CELL DIVISION
CELL DIVISION AND CANCEROUS CELLS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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DNA synthesis occurs
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The DNA in the nucleus is replicated
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Each chromosome multiplies into two identical chromosomes known as sister chromatids. Both chromatids contain the same copy of the DNA molecule.
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Both chromatids are joined at thecentromeres.
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stage, the nucleus looks big
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Detailed explanation-1: -In the S phase (synthesis phase), DNA replication results in the formation of two identical copies of each chromosome-sister chromatids-that are firmly attached at the centromere region. At this stage, each chromosome is made of two sister chromatids and is a duplicated chromosome.
Detailed explanation-2: -During DNA duplication in the S phase, each chromosome is replicated to produce two identical copies, called sister chromatids, that are held together at the centromere by cohesin proteins. Cohesin holds the chromatids together until anaphase II.
Detailed explanation-3: -Centromere Identity Is Preserved During Cell Division During the S phase that follows mitotic division, the presence of CENP-A nucleosomes marks the position of the centromere on the two daughter DNA strands.
Detailed explanation-4: -The two “sister” chromatids are joined at a constricted region of the chromosome called the centromere. During cell division, spindle fibers attach to the centromere and pull each of the sister chromatids to opposite sides of the cell. Soon after, the cell divides in two, resulting in daughter cells with identical DNA.
Detailed explanation-5: -During S phase, each chromosome is replicated. This produces a second copy of each chromosome from the mother and a second copy of each chromosome from the father. These identical copies are known as sister chromatids. These sister chromatids are held together by the centromere.