Asked • 08/02/19

Chromosome and chromatid numbers during cell cycle phases?

A diploid cell in G1 has 6 chromosomes. How many chromosomes and how many chromatids are present in each of the following stages?Here is what I am guessing- G1: 6 chromosomes ; 6 chromatids \n\n- G2: 6 chromosomes ; 12 chromatids \n\n- Prophase: 6 chromosomes; 12 chromatids \n\n- Metaphase: 6 chromosomes; 12 chromatids \n\n- Anaphase: 12 chromosomes; 12 chromatids \n\n- Telophase: 12 chromosomes; 12 chromatids

Sorita D.

During the later stages of cell division these chromatids separate longitudinally to become individual chromosomes. Chromatid pairs are normally genetically identical, and said to be homozygous; however, if mutation(s) occur, they will present slight differences, in which case they are heterozygous.First, during the S phase of interphase, the genetic material of a cell is duplicated. A human has 46 chromosomes (a set of 23 you inherit from your mother, and a set of 23 from your father). After the genetic material is duplicated and condenses during prophase of mitosis, there are still only 46 chromosomes – however, they exist in a structure that looks like an X shape:During prophase and metaphase of mitosis, each chromosome exists in the above state. For humans, this means that during prophase and metaphase of mitosis, a human will have 46 chromosomes, but 92 chromatids (again, remember that there are 92 chromatids because the original 46 chromosomes were duplicated during S phase of interphase). It is helpful to see this visualized (for visual simplicity, a 2n=8 arrangement of chromosomes will be demonstrated, rather than the 2n=46 arrangement of chromosomes in humansthere are 8 chromosomes present, but 16 chromatids. Similarly, in humans (2n=46), there are 46 chromosomes present during metaphase, but 92 chromatids.It is only when sister chromatids separate – a step signaling that anaphase has begun – that each chromatid is considered a separate, individual chromosome. Pictured below, we see how the 2n=8 cell from above has progressed from having 8 chromosomes to 16 chromosomes: During anaphase, we now have a total of 16 chromosomes and 16 chromatids – in short, each chromatid is now a chromosome. Similarly, in humans, there are 92 chromosomes present and 92 chromatids during anaphase. These numbers remain the same during telophase. It is only after the end of mitosis – when the dividing cells have fully separated and the membranes have reformed
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08/04/19

1 Expert Answer

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Bodhi V. answered • 08/09/19

Effective Biology, Anatomy, and Physiology Teacher

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