OCR GCSE Combined Science A key terms

A solution used to keep the pH of a reaction mixture approximately constant.

A property of a material containing many particles acting together, such as melting point, electrical conductivity or malleability.

Checking and adjusting an instrument using reference samples with known values, such as solutions of known pH.

A disease in which changes in cells cause uncontrolled growth and division.

A substance being investigated because it might be useful as a medicine.

A tiny blood vessel with a wall one cell thick, adapted for exchanging substances between blood and tissues.

A narrow tube in a bubble potometer in which the movement of an air bubble can be measured.

Breeding animals in captivity to help conserve their species, potentially providing individuals for release into the wild.

A method of estimating an animal population by marking and releasing a first sample, then recording the proportion of marked animals in a second sample.

An enzyme that catalyses the breakdown of carbohydrates into smaller sugars. Amylase is a carbohydrase that breaks down starch.

An organic molecule containing carbon, hydrogen and oxygen. Carbohydrates include simple sugars and larger molecules such as starch.

A compound containing carbonate ions, $\mathrm{CO_3^{2-}}$; metal carbonates react with acids to produce a salt, water and carbon dioxide.

Trapping carbon dioxide from industrial processes and storing it, for example deep underground, to prevent its release into the atmosphere.

A sequence of carbon atoms joined together by covalent bonds.

The continuous movement of carbon between organisms and the environment through processes including photosynthesis, feeding, respiration, decomposition and combustion.

The amount of carbon dioxide in a given volume of air or solution.

The total greenhouse gas emissions associated with the full life cycle of a product, service or event.

A colourless, odourless, poisonous gas, $\mathrm{CO}$, which binds to haemoglobin and reduces the blood's ability to carry oxygen.

A closed loop of carbon atoms joined together by covalent bonds.

A process or store that takes up carbon dioxide from the atmosphere, such as growing vegetation or the oceans.

A substance or exposure that can cause cancer.

The muscle tissue in the heart wall that contracts rhythmically to generate pressure and pump blood.

A disease affecting the heart or blood vessels.

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

A variable consisting of groups or labels, such as material type or species.

The negative electrode in electrolysis, towards which positive ions move.

A positively charged ion.