Q. The photomicrographs show cells in various stages of the cell cycle. Identify the stage where semi-conservative replication of DNA takes place.

 2083  146 NTA AbhyasNTA Abhyas 2020Cell Cycle and Cell Division Report Error

Solution:

S or synthesis phase marks the period during which DNA synthesis or replication takes place. During this time, the amount of DNA per cell doubles. Prophase is marked by the initiation of condensation of chromosomal material. The chromosomal material becomes untangled during the process of chromatin condensation. The metaphase is characterised by all the chromosomes coming to lie at the equator with one chromatid of each chromosome connected by its kinetochore to spindle fibres. At the onset of anaphase, each chromosome arranged at the metaphase plate is split simultaneously and the two daughter chromatids begin their migration towards the two opposite poles.