Somatic cells of lions contain 36 chromosomes How many chro

. Somatic cells of lions contain 36 chromosomes. How many chromosomes and how many molecules of DNA are present in each of the following stages of cell division? Chromosomes DNA

G1 of the cell cycle _____________ _____________

G2 of the cell cycle _____________ _____________

Anaphase of mitosis _____________ _____________

Anaphase I of meiosis _____________ _____________

Anaphase II of meiosis _____________ _____________

Explain your rationale for G2 phase:

Solution

G1 phase- 36 chromosomes

G2 phase- 72

Anaphase of mitosis - 36 in each of the two dividing daughter cells.

Anaphase I of meiosis- 36 in each of the two dividing daughter cells.

Anaphase II of meiosis - 18 in each of the four dividing daughter cells.

G1 contains the normal 36 chromosomes. After G1, synthesis or DNA replication takes place. Each chromosome gets replicated doubling the number of chromosomes. Therefore G2 would contain double the number of chromosomes in G1. It proceeds through prohase and metaphase. The chromosomes would be distributed equally among two daughter cells in anaphase. Therefore, anaphase would contain half the number of chromosomes in G2 phase I.e, normal chromosome number (36) is restored.

In meiosis, replication takes place only once but divides twice. Therefore anaphase II of meiosis would contain 18 singlet chromosomes.