Question

Assertion (A) In animal cells, cytokinesis is achieved by the appearance of a furrow in plasma membrane.
Reason (R) In plant cells, the formation of the new cell wall begins with the formation of simple precursor called cell plate.

• A. If both A and R are true and R is the correct explanation of A.
• B. If both A and R are true, but R is not the correct explanation of A.
• C. If A is true, but R is false.
• D. If A is false, but R is true

Answer 1

Answer: (B)

Both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
In an animal cell, cytokinesis is achieved by the appearance of a furrow in the plasma membrane. The furrow gradually deepens and ultimately joins in the centre thus, dividing the cell cytoplasm into two. This mode of cytokinesis is called cell-furrow method.
Plants cells however, are enclosed by a relatively inextensible cell wall, therefore they undergo cytokinesis by a different mechanism. The formation of the new cell wall begins with the formation of a simple precursor called the cell plate. It represents the middle lamella between the walls of two adjacent cells. This mode of cytokinesis is called cell plate method.