OCR GCSE Combined Science B key terms

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

A subcellular structure in plant cells in which photosynthesis takes place.

One of the two identical copies of a replicated chromosome, joined together before they separate during cell division.

The pattern of separated substances produced by chromatography.

A technique that separates dissolved substances because they move differently between a stationary phase and a mobile phase.

A structure made of DNA that carries genes.

The heart, blood and blood vessels that transport substances around the body.

The organisation of organisms into groups based on similarities and differences.

A numerical range used to group measurements, with boundaries that determine which values belong in it.

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

Testing a potential medicine in human volunteers and patients to investigate its safety, effectiveness and suitable dose.

A complete conducting path around which charge can flow.

A system in which no energy is transferred across its boundary to or from the surroundings.

A number placed before a chemical formula in an equation, multiplying the whole formula.

The explanation that reacting particles must collide with sufficient energy for a reaction to occur.

Burning in which a fuel reacts with oxygen and releases energy.

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

A disease caused by a pathogen that can be transmitted between organisms.

All the populations of different species living in the same area.

A living cell alongside a phloem sieve-tube element that supports its functions.

An interaction in which organisms need the same resource but its supply is limited.

A material made by combining two or more materials to obtain useful properties.

A substance containing two or more different elements chemically bonded together in fixed proportions.

A region of a longitudinal wave where particles are closer together than usual.

The maximum compressive force per unit area that a material can withstand before failing.

A model in which a computer applies rules or calculations to investigate how a system behaves.

An acid solution containing a relatively large amount of acid in a given volume of solution.