Homework SourseA 92 DNA molecules per cell Found as 92 separate chromosomes
A. 92 DNA molecules per cell. Found as 92 separate chromosomes. 46 DNA molecules per cell. Found as 46 physically separate chromosomes in each of two nuclei.
B. 92 molecules, 46 chromosomes each with two chromatids attached at centromere. 92 molecules, 46 chromosomes each with two chromatids
C. 46 molecule, 23 chromosomes each with two chromatids attached at centromere. 46 molecules, 23 chromosomes each with two chromatids.
D. 23 molecules, 23 chromosomes in each of two nuclei. 23 molecules, 23 chromosomes in each two nuclei.
E. 23 molcules (haploid). 46 molecules, 46 chromosomes just prior to DNA synthesis.
| Human cells normally have 46 chromosomes. Let us define the transition from one cell to two cells as meiosis I proceeds. What is the number of nuclear DNA molecules present in a human cell in metaphase I of meiosis? | |
| A. 92 DNA molecules per cell. Found as 92 separate chromosomes. 46 DNA molecules per cell. Found as 46 physically separate chromosomes in each of two nuclei. B. 92 molecules, 46 chromosomes each with two chromatids attached at centromere. 92 molecules, 46 chromosomes each with two chromatids C. 46 molecule, 23 chromosomes each with two chromatids attached at centromere. 46 molecules, 23 chromosomes each with two chromatids. D. 23 molecules, 23 chromosomes in each of two nuclei. 23 molecules, 23 chromosomes in each two nuclei. E. 23 molcules (haploid). 46 molecules, 46 chromosomes just prior to DNA synthesis. |
Solution
B. 92 molecules, 46 chromosomes each with two chromatids attached at centromere. 92 molecules, 46 chromosomes each with two chromatids
During metaphase I, the chromosomes (46 in number) align at the midline or metaphase plate. As the DNA is replicated during the synthesis phase (S phase), total 92 DNA molecules will be there and the chromosomes with the chromatids are attached at the centromere. Each chromosome contains two chromatids, means total 92 chromosomes.
