Chapter 20, Problem 1aCP

Define the terms diploid and haploid, and explain how the chromosomal sex of an individual is determined.

Summary Introduction

To review:

The terms diploid and haploid along with the process of determining the chromosomal sex of an individual.

Introduction:

Most of the cells in the human body have 23 pair of chromosomes, that is, 46 chromosomes. Chromosomes are the compact structures formed by the double helix DNA (deoxyribonucleic acid) molecules wrapped around the histone proteins. DNA contains the genetic information inherited by the parents.

Explanation of Solution

Diploid is a condition of a cell where the cell has two sets of chromosomes obtained from parents. The total number of chromosomes in a cell is 46 out of which 23 are obtained from the mother and the remaining 23 are obtained from the father.

Haploid is the condition when the cells have half the number of chromosomes (that is 23). The gametes are the only cells that are present in a haploid state that in turn become diploid after the fertilization of both male and female gametes and result in a diploid zygote.

The female sex chromosome is represented as XX and the male sex is represented as XY. The diagram below depicts the combination of these chromosomes during fertilization and resulting in the formation of the male and female zygote:

The XX combination results in a female child whereas the combination of female X with the male Y chromosome results in a combination of XY, which leads to a male child.