NP, thanks for cooperating, here are some more answers:
2. A. Explain the term “concentration gradient”. Make sure to discuss the difference between a
solution's concentration and a concentration gradient.
B. An artificial cell contains 0.03 M sucrose and 0.02 M glucose. It is placed into a solution
containing 0.01 M concentrations each of sucrose, glucose, and fructose. The ‘cell’
membrane is permeable to glucose and fructose, but not sucrose.
1. For which solutes do concentration gradients exist?
2. Which solute(s) will exhibit net diffusion into the cell?
3. Which solute(s) will exhibit net diffusion out of the cell?
A) -Concentration gradient is a change/ difference in the concentration of solutes in a solution between two regions. A gradient results from unequal distribution of ions or molecules across a membrane.
-A solution concentration is the concentration of that solution only, where as a concentration gradient is difference with respect to substances across two regions.
B) It is given that an artificial cell consists of 0.03M sucrose and 0.02 M glucose. The cell is placed in a solution containing 0.01M concentrations each of sucrose, glucose and fructose.
The cell is impermeable to the sucrose, but allows glucose and fructose.
1. Concentration gradient exists only for sucrose, as cell s impermeable for it. The inner concentration is 0.03M and outer is 0.01M. This exerts a concentration gradient of 0.02M across the membrane with respect to the sucrose. Where as the fructose and glucode will move across the membrane until the concentrations are equal on both sides.
2. Net diffusion into the cell is absent. Because the concentrations are higher inside the cell.
3. Glucose will exert net diffusion out of the cell because the concentration outside is low compared to the inside.