Question

why do plants cells have an additional layer surrounding the cell membrane? what is this layer known as?

Answer 1

Answer:

The layer surrounding the cell membrane in a plant cell is known as Cell Wall.

Explanation:

• In plant cells,the cell wall  is constituted of polysaccharides which includes cellulose, hemicellulose and pectin.
• Unlike the cell membrane which is selectively permeable, the cell wall is semi-permeable in nature.
• The major function of the cell wall is to provide the following to the plant cell:

1. high tensile strength so that it can withstand alternation in internal osmotic pressure,
2. flexibility for partial movement,
3. protection,
4. definite shape to the cell.

Answer 2

The additional layer surrounding the cell membrane is cell wall

Explanation:

Cell Wall-

• It is a semi permeable membrane that is present in the plant and the main component of the the cell wall is cellulose.
• Plant cell contain 3 layers which are called- Middle lamella, Primary cell wall and secondary cell.
• Middle lamella is the outer most layer containing pectins. Then the primary cell wall is formed between middle lamella and plasma membrane containing hemi cellulose. Between the primary cell wall and middle lamella, secondary cell wall forms .
• The additional layers provide rigidity, protection,support,and also regulate the growth and diffusion of substance into the cell, storing the foods.