Question

ASAP please i need help!

At what phase of mitosis does the number of chromosomes double?


At what phase of mitosis does the amount of genetic material in each chromosome become half of what it just was?
During what process in the cell cycle does one cell become two cells?

Answer 1

you might post this in the biology subject. :D

Answer 2

I can answer the first one

Answer 3

Let´s start by saying that chromosome do NOT doubled in MITOSIS but in S-phase (S for "synthesis"), in which each DNA molecule (i.e. chromosome) is duplicated by a very precise mechanism. By this, it is meant that the DNA molecule strand is copied exactly by the DNA polymerase. The histone proteins, as well as the proteins that compose the kinetochore, are "replicated" (well, better say synthesized) after S-phase, during G2. The way that the DNA polymerase ensure that the new DNA molecules are identical to the "parental" ones is through DNA nucleotide pairing. This is to say, that the polymerase will always pair a T with A and a G with C, therefore the enzyme can exactly predict what the sequence of the new strand should be, based on the "old" one. After this, mechanisms of repair and proof-reading make sure that the polymerase had not make any mistakes, or changes the mismatching nucleotides.

What happen during mitosis, is that the 2 sister chromatides that compose the chromosome after this having being replicated are separated, and each ends up in a daughter cell. Which will have identical genetic material to the parental cell.