Question

The phospholipid bilayer is made up of:
A. Sugars and phosphoproteins
B. Proteins and phospholipids
C. Phosphoproteins and lipids
D. DNA and carbohydrates
E. PhosphoDNA and lipids

Answer 1

Hint:- Plasma membrane is the outer layer of the cell. It is composed of a bilayer of phospholipids and proteins with phosphate groups on the surface and lipids embedded in the membrane. The proteins are interspersed in the membrane like a mosaic.

Complete step-by-step solution:-
The most accepted model of phospholipid bilayer is fluid mosaic model, according to this model, the plasma membrane is a mosaic of components primarily phospholipids and proteins however it has some other components also such as cholesterol and carbohydrates.
The principal components of the plasma membrane are lipids and proteins.
Phospholipids: It is a lipid made up of glycerol, two fatty acid tails and a phosphate linked head group. Biological membranes usually involve two layers of phospholipids, with their tails pointing inward, an arrangement called a phospholipid bilayer. They are well suited for the role of basic fibre of the plasma membrane because they are amphipathic meaning that they have both hydrophilic and hydrophobic regions.
Proteins: Proteins are the second major component of the plasma membrane. They are of two types: integral protein (integrated inside the membrane) and peripheral protein (found outside and inside surfaces of the membrane).
So, the correct answer is option C.

Note:- The proportions of proteins, lipids and other components in the plasma membrane vary between different types of cells. For a typical human cell, however, proteins account for about 50% of the composition by mass and lipids account for about 40% of the composition by mass and the remaining 10% comes from carbohydrates.