Chapter 11, Problem 3STP

Summary Introduction

Introduction:

Reproductive cells which pass on genetic traits from the parent to child are produced by the process of meiosis. In order to maintain the same number of chromosomes in each generation, an organism produces gametes. Gametes are sex cells and have half the number of chromosomes.

Answer to Problem 3STP

Correct answer :

The correct answer is option C. 3 and 7

Explanation of Solution

Explanation/justification for the correct answer:

Option C. 3 and 7 −During metaphase of meiosis I, pairs of homologous chromosomes line up at the equator of the cell. During anaphase I the homologous chromosomes separate and move to opposite poles of the cell. At the end of meiosis I the daughter nuclei have half the number of chromosomes. One chromosome from each pair of homologous chromosomes enters the daughter cell. In anaphase II the sister chromatids separate and move to opposite poles. At the end of meiosis II, four new cells are formed with nuclei containing only one sister chromatid of the homologous pair. During gamete formation, the sister chromatids separate and they are randomly distributed. So in gametes, the chromosome 3 and 7 are more likely to be found together. Hence, this is the correct option.

Explanation for incorrect answer:

Option A. 1 and 2- Chromosomes 1 and 2 form homologous pair. During gamete formation, they will separate and enter different gametes. Hence, this is not the correct option.

Option B. 3 and 6- Chromosomes 3 and 6 will separately enter different gametes so they will not be found together. Hence, this is not the correct option.

Option D. 5 and 6- Chromosomes 5 and 6 are sister chromatids so they will separate during meiosis II. Hence, this is not the correct option.