In which type of cell does a cell plate form during cytokinesis?
a. in plant cells
b. in animal cells
c. in plants and animals
d. in all cells
answer: d
In plant cell
To determine in which type of cell a cell plate forms during cytokinesis, one can first understand the process of cytokinesis. Cytokinesis is the final stage of cell division, where the cytoplasm divides and two daughter cells are formed.
In animal cells, cytokinesis occurs through a process called cleavage furrow formation. During this process, a contractile ring made of actin and myosin filaments forms at the equator of the cell. The contractile ring contracts, causing the cell membrane to pinch inward, eventually leading to the separation of the two daughter cells.
In contrast, plant cells have a different mechanism for cytokinesis. They form a structure known as a cell plate, which develops in the middle of the dividing cell. The cell plate is composed of vesicles containing cell wall material, such as cellulose, which are brought in by the Golgi apparatus. As the vesicles fuse together, the cell plate expands and merges with the pre-existing cell wall, partitioning the cytoplasm between the two daughter cells.
Based on this understanding, we can conclude that the correct answer is a. In plant cells. A cell plate forms during cytokinesis in plant cells, whereas animal cells utilize a cleavage furrow. Therefore, options b and c, in animal cells and in plants and animals respectively, are incorrect. Option d, in all cells, is also incorrect, as cytokinesis in plant and animal cells differs in terms of the structure formed during the process.