Heredity - 1 - Free MCQ Practice Test with solutions, UPSC Sci & Tech

Genes carry instructions that tell cells how to make proteins. These proteins perform many functions in the body and are responsible for controlling an organism’s characteristics or traits, such as height, eye color, or blood type.

Genes do not decide the environment, and they do not directly control appearance on their own—traits are expressed through the proteins they help produce.

One parent is homozygous for one allele, and the other parent is homozygous for the other allele. The offspring make up the first filial (F1) generation. Every member of the F1 generation is heterozygous and the phenotype of the F1 generation expresses the dominant trait.

DNA present in the nucleus acts as the primary information source for making proteins. It stores genetic instructions, which are first transcribed into messenger RNA (mRNA). The mRNA then serves as a template during translation to synthesize specific proteins.

Tall with round seeds

Since tallness of plant and round shape of seeds are dominant characters, these will be expressed phenotypically or externally.

Germ cells (sperms and eggs) are formed by the process of meiosis, which reduces the chromosome number to half (haploid). Each germ cell receives one chromosome from each homologous pair. When the male and female gametes fuse during fertilization, the diploid chromosome number is restored, maintaining the stability of the chromosome number in the progeny.

F2 Generation (Second Filial Generation):

The result shows a phenotypic ratio of 3:1:

3 purple-flowered plants (dominant phenotype)

1 white-flowered plant (recessive phenotype)

This 3:1 ratio is the classic Mendelian phenotypic ratio for a monohybrid cross.

Sexual reproduction involves the participation of two parents for the process of reproduction. During fertilization, the fusion of male and female gametes results in the creation of a zygote with a full set of chromosomes. This leads to the sharing of genetic information between the parents.

Humans follow XX- XY mechanism of sex determination.

Proteins function as enzymes, hormones, and structural components that regulate and control the body’s biochemical processes. By controlling the efficiency and rate of activities like hormone production, metabolic reactions, and cell signaling, proteins influence the expression of characteristics or traits in organisms

The genetic material for a child is equally contributed by both parents. An organism develops from zygote which in turn is product of fusion of male and female gamete.