Edexcel GCSE Combined Science key terms

A positively charged ion. A metal atom forms a cation by losing electrons.

Growing cells in controlled laboratory conditions.

The sequence of events in which a cell grows, copies its DNA and divides into two daughter cells.

The process by which a cell develops specialised structures that enable it to carry out a particular function.

The production of new cells from an existing cell. In growth, division involving mitosis increases the number of body cells.

An increase in a cell's length, which contributes to growth in plants.

The boundary of a cell that controls which substances enter and leave.

The chemical reactions occurring continuously in living cells that break down nutrient molecules, such as glucose, to release energy for metabolic processes.

A strong layer outside the cell membrane that supports the cell. Plant cell walls are made of cellulose.

The brain and spinal cord, which coordinate responses to incoming information.

The resultant force towards the centre of a circle that keeps an object moving in a circular path.

A change in which different substances are formed.

A substance produced by the body that destroys pathogens or inhibits them through chemical action.

A representation of a substance using element symbols and subscripts to show its composition. For an ionic compound, it shows the simplest whole-number ratio of its ions.

Very unreactive chemically under ordinary conditions.

The addition of chlorine to water to kill harmful bacteria and other microorganisms.

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

An organelle containing chlorophyll that absorbs light for photosynthesis.

One of the two identical copies joined together in a chromosome after its DNA has been copied.

The pattern of separated substances produced by chromatography.

The main DNA molecule carrying a cell's genetic information; in bacteria it is circular and lies in the cytoplasm.

A structure made from a long DNA molecule, found in the nucleus of a cell. Chromosomes carry genes.

Microscopic hair-like structures on cells lining the airways that beat to move mucus towards the throat.

An automatic safety switch that opens the circuit when the current becomes too large and can be reset after the fault is corrected.

The organisation of living organisms into groups based on shared characteristics and evolutionary relationships.

A long-term change in climate, including average temperatures and patterns of rainfall.

A study that tests a potential treatment in human volunteers or patients.