Glossary

A

Abiotic: non-living factors such as wind, water or temperature

Auxin: plant hormones that control cell elongation

Chromophore: a pigment molecule which absorbs light

Control group: a group within an experiment that receives no treatment from the researchers, so that treated groups can be compared

Exudates: substances secreted by an organ, in this case plant roots

Gene: a section of DNA which acts as a set of instructions for certain cell functions e.g. protein synthesis

Herbicide: a substance used to kill unwanted vegetation

Hormone: chemical messengers that regulates growth and development

Organic compounds: Chemical compounds, which make up the majority of living organisms e.g. proteins

Pathogen: a disease causing organism

Pesticide: chemical compounds which target and kill species considered pests

Photoreceptors: a type of protein that is specialised to perceive and respond to light

Photosynthesis: The process by which plants convert light energy into chemical energy, producing organic compounds rich in energy

Phototropism: plant growth in response to a directional light source

Pollinator: An organism which carries pollen from one flower to another

Receptors: cells which detect environmental change and respond to the change

Soluble: a substance that dissolves

Species: a group of similar organisms which are able to breed and produce fertile offspring

Stimulation: action which increases the levels of activity in the body or in biological systems

Stimulus: a change in the environment that can be detected by an organism

Thigmonasty: a non-directional response to touch which is unaffected by the direction of the stimulus

Thigmotropism: a directional response to touch towards the stimulus

VOC's: organic chemical molecules which are emitted as a gas