Biology O level/IGCSE - cell transport

In order for a cell to sustain cell activity, it needs certain substances. We shall look at how cells obtain necessary substances and get rid of unneccessary ones

Diffusion

The movement of substances from area of high concentration to that of lower concentration down the concentration gradient.

Osmosis

The movement of water (or other solvents) through a semi-permeable membrane from area of high water concentration to that of lower water concentration down the concentration gradient.

Active transport

The movement of substances from area of low concentration to that of higher concentration against the concentration gradient.

Where does energy for movement of particles in diffusion and osmosis come from?

From the kinetic energy of the particles

If temperature _____, the rate of diffusion increases

increases

The _____ the concentration gradient, the faster the rate of diffusion

greater

Where does energy for movement of particles in active transport come from?

From aerobic respiration