Question

Compare the chromosomes in a cell at metaphase of mitosis with those in a cell at metaphase II. (See Figures 12.7 and 13.8.).

Short answer

Metaphase of meiosis is different from mitosis. The difference is only observed at metaphase-I. Metaphase-II appears similar to the metaphase of mitosis.

There is only a single plate where chromosomes lie at the equator in metaphase -II and the metaphase of mitosis. Both the metaphases (metaphase I and metaphase of mitosis) are the same.

Step-by-step solution

Chromosomes location in the cell

The chromosomes are located inside the nuclear membrane or the nucleus in eukaryotes, while in prokaryotes, it is located in the cell only as there is no nuclear membrane. Chromosomes are long thread-like structures that can be found inside the nucleus in human cells.

Variations in chromosomes number in metaphase of mitosis and meiosis I

The chromosome numbers vary in mitosis and meiosis I because crossing over does not occur in mitosis, and there are no paternal and maternal chromosomes. The chromosomes are from a single cell. It can be seen in bacterial cells or autosomal cells.

Therefore, in mitosis, only one equatorial plate is formed, and in meiosis, two kinds of chromosomes are involved that is mother as well as from father side. So, two equatorial plates are formed, one of the chromosomes of the mother chromosome and the other from the father chromosomes.

Metaphase of meiosis II and mitosis

The metaphase is characterized by bringing the chromosomes to the metaphasic plate. The spindle formation completes in this phase—the microtubules found in the spindle fiber help in the movement of the chromosomes.

In the case of mitosis, on the equatorial plate, chromosomes appear as two threaded, while in the case of meiosis (metaphase I), chromosomes appear as one threaded. Metaphase II is the same as mitosis's metaphase.