Question

A plasma membrane and a cell wall _____.

A) are two names for the same thing
B) have the same structure and different functions
C) have different structures
D) have different structures and different functions

Answer 1

Have different structures and different functions.

Answer 2

D) have different structures and different functions

Step-by-step explanation:

Plasma membrane and cell wall both are parts of a cell however they have different structures and serve different functions.

Plasma membrane

Structure:

It is primarily made up of a continuous phospholipid bilayer which surrounds the cell and other organelles. Apart from this bilayer, it also contains some other components like integral & peripheral proteins, glycolipids, cholesterol, carbohydrates which are either embedded or attached to this phospholipid bilayer.

Functions:

1) It maintains integrity of cell;

2) It helps the cell to interact with external environment;

3) It is selectively permeable, so it allows only useful substances to come inside cell and allows the exit of only selective substances from cell;

4) Plays very important role in cellular signaling which is responsible for various cellular responses based on the ligand/signal;

5) It helps in cell to cell attachment.

Cell wall

Structure:

In plants, cell wall is primarily made up of cellulose which is a very hard structure. Apart from this, it also comprises hemicellulose, pectin and lignin. In fungi, it is made up of chitin while in bacteria it is made up of peptidoglycan.

Functions:

1) It surrounds the entire cell membrane and provides structural support to the cell;

2) It also provides protection to the cell.