Question

Middle lamella is mainly composed of
A) Hemicellulose
B) Calcium pectate
C) Muramic acid
D) Phophoglyceride

Answer 1

Hint: Middle lamella is the cementing layer between the primary walls of the adjacent cells. The cell plate formed during cell division develops into middle lamella. In mature plants, it is the outermost layer of the cell wall.

Complete Answer:
- Middle lamella is the layer which bridges the cell wall of the two adjoining cells. The two cells are glued together by a pectin rich polysaccharide.
- In matured plants, the pectins form a continuous layer between the adjacent cells. It is mainly composed of calcium pectate or magnesium pectate.
- Middle lamella helps in maintaining the structural integrity of the cell. It also prevents the cell from sliding upon each other.
1) Hemicellulose: It is the chief constituent of the cell wall of plants.
2) Muramic acid: It is the building material of the cell wall of bacteria.
3) Phosphoglyceride: It is the main component of the membrane of the organelles, like E.R, cell membrane, nuclear membrane.

Thus the correct answer is B. Middle lamella is made up of calcium pectate.

Additional information: The pectins have a gel like structure and properties. Thus they are used as gelling agents in the food.

Note: Middle lamella is obtained from the cell plate during the cell division. It is composed of pectins of calcium or magnesium. It acts as a shock absorber. It absorbs mechanical stress.