Biology key terms

A community in which species and environmental factors are in balance, so population sizes remain fairly constant.

A coloured chemical used to increase contrast so that otherwise colourless cell structures are easier to distinguish.

A person or group that is affected by, can influence, or has an interest in a decision.

A way of writing a number as $a\times10^n$, where $1\leq a<10$ and $n$ is an integer.

The level of material comfort experienced by a person or population, associated with the quantity of goods and services used.

An insoluble carbohydrate into which plants convert glucose for storage.

A chemical test in which iodine solution changes from orange-brown to blue-black when starch is present.

A type of drug used to lower blood cholesterol, slowing the build-up of fatty material in arteries.

A cell that has not yet become specialised and can divide to produce more stem cells and cells that differentiate into specialised types.

Unspecialised cells that can divide and develop into specialised types of cell.

The use of stem cells, or specialised cells produced from them, to replace damaged or missing cells in a patient.

A small tube inserted into an artery to hold it open and allow blood to flow through.

The complete killing or removal of microorganisms from an object or material.

A short, unpaired stretch of bases at the end of a cut DNA fragment that can pair with a complementary end.

Short, single-stranded ends of DNA whose unpaired bases can pair with complementary bases on another DNA fragment.

A change in the internal or external environment that can be detected by a receptor.

A small pore in a leaf through which gases move; its opening is controlled by guard cells.

Tiny pores in a leaf's surface through which gases and water vapour can pass.

A part of a cycle in which a substance is held, such as the atmosphere, an ocean, soil or living biomass.

A genetically distinct form within a species, such as a bacterial form with resistance to a particular antibiotic.

One of the two long, continuous chains that form a DNA molecule.

The study of the order and relationships of layers of rock or sediment, used to work out which finds are relatively older or younger.

The volume of blood pumped out of a ventricle during one heartbeat, usually measured in millilitres per beat.

A physical feature of an organism’s body that helps it survive.

An image showing physical features such as the position, shape and density of tissues.

Abnormally slow or limited plant growth.

A structure inside a cell that performs a particular function.