Question

35. Which statement best describes the cell membrane of a living plant cell?

A. It selectively regulates the passage of substances into and out of the cell.
B. It is composed of protein and carbohydrates only.
C. It has the same permeability to all substances found inside or outside the cell.
D. It is a double protein layer with floating lipid molecules.

Answer 1

The cell membrane of a living plant cell selectively regulates the passage of substances into and out of the cell (option A).

Step-by-step explanation:

The plasma membrane in a living plant cell is composed of a double lipid layer that gives it hydrophobic character and acts as a semi-permeable barrier. The partial permeability of the substances allows regulating the passage of substances from and to the interior of the cell.

At the level of the plasma membrane there are several mechanisms and transport to allow the entry of substances needed for the cell or the output of synthesized products or metabolic waste, thus regulating the passage of substance in a selective way.

Regarding the other options:

B. Plasma membranes are composed of lipids, not just carbohydrates and proteins.

C. Permeability is not for all substances, but is selective.

D. Plasma membrane is a lipid bilayer, not a double layer of proteins.