In the process of dialysis, a special semipermeable membrane allows both small molecules and water to pass through, but not large protein molecules. These membranes are used to separate these small molecules and ions from much larger proteins. If a mixture of proteins and small molecules were separated from pure water by a dialysis membrane as shown in the figure, which way would the molecules flow?
A) Both water and small molecules would pass through into the pure water.
B) Only the proteins would pass through into the pure water.
C) Water would enter the solution while small molecules would pass through into the pure water.
D) Only small molecules would pass through the membrane; water and proteins would not.
E) Only water would pass through the membrane into the solution.

Question

In the process of dialysis, a special semipermeable membrane allows both small molecules and water to pass through, but not large protein molecules. These membranes are used to separate these small molecules and ions from much larger proteins. If a mixture of proteins and small molecules were separated from pure water by a dialysis membrane as shown in the figure, which way would the molecules flow? 
A) Both water and small molecules would pass through into the pure water. 
B) Only the proteins would pass through into the pure water. 
C) Water would enter the solution while small molecules would pass through into the pure water. 
D) Only small molecules would pass through the membrane; water and proteins would not. 
E) Only water would pass through the membrane into the solution.

Quizplus · Accepted Answer

In dialysis, smaller molecules and water can pass through the semipermeable membrane, but larger proteins cannot. Therefore, in this scenario, water will enter the solution to equalize the concentrations and small molecules will pass through the membrane, but proteins will not be able to pass through. This will result in the solution becoming more dilute, with a lower concentration of small molecules and a higher concentration of water.

In the Process of Dialysis, a Special Semipermeable Membrane Allows