Question

a cell possessing 6 chromosomes at the beginning of g1 will have ________ chromosomes, ____ dna molecules, and ________ chromatids during metaphase of mitosis.
o 6; 12; 12
o 12; 24; 24
o 6; 12; 6
o 12; 12; 12

Explanation:

Step1: Understand chromosome behavior in mitosis

In G1, a cell has its normal chromosome number. During S - phase, DNA replicates. By metaphase of mitosis, the DNA has replicated but the sister chromatids are still attached at the centromere.

Step2: Determine chromosome number

The chromosome number remains the same from G1 to metaphase of mitosis in somatic cell division (mitosis). If there are 6 chromosomes at the beginning of G1, there will be 6 chromosomes at metaphase of mitosis.

Step3: Determine DNA molecule number

Since DNA replicates during S - phase, if there are originally 6 chromosomes (each with 1 DNA molecule in G1), after replication there are 12 DNA molecules (as each chromosome now consists of two sister chromatids, each with 1 DNA molecule).

Step4: Determine chromatid number

Each replicated chromosome consists of two sister chromatids. With 6 replicated chromosomes at metaphase of mitosis, there are 12 chromatids.

Answer:

6; 12; 12