within a population.

The proportion of all copies of a gene in a population that consist of a particular allele.

A tiny air sac in the lungs where oxygen enters the blood and carbon dioxide leaves it.

A small molecule that is joined to others in a particular order to form a protein chain.

A toxic nitrogen-containing substance formed when excess amino acids are deaminated in the liver.

A carbohydrase that breaks down starch into maltose.

Decay that occurs without oxygen and can produce methane.

Respiration that transfers energy from glucose without using oxygen.

A result that is noticeably different from the other repeated results.

A medicine that kills bacteria or inhibits their growth; antibiotics do not treat viral infections.

The ability of a bacterium to survive or continue growing when exposed to an antibiotic that would normally kill it or inhibit it.

A protein made by white blood cells that binds specifically to an antigen.