Transport in cells

Define diffusion and eg

The passive movement of a substance from areas of high concentration to an area of low concentration e.g. perfume in a room

Define osmosis and eg

movement of water molecules from an area of low concentration to high concentration across a partially permeable membrane

Define active transport and eg

Movement of a substance from a lower conentration to a higher concentration against the concentration gradient, using energy e.g. mineral absorption by roots

Define surface area to volume ratio and e.g.

The surface area divided by the volume expressed a a ratio e.g. villi in the intestines

Factors that affect the rate of osmosis/ diffusion

High or low concentration gradient, temperature, surface area of membrane. High speeds up. Low slows down