CELL STRUCTURES AND FUNCTION
CELL STRUCTURE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Cytokinesis
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Prophase II
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Nondisjunction
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Crossing-over
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Detailed explanation-1: -During meiosis, homologous chromosomes (1 from each parent) pair along their lengths. The chromosomes cross over at points called chiasma. At each chiasma, the chromosomes break and rejoin, trading some of their genes. This recombination results in genetic variation.
Detailed explanation-2: -Crossing over occurs only during prophase I. The complex that temporarily forms between homologous chromosomes is only present in prophase I, making this the only opportunity the cell has to move DNA segments between the homologous pair.
Detailed explanation-3: -During prophase of meiosis I, the double-chromatid homologous pairs of chromosomes cross over with each other and often exchange chromosome segments. This recombination creates genetic diversity by allowing genes from each parent to intermix, resulting in chromosomes with a different genetic complement.