C3.1 Plant Signalling (HL)

Flashcards covering key concepts related to Plant Signalling, including definitions of terms related to cell signalling, phytohormones, and plant tropisms.

Cell Signalling

The transmission of chemicals between cells, initiated by a chemical messenger called a ligand.

Ligand

A chemical messenger released from a communicating cell that binds to a receptor.

Receptor

A protein that has complementary binding sites to ligands and undergoes conformational changes upon ligand binding.

Phytohormones

Chemical messengers that control growth, development, and response to stimuli in plants.

Auxin

A type of phytohormone involved in growth and elongation, activating proton pumps to influence cell wall flexibility.

Auxin Efflux Carriers

Proteins that transport auxin out of the cell to create concentration gradients.

Tropisms

Growth or turning movements of plants in response to directional stimuli.

Phototropism

A growth movement of plants in response to unidirectional light, causing them to bend towards the light.

Cytokinin

A phytohormone produced in roots that promotes cell division and regulates plant growth in conjunction with auxin.

Positive Feedback

A process where the output (e.g., fruit ripening) reinforces the stimulus (e.g., ethylene production) for more rapid results.