Biology key terms

A knot of capillaries inside Bowman’s capsule where blood is filtered under pressure.

A hormone released by the pancreas when blood glucose is too low; it causes stored glycogen to be converted to glucose and released into the blood.

A soluble sugar produced by photosynthesis and used as a respiratory substrate or as the starting material for other biological molecules.

A three-carbon alcohol that forms the central backbone of a triglyceride.

A carbohydrate made from glucose and stored mainly in liver and muscle cells.

A bacterial sexually transmitted infection that can cause a thick yellow or green discharge and pain when urinating.

The change in the vertical-axis quantity divided by the corresponding change in the horizontal-axis quantity.

A directional growth response to gravity; also called geotropism.

A gas in the atmosphere that absorbs outgoing long-wavelength radiation and helps keep Earth warm.

A permanent increase in the size or dry mass of an organism.

A nutrient material, such as agar jelly, on or in which microorganisms can grow.

The process of taking and plotting repeated measurements to identify a pattern over time.

One of a pair of cells surrounding a stoma that controls whether the pore is open or closed.

Pairs of cells around stomata that control whether the pores are open or closed.

The natural environment in which an organism lives.

The destruction or removal of the place where an organism normally lives.

An iron-containing protein in red blood cells that binds reversibly to oxygen.

A serious illness involving fever and bleeding.

Having a single set of chromosomes: half the number found in a body cell of the same species.

Something with the potential to cause harm, such as a hot water bath, broken glass or a harmful microorganism.

Human chorionic gonadotropin, a hormone that can be detected in urine during pregnancy.

A state of physical and mental well-being, rather than simply the absence of disease.

An organ made of muscle that pumps blood through the lungs and around the rest of the body.

A condition in which the heart cannot pump blood around the body effectively enough.

The number of heartbeats in a given time, usually measured in beats per minute (bpm).

The surgical replacement of a failing heart with a suitable heart from a donor.

A flap-like structure that opens to let blood move forwards and closes to prevent it flowing backwards.