Question

Cell membranes are asymmetrical. Which of the following statements is the most likely explanation for the membrane's asymmetrical nature?

A) Since the cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium, the membrane must be asymmetrical

B) Since cell membranes communicate signals from one organism to another, the cell membranes must be asymmetrical.

C) The two sides of a cell membrane face different environments and carry out different functions.

D) Proteins only function on the cytoplasmic side of the cell membrane, which results in the membrane's asymmetrical nature.

Answer 1

Cell membranes are asymmetrical due to the distinct compositions and roles of the proteins, lipids, and carbohydrates on each side, tailored to the specific environments and functions they face.

Step-by-step explanation:

The asymmetrical nature of cell membranes is most accurately explained by the fact that the two sides of a cell membrane face different environments and carry out different functions, as represented by option C.

Cell membranes are composed of a phospholipid bilayer with embedded proteins that serve different roles on either side of the bilayer. On the interior, some of these proteins anchor the membrane to the cytoskeleton, while on the exterior, proteins might be involved in binding elements of the extracellular matrix. Additionally, carbohydrates attached to proteins or lipids found on the external surface are crucial for cellular recognition and signaling processes. This differentiation in composition and function between the two layers contributes to the cell membrane's asymmetry.