Miss Lee - Diffusion

Question 1

What is simple diffusion

Answer 1

Simple diffusion is the net (overall) random movement of particles from a region of high concentration to low concentration (down a concentration gradient). This is due to random movement (kinetic energy) a passive process means no metabolic energy is needed – ATP energy is needed. This continues until the concentration equilibrium between both sides is reached.

Question 2

What is facilitated diffusion

Answer 2

Facilitated diffusion is the passive movement of molecules down a concentration gradient (high to low) across the membrane, and involve special carrier and channel proteins in the membrane.

Question 3

Factors that affect the rate of diffusion

Answer 3

1. The difference in concentration the More particles are in one area compare to another area increases the rate of diffusion this is due to more random frequent collisions of particles happening.
2. The temperature also affects the rate of diffusion is the increased temperature increases the kinetic energy making more frequent collisions between particles and therefore increasing the rate of diffusion as there are more random frequent collisions.
3. The surface area to membrane the larger the surface area the more particles are able to cross the membrane more frequently and therefore the rate of diffusion increases
4. Thickness of the exchange surface/membrane The thing of the membrane walls are the quicker the rate of particles moving across the membrane can happen therefore increases diffusion.

Question 4

Biological examples of diffusion

Answer 4

1. The Aviles have a large surface area to volume ratio as they are very small and high in quantity.
2. The intestines have thin walls making the diffusion pathway quick
3. The synapse the neurotransmitter chemicals defuse over the signups from an area of high concentration to low concentration.
4. A leaf as the estimate to stay open at night and carbon dioxide diffuses through the plan.