Question

Choose the best answer that makes the sentence correct. A membrane that allows only some materials to move in and out of the cell is _____.

A. permeable

B. semipermeable

C. rigid

D. bilayered

Answer 1

A membrane that allows only some materials to move in and out of the cell is B. Semipermeable.

Answer 2

B. semipermeable

The membrane is selectively permeable because substances do not cross it indiscriminately. Some molecules, such as hydrocarbons and oxygen can cross the membrane. Many large molecules (such as glucose and other sugars) cannot. Water can pass through between the lipids.