Chapter 10, Problem 7A

Summary Introduction

Introduction:

In animals the sexual life cycle involves meiosis. Meiosis involves two consecutive cell divisions called meiosis I and meiosis II. The two divisions produce a set of four haploid daughter cells that are not identical. Meiosis is important because it results in genetic variation.

Answer to Problem 7A

Correct answer :

The correct answer is option C. Homologous chromosomes have the exact same type of allele at the same location

Explanation of Solution

Explanation/justification for the correct answer:

OptionC. Homologous chromosomes have the exact same type of allele at the same location

−Homologous chromosomes are pairs of chromosomes that have the same length, centromere position, pairs together during meiosis and have the same gene sequence. They are similar but not exactly identical. They carry the same genes in the same order but the alleles for each trait may be different on each chromosome. This ensures that the phenotypes are different for the same genes. So this statement is not true for homologous chromosomes. Hence, this is the correct option.

Explanation for incorrect answer:

Option A. Homologous chromosomes have the same length- Homologous chromosomes have the same length. They are held tightly together along their lengths during prophase I. Hence, this is not the correct option.

Option B. Homologous chromosomes have the same centromere position- In the homologous chromosomes the location of the centromere is same. Hence, this is not the correct option.

Option D. Homologous chromosomes pair up during meiosis I- The pairs of homologous chromosomes come together during prophase of meiosis I in a process called synapsis. Hence, this is a feature of homologous chromosomes and so this is not the correct option.