OCR GCSE Biology A key terms

The transparent, curved front surface of the eye that refracts light as it enters.

An operation that provides a new route for blood to flow around a narrowed or blocked coronary artery.

A cardiovascular disease in which the arteries supplying the heart muscle become narrowed or blocked.

The structure formed in the ovary from the remains of the follicle after ovulation; it releases progesterone.

A relationship or pattern between two variables. A correlation alone does not demonstrate that one variable causes the other.

A clear sheet placed over a specimen on a microscope slide to hold it flat for viewing.

Growing microorganisms in or on a nutrient medium under controlled conditions.

A piece removed from a plant and grown into a new plant.

The division of a cell's cytoplasm and cell membrane after nuclear division, producing two separate cells.

One of the new cells produced when a parent cell divides.

An organism, commonly a bacterium or fungus, that obtains nutrients by breaking down dead material and waste.

The breakdown of dead organisms and waste materials into simpler substances by decomposers.

A net loss of body water that leaves too little water in the blood and tissues.

The loss of an enzyme's specific three-dimensional shape, so its active site can no longer function effectively.

A permanent change in an enzyme's three-dimensional shape so that its active site is no longer complementary to its substrate.

A branched extension of a neurone that receives signals from other cells.

Blood containing less oxygen after supplying respiring body tissues.

A variable measured in response to a change in the independent variable, such as the change in mass or length of potato tissue.

The removal of stored starch from a plant before an investigation, usually by keeping the plant in darkness for about 24 hours.

Dead material from living organisms, such as fallen leaves and animal remains.

A condition in which blood glucose remains too high because insulin is absent, insufficient or less effective.

The process of identifying a disease or its cause from symptoms and tests.

The process by which an unspecialised cell develops into a specialised cell with particular structures and functions.

The overall movement of particles from a region of higher concentration to a region of lower concentration.

The distance a particle must travel by diffusion.

A cell with two sets of chromosomes, arranged in pairs.

Variation in a characteristic whose values fall into distinct categories.