Diffusion

Question 1

What is diffusion

Answer 1

Net movement of particles from an area of high concentration to an area of low concentration

Question 2

How much energy is needed for diffusion

Answer 2

None, it’s a passive process

Question 3

Factors effecting the rate of diffusion

Answer 3

•The concentration gradient- the higher it is, the faster the rate of diffusion
•The thickness of the exchange surface- the thinner the exchange surface, the faster the rate of diffusion
•The surface area- the larger the surface area, the faster the rate of diffusion

Question 4

Define simple diffusion

Answer 4

• Passive process requires no energy from ATP hydrolysis.
• Net movement of small, lipid-soluble molecules directly through the bilayer from an area of high concentration to an area of lower concentration (i.e. down a concentration gradient).

Question 5

Define facilitated diffusion

Answer 5

Passive process
Specific channel or carrier proteins with complementary binding sites transport large and/ or polar molecules/ ions (not soluble in hydrophobic phospholipid tail) down concentration gradient

Question 6

Factors that effect facilitated diffusion

Answer 6

•The concentration gradient-the higher the concentration gradient the faster the rate of facilitation diffusion. As equilibrium is reached, the rate of diffusion will level off
•The number of channel and carrier protiens- once all the proteins in the membrane are used, facilitated diffusion can’t happen any faster, even if you increase the concentration gradient

Question 7

How does a carrier protein work

Answer 7

•First, a large molecules attached to a carrier protein in the membrane
•Then, the protein changes shape
•This released the molecule in the opposite side of the membrane

Question 8

How do channel proteins work

Answer 8

Form pores in the membrane for charged particles to diffuse through (down their concentration gradient)