In: Anatomy and Physiology
1.
A) Fill in the blanks: Faciliated diffusion requires a _____________________ for a solute to be transported down its concentration gradient. This is due to __________ or _________________ limitations
B) How do transport proteins become saturated? How does this affect the rate of facilitated diffusion?
A. Faciliated diffusion requires a carrier protein for a solute to be transported down it's concentration gradient. This is due to large molecules or ions not cross the cell membrane limitations.
In faciliated diffusion small molecules cross the cell membrane easily but large molecules and charged ions are not cross the cell membrane they need a carrier. Facilitated diffusion does not require energy they move the molecules or ions depend on specific proteins. Also called passive transport. Ex glucose, sodium ions and potassium ions.
B. The rate of diffusion affected by properties of cell, diffusing molecule and surrounding solution. Passive transport solute into a cell is linerly related to the concentration of solute outside of the cell. Carrier proteins increase the rate of diffusion by increase the more solute enter into cell. When protein saturated the faciliated diffusion rate is maximum. Facilitated diffusion can increase the rate of diffusion with increasing solute concentration and additional increases in external solute concentration but cannot increase the rate of diffusion when once protein saturated.