Refer to the table below. Which substances in the table can be predicted to pass, via simple diffusion, across a biological membrane?
A) 2, 3, 5
B) 2, 3, 4, 7
C) 2, 3, 5, 7
D) 1, 2, 3, 5, 6
E) 2, 3, 4, 5, 6, 7

Question

Refer to the table below.  Which substances in the table can be predicted to pass, via simple diffusion, across a biological membrane?
A) 2, 3, 5 
B) 2, 3, 4, 7 
C) 2, 3, 5, 7 
D) 1, 2, 3, 5, 6 
E) 2, 3, 4, 5, 6, 7

Quizplus · Accepted Answer

Substances that can be predicted to pass via simple diffusion are those that are small in size, nonpolar or lipid-soluble, and have a concentration gradient across the membrane. Based on the given information, molecules 2, 3, and 7 meet these criteria and can therefore pass via simple diffusion. Molecule 5 is also small in size and nonpolar, but its charge would prevent it from passing easily, although it still could pass via facilitated diffusion. Molecules 1 and 6 are too large to pass via simple diffusion, and molecule 4 is polar and thus would not pass easily either. Therefore, the correct answer is C.

Refer to the Table Below