Question

The middle lamella is composed of
(a)Pectates
(b)Cellulose
(c)Lignin
(d)Proteins

Answer 1

Hint: The middle lamella may be a layer which cements the cell walls of two adjoining plant cells together. It's the primary formed layer which is deposited at the time of cytokinesis. The cell plate that's formed during cellular division itself develops into middle lamella or lamellum.

Complete answer:
A plant cell is characterised by a cellulosic cell wall. The cell walls are separated by a middle layer or middle lamella. The middle lamella is a cementing layer between two plant cells. It is absent on the outer surface. Middle lamella is made up of calcium and magnesium salts of pectin. Pectins are mucopolysaccharides that occur in plant cell walls. Pectic acid is a polymer of D-galacturonic acid.


Additional Information: -The middle lamella is a cementing layer between the first walls of adjacent cells. The first wall is that the cellulose-containing layer laid down by cells that are dividing and growing.
-While a Tonoplast is a membrane separating a vacuole from the surrounding cytoplasm in a plant cell.
- Frequently, it's difficult to differentiate the centre lamella from the first wall, especially in cells that develop thick secondary walls. In such cases, the 2 adjacent primary walls and therefore the middle lamella, and maybe the primary layer of the secondary wall of every cell, could also be called a compound middle lamella. When the centre lamella is degraded by enzymes, as happens during fruit ripening, the adjacent cells will separate.

So, the correct answer is, “pectates”.

Note: In a multicellular organism, adjacent cells are cemented together by a matrix or a middle lamella which is formed from calcium and magnesium pectate (In real sense middle lamella is nothing but itself a primary cell wall). Animal cells lack a cell wall. Hence, animals lack the middle lamella.