OCR GCSE Biology A key terms

A condition in which changes in body cells cause uncontrolled growth and division.

A microscopic blood vessel with a wall one cell thick, across which substances are exchanged between blood and tissues.

A method of estimating the number of mobile organisms by marking a first sample and checking how many marked individuals appear in a second sample.

The continuous movement of carbon between living organisms and non-living parts of the environment.

The amount of carbon dioxide present in a particular volume, usually expressed as a concentration.

Specialised muscle tissue in the heart that contracts repeatedly to pump blood.

A disease affecting the heart or blood vessels.

An intensive investigation of one person or a small group, often using medical records, observations, tests and scans.

A substance that increases the rate of a chemical reaction without being used up in the reaction.

A biological process explaining how one factor can produce or contribute to an effect.

The part of a neurone containing the nucleus and most of the cell's organelles.

The growth of cells under controlled conditions outside the body.

The ordered sequence of growth, DNA replication and division through which a dividing cell passes.

The thin boundary around a cell that controls the movement of substances into and out of it.

A chemical process in living cells that releases energy from organic compounds such as glucose.

A strong layer surrounding a plant cell that supports the cell and forms a physical barrier to pathogens.

The brain and spinal cord, which process information and coordinate responses.

The region beneath the rear of the cerebrum that coordinates muscle activity, movement and balance.

The large, upper part of the brain responsible for higher-order processes including conscious thought, intelligence, memory and personality.

A non-communicable disease in which cells of the cervix grow and divide uncontrollably.

Energy associated with the arrangement of particles in a substance or reacting system, which can be transferred during a chemical reaction.

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

A sub-cellular structure in photosynthetic eukaryotic cells where photosynthesis occurs.

A structure made from DNA that carries genetic information.

Tiny hair-like structures on some airway cells that beat to move mucus towards the throat.

A ring of tissue around the lens containing muscles that alter tension in the suspensory ligaments.

The organ system in which the heart pumps blood through blood vessels to transport substances around the body.