Chapter 19, Problem 1RQ

Define the difference between (a) gene and allele, (b) dominant allele and recessive allele, (c) homozygote and heterozygote, and (d) genotype and phenotype.

Summary Introduction

To differentiate: Gene and allele

Introduction: Genetics is the study of genes and their inheritance patterns. Allele and gene are two common terms used in genetics.

Explanation of Solution

A gene includes a set of nucleotides that code for a particular trait.

An allele is a variant of a gene for the same trait coded by the gene.

Summary Introduction

To differentiate: Dominant and recessive allele.

Introduction: Genetics is the study of genes and their inheritance patterns. An allele is a variant of a gene for the same trait coded by the gene. Dominant and recessive alleles are two common terms used in genetics.

Explanation of Solution

The allele that is expressed in the heterozygous condition of two alleles is called as a dominant allele.

The recessive allele can be expressed only in homozygous condition. In heterozygous condition, the dominant allele masks its effects.

Summary Introduction

To differentiate: Homozygote and heterozygote.

Introduction: Genetics is the study of genes and their inheritance patterns. Homozygote and heterozygote are two common terms used in genetics. An allele is a variant of a gene for the same trait coded by the gene. Homologous chromosomes are a pair of chromosomes where one chromosome was obtained from the male gamete and the other from the female gamete at the time of the union of the nucleus during formation of zygote.

Explanation of Solution

The homozygote or homozygous condition is where the same allele is present on both the homologous chromosomes. Both the alleles are either dominant or recessive.

The heterozygote or heterozygous condition is where different alleles are present on both the homologous chromosomes. One allele is dominant and the other is recessive.

Summary Introduction

To differentiate: Genotype and phenotype

Introduction: Genetics is the study of genes and their inheritance patterns. Genotype and phenotype are two common terms used in genetics.

Explanation of Solution

The genetic makeup of an organism having genes that code for a particular trait of an individual trait is called as genotype.

The morphological or biochemical or physiological expression of the trait of the gene that encodes the trait is called the phenotype.