Cells and Transport (3)

What is simple diffusion?

The net movement of molecules from an area of high concentration to an area of low concentration down a concentration gradient

What molecules enter and leave cells via simple diffusion through the cell membrane?

Small molecules e.g. oxygen, water, glucose, amino acids

What factors affect the rate of diffusion? (3)

● Temperature

● Concentration gradient

● Surface area of cell membrane

Define osmosis

The net movement of water molecules from an area of high water concentration to an area of low water concentration down the concentration gradient through a partially permeable membrane

What is active transport?

The movement of molecules across a cell membrane from an area of low concentration to an area of high concentration, against the concentration gradient, using energy

How is a percentage change in mass calculated?

% change = (final mass -initial mass)/initial mass x100