Cell transport

• Transport proteins that assist with diffusion create concentration gradients to drive the movement of molecules.
• Osmosis is the movement of water molecules across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration until equilibrium is reached.
• What is osmosis?

  Movement of water molecules through a semi permeable membrane
• Active Transport - requires energy (ATP) to move against its concentration gradient
• The rate of diffusion depends on temperature, surface area and concentration gradient
• Diffusion is the net movement of particles from an area of high concentration to an area of low concentration
• Active processes require energy input
• Passive Processes do not require energy input
• Passive Processes do not use ATP or any other form of energy
• In diffusion, particles move randomly
• Anaerobic conditions are conditions where there is no oxygen present.
• The greater the concentration gradient, the faster the rate of diffusion
• water molecules will move through the membrane in both directions, but the net (overall) movement of water will be from the dilute solution to a concentrated solution.
• Exchange surfaces are surfaces that are adapted to maximise the efficiency of gas and solute (a substance dissolved in a liquid) exchange across them.
• Exchange surfaces have a large surface area
• How does having a large surface area increase the rate of diffusion?

  It allows more of a substance to diffuse at the same time
• Exchange surfaces tend to have a thin membrane