Diffusion, Osmosis and Active Transport Flashcards
What is diffusion?
The net (overall) movement of particles from an area of higher concentration to an area of lower concentration.
What molecules can diffuse through cell membranes?
Only small molecules can diffuse through cell membranes e.g. glucose, amino acids, water and oxygen. Big molecules like starch and proteins can’t fit through the membrane.
What is osmosis?
The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
What is a partially permeable membrane?
A membrane with small holes in it, so only tiny molecules (e.g. water) can pass through them, and bigger molecules (e.g. sucrose) can’t.
What is active transport?
The movement of particles across a membrane against a concentration gradient (from an area of lower to an area of higher concentration) using energy transferred during respiration.
