CELL STRUCTURES AND FUNCTION
CELL DIVISION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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23 chromosomes, 23 chromatids Before46 chromosomes, 46 chromatids After
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46 chromosomes, 46 chromatids Before92 chromosomes, 92 chromatids After
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23 chromosomes, 23 chromatids Before23 chromosomes, 46 chromatids After
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46 chromosomes, 46 chromatids Before46 chromosomes, 92 chromatids After
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Detailed explanation-1: -During the S phase, the DNA molecules undergo replicatiomn to create a copy of their DNA. However, the number of chromosomes remains same. So, 46 chromosomes will be present after S phase in a human.
Detailed explanation-2: -Chromosomes come in pairs. Normally, each cell in the human body has 23 pairs of chromosomes (46 total chromosomes). Half come from the mother; the other half come from the father.
Detailed explanation-3: -Prophase: During prophase, the nuclear envelope of the cell (which is where the 92 sister chromatids are contained) begins to break down. The centrioles, which are only present in animal cells, separate and each moves to an opposite end of the cell.
Detailed explanation-4: -S phase (DNA Synthesis)-Each of the 46 chromosomes are duplicated by the cell. III.
Detailed explanation-5: -During S phase, which follows G1 phase, all of the chromosomes are replicated. Following replication, each chromosome now consists of two sister chromatids (see figure below).