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ANSWER:, , a. Hereditary characters are transferred from, parents to offsprings by.gene, hence they are, said to be structural and functional units of, heredity., , b. Organisms produced by asexual, reproduction show minor variations., , c. The component which is in the nuclei of, cells and carries the hereditary characteristics, is called chromosome., , d. Chromosomes are mainly made up of DNA., , e. Organisms produced through sexual, reproduction show major variations.

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2. Explain the following., , a. Explain Mendel’s monohybrid progeny with, the help of any one cross., , Answer:, , « Mendel brought about a cross between, two pea plants with only pair of, contrasting characters. This type of cross, , is called a monohybrid cross., , Tall pea plants and dwarf pea plants were, used in this cross. Hence this is parent, , generation (P;)., Mendel’s experiment of the Monohybrid Cross, Parental Generation (P,), , Phenotype: Tall Dwarf, Genotype: TT tt, Gametes: T t, , First Filial \f, Generation (F,) t, Phenotype: Tall, Parental Generation (P,) _Selfing in F,, Phenotype: Tall Tall, Genotype: Tt Tt, Gametes: Tandt Tandt, Second Filial, , , , — Male gamete] > t, Generation (F,) ies, , Female gameto~, , T TT (Tall) Tt (Tall), t Tt (Tall) | tt (Dwarf), , , , , , , , , , All the plants produced in F; genration are, tall, having genotype Tt. This indicates, that the gene responsible for tallness in, pea plants is dominant over the gene, , responsible for dwarfness., , When F; plants are self pollinated they, produce second filial generation (Fz)., In Fz generation both tall and dwarf plants, , appeared in the ratio 3:1., , Thus, the genotypic ratio of Fz generation, is 3 (Tall) : 1 (Dwarf) and the genotypic, ratiois 1 TT: 2 Tt: 1 tt.

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c. Distinguish between monohybrid and dihybrid, , cross., , Answer:, , Monohybrid cross, , (i) Cross involving a, single pair of, contrasting characters, is called monohybrid, , cross., , (ii) F, plants of, monohybrid cross, produce two types of, , gametes., , (iii) Monohybrid cross, , has a phenotypic ratio, , of 3: 1 in F generation., , Dihybrid cross, , (i) Cross involving two, pairs of contrasting, characters is called a, , dihybrid cross., , (ii) F, plants of dihybrid, cross produce four, , types of gametes., , (iii) Dihybrid cross has, a phenotypic ratio of 9:, 3:3:1inF,, , generation.

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d. Is it right to avoid living with a person, suffering from a genetic disorder?, , Answer:, , ¢ No, it is not right to avoid living with a, person suffering from a genetic disorder., , ¢ Genetic disorders are transmitted from, parents to offsprings only and they are, non-contagious, i.e., they do not spread, , from one person to another through, , contact.