Chromosome and chromatid numbers during cell cycle phases?

Question

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

Answer 1

You are correct in all of your guesses. The confusing part is that what constitutes a chromosome is different at different times in the cell cycle, depending upon whether the DNA has replicated or not, and when the sister chromatids separate, changing a chromosome from containing 2 chromatids to only 1.

So G1 1 Chromosome = 1 Chromatid

S is DNA replication so 1 Chromosome = 2 chromatids

G2, Prophase, and Metaphase: 1 Chromosome = 2 chromatids

Anaphase and Telopphase: 1 Chromosome = 1 chromatid