Question

The nucdlear DNA content of a single sperm cell varies depending on the species of the organism. If the amount of DNA in a single sperm cell is 2.5 picogram(s), calculate the amount of DNA at different stages of meiosis. Part A What would be the expected nuclear DNA content (in picograms) of the cell before DNA replication has occurred in Interphase I (before S phase) ?Part B What would be the expected nuclear DNA content of a cell at metaphase 1?

Answer 1

Answer:

1. 5 pg of DNA.

2. 10 pg of DNA.

Explanation:

The process of meiosis results in the production of the four haploid daughter cells and is involved in the formation of sexual gametes. The sperm cells produced as a result of the meiosis are haploid in their ploidy and therefore contains only "C" amount of DNA.

1. During interphase

The sperms are formed from the diploid spermatocytes which contain 2C amount of DNA. During the cell cycle before the M phase, cell replication takes place in the S phase. The synthesis phase doubles the amount of DNA  and forms 2C to 4C.

Therefore before the S phase or in G1 phase, the DNA amount will be 2C or 2 x 2.5= 5 pg of DNA.

2. At metaphase

After S phase, the amount of DNA increases to 4C which gets distributed during the anaphase that is after the metaphase. Therefore, the amount of DNA during metaphase will be 4C or 4 x 2.5 = 10 pg.