Question

Which of the following controls permeability?
A)Cell membrane
B)Cell wall
C)Protoplasm
D)Cytoplasm

Answer 1

Hint: Permeability is the degree of molecules' passive diffusion across the membrane. Such molecules are referred to as permeant molecules. Permeability is primarily dependent on the molecule's electrical charge and polarity and, to a lesser degree, on the molecule's molar mass.

Complete answer:
The cell wall of plants is dead at maturity and, thus, is completely permeable. The cell membrane is, therefore, alive and is semi-permeable biochemically. The cell membrane makes it possible for the solvent to pass in, but only selective solutes can enter or travel out. Consequently, the plasma membrane is selectively permeable or semi-permeable.

According to the model for the fluid mosaic suggested by S. G. Hey, and J. Singer. It is possible to accept biological membranes as a two-dimensional liquid in which lipid and protein molecules disperse more or less quickly, replacing the earlier definition of Davson and Danielli, L. Nicolson Nicolson (1972). Although the lipid bilayers that form the base of the membranes simply form two-dimensional liquids, the plasma membrane also contains a large number of proteins, creating additional structure. Protein-protein complexes, pickets and fences formed by the actin-based cytoskeleton and, probably, lipid rafts are examples of such structures.

Hence, the correct answer is option (A)

Note: Through the self-assembly process, lipid bilayers form. The cell membrane consists predominantly of a thin layer of amphipathic phospholipids that naturally arrange to separate the hydrophobic "tail" regions from the surrounding water while the hydrophilic "head" regions associated with the resulting bilayer's intracellular (cytosolic) and extracellular faces.