Question

A cell in the testes of a male bald eagle is getting ready to begin meiosis. The diploid number for this bird species is 66. How many replicated chromosomes are there in this testicular cell at metaphase I? How many sister chromatids are there in metaphase I? In each daughter cell, how many sister chromatids are there in prophase II? How many chromosomes are there in each sperm cell?

Answer 1

At metaphase I in eagle testicular cell, there are 66 replicated chromosomes and 132 sister chromatids. During prophase II, each daughter cell will have 33 sister chromatids. Upon completion of meiosis II, each sperm cell will have 33 chromosomes.

Step-by-step explanation:

When a cell in the testes of a male bald eagle, which has a diploid number of 66, is preparing to undergo meiosis, it will first replicate its DNA during interphase. At metaphase I, there would be 66 replicated chromosomes, because the chromosomes have paired up but not yet separated into daughter cells. Since each replicated chromosome consists of two sister chromatids joined at the centromere, there would be a total of 132 sister chromatids at metaphase I.

In meiosis II, specifically prophase II, each daughter cell from meiosis I will have 33 sister chromatids, since the cells are now haploid. Finally, when meiosis II is completed, each sperm cell, which is a gamete, will have 33 chromosomes (haploid).

Answer 2

Replicated chromosomes at metaphase I = 66

Sister chromatids at metaphase I = 66 x 2 = 132

Sister chromatids at prophase II = 66

Chromosomes in each sperm cells = 33

Step-by-step explanation:

Metaphase I of meiosis I would have 66 replicated chromosomes in the testicular cells of the bird. Each of the replicated chromosomes would have two sister chromatids. So, a total of 66 replicated chromosomes would have 66 x 2 = 132 sister chromatids.

Due to segregation of homologous chromosomes towards opposite poles in anaphase I, each daughter cell formed by the end of meiosis I would have 33 replicated chromosomes. So, each of the daughter cells would have a total 33 x 2 = 66 sister chromatids at prophase II.

Since meiosis II maintains the chromosome number, each sperm cell formed by the end of meiosis II would have 33 chromosomes.