Question

Define the following terms:
(a) Homozygous, (b) heterozygous, (c) Genotype, (d) Phenotype, (e) Dominant, (f) Recessive, (g) Allele, (h) Back cross, (i) Multiple alleles

Answer 1

Hint: The biological process in which the genes of parents are transferred to their progeny or offspring is called heredity, and the study of heredity is referred to as genetics. The genes in the offspring are inherited from both the parents.

Complete answer:
(a) Homozygous is the term used for a specific gene which has similar alleles over both the homologous chromosomes.
(b) Heterozygous is the term used for a specific gene of an organism which has two diverse types of alleles. An organism is said to be heterozygous if it has inherited a different type, a distinct gene from individual parents. Moreover, a heterozygous genotype signifies to have opposite features as compared to a homozygous genotype. When an organism carries two copies of identical dominant alleles, then it is said to be homozygous dominant, whereas if it carries two copies of similar recessive allele, then it is recognized as homozygous recessive.
(c) The term genotype of an organism signifies its genetic constituents. The genotypic properties of an organism cannot be identified or recognized just by seeing from outside, so the genotypic studies are crucial. A genotypic feature of an organism is found within their chromosomes and therefore it cannot be identified and noticed.
(d) The term phenotype can be defined as the properties or traits of an organism which could be possibly observed as outward appearances. The genotypic studies assist for initial classification amongst the species belonging to the same groups.
(e) A gene is said to be dominant if it suppresses the activities of the other gene.
(f) A gene is said to be recessive when its effect is suppressed by the dominant gene.
(g)An allele, also known as allelomorph, is defined as an alternate form of a specified gene. They can occur in pairs or as multiple types.
(h) Back cross is the process of crossing of a hybrid variety with one of its parent types so as to attain the offspring having genetic properties very similar to that parent.
(i) Multiple alleles comprises three or more alternate types of a specific gene which could potentially occupy the similar locus.

Note: Broadly, the genotypes are categorized into three different types, named as homozygous recessive, homozygous dominant, and heterozygous.