Biology key terms

A measure of the tendency of water molecules to move from one region to another.

The absorption of water from the soil into a plant, mainly through root hair cells by osmosis.

The difference in water vapour concentration between two places; a steeper difference increases the rate of diffusion.

A tough, waxy layer covering the surface of a leaf that helps prevent microorganisms entering.

The state of being comfortable, healthy and able to function physically, mentally and socially.

A nucleated blood cell that helps defend the body against pathogens.

Determining the base sequence across an organism’s complete genome.

The total mass against which the mass of a substance or part is compared.

A plant adapted to survive where water is scarce.

A disorder caused by a recessive allele located on the X chromosome.

Plant transport tissue that carries water and mineral ions from the roots towards the leaves.

A long conducting tube formed from dead xylem vessel elements joined end to end.

The amount of crop or other agricultural product produced, often measured per unit area.

A clear area around a treatment disc on an agar plate where bacterial growth has been prevented.

The cell formed when two gametes join at fertilisation.