Final answer:
To identify an onion cell undergoing cytokinesis, one should look for the formation of a cell plate at the center of the cell under a microscope. This plate leads to the development of new plasma membranes and a new cell wall, separating the two daughter cells.
Step-by-step explanation:
Understanding Cytokinesis in Onion Cells
If you were to observe an onion cell undergoing cytokinesis, you would notice that after mitosis, the cell begins to divide into two daughter cells. During this final stage of cell division, a structure called a cell plate forms at the center of the cell, which will ultimately lead to the formation of a new cell wall, separating the two cells. Unlike animal cells that use a cleavage furrow to cinch the cell into two parts, plant cells like the onion cells cannot employ this method due to the rigidity of their cell walls. Therefore, the process of cytokinesis in plant cells involves building a new structure down the middle.
By observing onion cells under a microscope, you may identify one in cytokinesis by the presence of a forming cell plate at the cell's equator. As cytokinesis progresses, a new plasma membrane will develop on each side of this plate, and eventually, a new cell wall will complete the separation of the two daughter cells. This process ensures that each new cell has a complete set of genetic material as well as a portion of the cytoplasm and organelles.