Question 6: The following events occur during the various phases of the cell cycle, Name the phase against each of the events.
a. Disintegration of nuclear membrane _________________________
b. Appearance of nucleolus _________________________
c. Division of centromere _________________________
d. Replication of DNA _________________________
Answer:
a. Prophase
The nuclear envelope breaks down fully before the metaphase, releasing the chromosomes and the other nuclear contents into the cytoplasm.
b. Telophase
This phase lasts for an hour. In this nuclear envelope appears around the each group of chromosomes by coming together and fusion of small vesicles formed in prophase by the breakdown of parent cell’s nuclear envelope and further process goes on. Or we can say that in this phase nucleus is reconstructed from each group of chromosomes.
c. Anaphase
At this phase, two sister chromatids of each chromosome separate from their respective mates and begin to move toward the opposite poles.
d. S- phase
e. DNA synthesis takes place at the S- phase or synthesis phase. Interphase involves the S- phase in which replication of each chromosome occurs by the synthesis of a new DNA molecule on the template of the existing DNA.
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