Question

Middle lamella is composed mainly of:
A. Phosphoglycerides
B. Hemicellulose
C. Muramic acid
D. Calcium pectate

Answer 1

Hint: A layer that cements the cell walls of two neighbouring plant cells together is the middle lamella. It is the first layer formed that is deposited at the moment of cytokinesis. During cell division itself, the cell plate that is developed grows into a middle lamella or lamellum. The middle lamella consists of calcium and magnesium pectate. It is the outermost layer of the cell wall in a mature plant cell.

Complete answer:
The middle lamella consists predominantly of Calcium Pectate. The middle lamella is a layer of pectin that cements together the cell walls of two adjoining cells. To give them stability, plants need this and so they can form plasmodesmata between the cells. It is the first layer formed that is deposited at the moment of cytokinesis. During cell division itself, the cell plate that is developed grows into a middle lamella or lamellum. Calcium and magnesium pectates form the middle lamella.
The middle lamella is a layer of pectin that cements together the cell walls of two adjoining plant cells. It is the first layer formed that is deposited at the moment of cytokinesis. During cell division itself, the cell plate that is developed grows into a middle lamella or lamellum. Pectins form a single and continuous layer between neighbouring cells in plants. The middle lamella is often difficult to distinguish from the primary wall, particularly in cells that grow thick secondary walls. Calcium and magnesium pectates form the middle lamella.

Additional Information: Pectins form a single and continuous layer between neighbouring cells in plants. Sometimes, the middle lamella is difficult to distinguish from the primary wall, especially in cells that build thick secondary walls. In such instances, a compound middle lamella can be called the two neighbouring primary walls and the middle lamella, and maybe the first layer of each cell's secondary wall. The neighbouring cells can divide when the middle lamella is degraded by enzymes, as occurs during fruit ripening.
So, the correct answer is ‘calcium pectate’.

Note: The growth of the middle lamella is primarily centripetal, that is, from the edges to the interior, where the cell plate started to develop, it will develop. The layer of the cell wall that is shared by the two daughter cells is the middle lamella, and both contribute to its formation.