CELL STRUCTURES AND FUNCTION
CELL CYCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Chromosomes attach to mitotic spindles and align along the equator of the cell.
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The cell grows and carries out normal cell processes and DNA replicates.
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Chromosomes reach poles of the cell, nuclear envelope, reforms, nucleolus reappears, and chromosomes decondense.
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Microtubules shorten moving chromosomes to opposite poles.
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Nuclear membrane disintegrates, the nucleolus disappears, chromosomes condense, mitotic spindle begins to form between the poles.
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Detailed explanation-1: -During prophase, the chromosomes condense and the nucleolus disappears. At the beginning of prophase, the chromosomes are condensing to become visible microscopically. Each chromosome consists of two parallelsister chromatids, joined together at one point along their length at thecentromere.
Detailed explanation-2: -During prophase, the chromosomes condense, the nucleolus disappears, and the nuclear envelope breaks down.
Detailed explanation-3: -During prophase, the complex of DNA and proteins contained in the nucleus, known as chromatin, condenses. The chromatin coils and becomes increasingly compact, resulting in the formation of visible chromosomes. Chromosomes are made of a single piece of DNA that is highly organized.
Detailed explanation-4: -The mitotic spindle also begins to develop during prophase. As the cell’s two centrosomes move toward opposite poles, microtubules gradually assemble between them, forming the network that will later pull the duplicated chromosomes apart.
Detailed explanation-5: -At the end of prophase I, the nuclear membrane breaks down, the centrosomes have migrated to the opposite ends of the cell, and the spindle apparatus is being formed. This is followed by metaphase I. During this stage, the spindle fibers, or microtubules, attach to the centromere of each chromosome.