Edexcel GCSE Biology key terms

A soluble nitrogen compound that plants absorb from soil through their roots and use to make amino acids and proteins.

The conversion of ammonium compounds into nitrites and then nitrates by bacteria in soil.

The movement and chemical transformation of nitrogen between the atmosphere, soil and living organisms.

The conversion of nitrogen gas from the air into nitrogen-containing compounds by nitrogen-fixing bacteria.

DNA whose base sequence does not code for the amino acid sequence of a protein; some non-coding regions help control gene expression.

A disease that is not caused by a pathogen and cannot be passed from one person to another, although its risk factors may be common across a population.

A species introduced to an area where it does not naturally occur.

A subunit of DNA consisting of a sugar, a phosphate group and one of four bases.

A structure in a eukaryotic cell that contains genetic material and controls the cell's activities.

The amount of a particular object or event, usually found by counting.

A chronic condition involving excessive body-fat deposits and arising through interactions among energy balance, behaviour, genetics and the wider environment.

An ovarian hormone that repairs and thickens the uterus lining, inhibits FSH and stimulates LH release when its concentration becomes high.

An infection that takes advantage of a weakened immune system and would normally be controlled more effectively.

The condition, such as a particular temperature or pH, at which an enzyme-catalysed reaction has its maximum rate.

The temperature at which a process reaches its highest rate under the conditions being considered.

Spread of a pathogen when it enters another person's body through the mouth.

The power of ten that best describes the approximate size of a value.

The regulation of water and dissolved ion levels in body fluids.

The net movement of water through a partially permeable membrane from a more dilute solution to a more concentrated solution.

The release of a mature egg from an ovary.

A layer of closely packed leaf cells near the upper surface, containing many chloroplasts.

Loss of the ability to move some or all muscles, often because communication through part of the nervous system has been disrupted.

An organism that lives in or on an organism of another species and gains resources from it, harming that organism.

An interaction between two different species in which one organism benefits and the other is harmed.

A barrier that allows some substances to pass through but prevents others from passing through.

A transport process that does not require energy from respiration.

A disease-causing microorganism, such as a bacterium, virus, fungus or protist.