Question

Cell membrane is composed of which of the following components?
A. Proteins and Cellulose.
B. Proteins and Phospholipids.
C. Proteins and Carbohydrates.
D. Proteins, Phospholipids, some carbohydrates.

Answer 1

Hint: Cell membrane or plasma membrane is the outermost membrane present in animal cells whereas, Plant cell consists of cell wall as well as plasma membrane.
It is a selectively permeable membrane.
Nageli and Cramer coined the term cell membrane in 1855.

Complete answer: In order to solve this question, we need to know about cells and their components.
Cell is a basic unit of life.
All the organisms are composed of cells
Some organisms are made up of single cells are known as unicellular organisms, while other organisms like human beings are made up of many cells, are known as multicellular organisms.
Cell consists of three parts:
1. Cell membrane
a. Outer membrane- cell wall
b. Inner membrane- cell membrane
2. Nucleus
3. Cytoplasm
But, the animal cell lacks the outer membrane known as a cell wall.
So, that’s why plasma membrane is the only one outer covering/membrane which protects the cell or inside of the cell from the outer environment.
Cell membrane is composed of lipid bilayer. Lipids are arranged in such a way that the polar head faces towards the outer part and the hydrophobic tail towards the inner part.
Cell membrane also contains the proteins and carbohydrates.
Proteins are classified as integral (intrinsic) proteins and peripheral (extrinsic) proteins.
Integral protein lies on the surface of the layer whereas; peripheral protein is totally buried in the layer.
Carbohydrates help in the cell recognition and adhesion.
It also acts as a physical barrier.

So, the correct answer is proteins, carbohydrates, phospholipids.

Note: Prokaryotic cells: cells that lack a membrane bound organelle (nucleus).
Eukaryotic cells: cells which contain the membrane bound organelle (nucleus).