Question

One of the fundamental characteristics of cell membrane is:
A. Amino acid regulation.
B. Fat regulation.
C. Glucose regulation.
D. Ion regulation.

Answer 1

The plasma membrane is the coating that protects animal cells from the elements. It is a lipid- and protein-based semi-permeable membrane. Protecting the integrity of the internal cell is one of the key roles of the cell membrane. Providing support and preserving the cell's form. Through the balance of endocytosis and exocytosis, it aids in cell growth regulation.

Complete explanation:
Option A: As a result of the facilitated diffusion, polar and charged molecules including carbohydrates, amino acids, nucleosides, and ions can traverse the plasma membrane. Carrier proteins allow carbohydrates, amino acids, and nucleosides to diffuse more easily through the plasma membranes of most cells.
So, option A is incorrect.
Option B: In animals, including humans, fatty acids form the basis of cell membranes, supply metabolic energy, alter the functioning of membrane-bound enzymes/receptors, conduct signalling cascades, and aid in learning-related memory cognition.
So, option B is incorrect.
Option C: Through $GLUT4$ glucose transporters, insulin promotes glucose absorption into adipose tissue and skeletal muscle. Insulin stimulates the mobilisation of vesicles carrying $GLUT4$ glucose transporters to the plasma membrane, resulting in glucose transfer into the cell.
So, option C is incorrect.
Option D: Special transport proteins in the cell membrane allow just particular ions to flow through. This is necessary for the cell's electrochemical equilibrium with the environment to be maintained.
So, option D is correct.

Hence, Option D) is the correct answer.

Note:
Biological membranes are made up of a bilayer of lipid molecules that form a double sheet. The phospholipid bilayer is the name given to this structure. Membrane proteins and sugars, in addition to the numerous types of lipids found in biological membranes, are also important components of the structure. A cell's plasma membrane, also known as the cell membrane, offers protection. It also maintains a constant environment within the cell, and the membrane serves a variety of purposes. The first is to move nutrients into the cell, and the second is to move harmful chemicals out.