The cytoplasm of an animal cell is divided by means of:
a. A cleavage furrow.
b. A cell plate.
c. A cell membrane formed within the cytoplasm.
d. Mitosis
The correct answer and explanation is:
The correct answer is a. A cleavage furrow.
Explanation:
In animal cells, the process of cytoplasmic division is called cytokinesis. During cytokinesis, the cell’s cytoplasm is divided to form two distinct daughter cells. In animal cells, this division occurs through the formation of a cleavage furrow. The cleavage furrow is a pinching or constriction that develops around the middle of the cell, eventually dividing the cytoplasm into two equal parts.
The formation of the cleavage furrow is a result of the action of a structure called the contractile ring, composed mainly of actin filaments. These actin filaments contract, pulling the membrane tighter and tighter at the center of the cell. As this contraction continues, the cleavage furrow deepens until the cell is pinched in two, creating two daughter cells.
This process contrasts with cytokinesis in plant cells, where a cell plate forms instead of a cleavage furrow. The cell plate is a structure that develops at the center of the plant cell, composed of vesicles filled with cell wall materials. These vesicles fuse to form the cell plate, which gradually enlarges and eventually fuses with the cell membrane, dividing the plant cell into two.
Mitosis, on the other hand, is the process of nuclear division that ensures the equal distribution of genetic material into two daughter cells. While mitosis is essential for cell division, the actual division of the cytoplasm occurs during cytokinesis. The cell membrane formed within the cytoplasm is not responsible for dividing the cytoplasm but is involved in enclosing the cell contents.
Therefore, the cleavage furrow is the primary structure that divides the cytoplasm in animal cells during cytokinesis.