National League for Nursing (NLN PAX) Practice Exam

What major difference exists between nuclear cell division in plants compared to mammals?

1. Homologous chromosomes are paired

2. Centrioles are replicated

3. Spindle fibers are missing

4. Cell plates are synthesized

The correct answer is: Cell plates are synthesized

In plant cell division, particularly during cytokinesis, a key distinction is the formation of a cell plate, which is synthesized to separate the two daughter cells. During telophase, vesicles containing cell wall materials gather in the center of the cell, eventually fusing to create the cell plate. This plate expands outward until it fuses with the existing cell wall, establishing two separate cells. In contrast, mammalian cells undergo a cleavage furrow process to achieve cytoplasmic division. The mechanisms used by plants to transform from a single cell into two distinct daughter cells involve unique structures and processes not found in animal cells, emphasizing the importance of the cell plate in plant division. Other choices do not capture the essential differences in cell division processes. Homologous chromosome pairing is common to both plant and mammalian cells during the early stages of meiosis, and centrioles, which are part of the cell's microtubule organizing centers, are present in animal cells and not functionally replicated in the same way in plants. Similarly, spindle fibers are present in both types of cells during the mitotic phase to ensure accurate chromosome separation. Hence, the synthesis of cell plates is what distinctly characterizes nuclear cell division in plants compared to mammals.