Biology: Transport Across Cell Membranes

Diffusion
1. The closer to the gas = the higher the concentration
2. Oxygen and Glucose go into the cell, Carbon Dioxide comes out the cell
3. Not all materials can diffuse
4. The higher concentration moves to the lower concentration
  1. This like a ball rolling down a hill, no energy is required
    1. This is called passive transport
Osmosis
1. Diffusion with water
2. The more water a plant absorbs, the heavier the plant is
3. Is required to get through selectively permeable membranes
  1. A membrane that can decide what goes through and what doesn't
4. Osmosis moves from high water concentration to low water concentration
  1. This is like a ball rolling down a hill, no energy is required
    1. This is called passive transport
5. In plants, if too much water is absorbed, it will make the vacoule expand
  1. This is known as a turgid cell
  2. In animals, if there is too little water, the cell will shrivel up
  3. It does not burst as plant cells have a cell wall
6. In plants, if there is not enough water, it will shrivel up
  1. Thi is known as a plasmolysed cell
7. In animals, if there is too much water, the cell will burst!
Active transport
1. This is when the low concentration moves to the high concentration
  1. Like a ball. It can't go uphill so you will have to push it. This requires energy

Resource summary

	Created by Lewis White over 11 years ago