MYP Biology Processes Key Definitions

The minimum amount of energy required for reactant molecules to start a chemical reaction.

The region of an enzyme where the substrate binds and the reaction takes place.

Living material that contains stored chemical energy.

The force that holds atoms together in molecules.

Energy stored inside the bonds of molecules such as glucose. Organisms release this energy during respiration.

Attraction between water molecules due to hydrogen bonding.

An organism that obtains energy by eating other organisms.

A system where water and blood move in opposite directions to maximize oxygen diffusion.

The breakdown of large food molecules into smaller, absorbable molecules.

Matching energy gained from food with energy the body uses.

A biological catalyst that speeds up chemical reactions by lowering the activation energy.

A nutrient the body cannot produce and must obtain through the diet.

The transfer of oxygen into the body and carbon dioxide out across a specialized surface.

Growth in response to gravity.

The control of internal conditions to keep them within safe limits.

All chemical reactions in living organisms, both building up molecules and breaking them down.

A substance in food that provides energy or materials for life processes.

Transports sucrose and organic molecules in both directions through translocation.

Growth toward or away from light.

An organism that makes its own food using an external energy source, usually sunlight.

Small openings in the leaf surface that allow gas exchange.

Transport of sucrose and other organic molecules through the phloem.

The loss of water vapor from a plant’s leaves through the stomata.

A directional growth response to a stimulus, either toward it (positive) or away from it (negative).