Which one of the following is the best stage to observe the shape, size, and number of chromosomes in a cell?
Metaphase is a stage of mitotic or meiotic cell division in the eukaryote. It comes after the prophase. During the “Growth” phase of the cell cycle or in the resting phase the chromosomes are present inside the nucleus. Each chromosome appears as a thread. Therefore, individual chromosomes are unable to observe in the nucleus.
However, during metaphase, the chromosomes are very much condensed (less condensed than the anaphase stage) and visible inside the cell. During metaphase, chromosomes align in the center of the dividing cell and each chromosome becomes distinguishable from the other. Thus, the best phase to study the chromosome is metaphase. Karyotyping is a procedure used to observe chromosomal abnormalities using metaphasic chromosomes.
The proteins help in the condensation of chromosomes during cell division are “Condensins”. In eukaryotes, condensins are of two types. They are known as condensin I and condensin II.