Question

Syncytium formation takes place if
a. Cytokinesis is not followed by karyokinesis
b. Karyokinesis does not occur
c. Karyokinesis is not followed by cytokinesis
d. Both karyokinesis and cytokinesis are prevented

Answer 1

Hint: A syncytium, also called a symplasm, is a multinucleate cell (having more than one nucleus in a cell). This condition is reached when multiple mononuclear cells (many cells having one nucleus) fuse together. Syncytium can also be defined as formation of a giant cell produced by fusion of two or more cells.

Complete answer:
In mitosis, there is not only the duplication of chromosomes that take place, but also the cell is divided into two daughter cells. This process of division of cells into two daughter cells is known as cytokinesis. The nucleus of the cell also divides equally in the two daughter cells, and the process is called karyokinesis.

Sometimes, karyokinesis is not followed by cytokinesis, due to which multinucleate condition occurs that leads to formation of syncytium.
So, the correct option is (C) Karyokinesis is not followed by cytokinesis.

Cytokinesis is a process of cell division in which the parental cell divides into two daughter cells. It occurs in both mitosis and meiosis. As a result, each daughter nuclei produced has a separate nucleus. Cytokinesis starts at anaphase and continues upto telophase.

Syncytium formation occurs in two ways, either when the nucleus of a cell divides but does not split into multiple cells; or when multiple cells join together retaining their nuclei but their cell membranes do not remain separated and merge together forming a giant cell. An example of syncytium is liquid endosperm in the coconut.

Note: In contrast to syncytium, coenocyte is formed when the nucleus divides several times without being associated with cytokinesis. This results in the formation of cells connected by specialized membranes, for example heart muscle cells.