Mendelian inheritance
- Genes R and Y follow independent assortment. If RRYY produce round yellow seeds and rryy produce wrinkled green seeds, what will be the phenotypic ratio of the F2 generation? Answer: 3. Phenotypic ratio - 9 : 3 : 3 : 1 Key idea: This is a standard dihybrid cross. RRYY x rryy gives F1 RrYy (all round yellow). Selfi... 1
- Which one of the following can be explained on the basis of Mendel's Law of Dominance?A. Out of one pair of factors one is dominant and the other is recessive.B. Alleles do not show any expression and both the characters appear as such in F_2 generat… Answer: 3. A, C, D and E only Key idea: the Law of Dominance covers factors in pairs, dominant and recessive factors, and expression of only... 1
- Match List I with List IIList I: A. Two or more alternative forms of a gene; B. Cross of F_1 progeny with homozygous recessive parent; C. Cross of F_1 progeny with any of the parents; D. Number of chromosome sets in plantList II: I. Back cross; II. P… Answer: 4. A-III, B-IV, C-I, D-II Key idea: match the genetic term with its definition. Alternative forms of a gene: allele (III). Cross of... 1
- In a plant, black seed color (BB/Bb) is dominant over white seed color (bb). In order to find out the genotype of the black seed plant, with which of the following genotype will you cross it? Answer: 3. bb Key idea: an unknown dominant phenotype is tested by a test cross with the homozygous recessive parent. Cross the black plant... 1
- Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) :Mendel's law of Independent assortment does not hold good for the genes that are located closely on the same chromosome.Reason (R… Answer: 4. (A) is correct but (R) is not correct Assertion: genes close together on the same chromosome are linked and tend to be inherited... 1
- Given below are two statements :Statement I :Mendel studied seven pairs of contrasting traits in pea plants and proposed the Laws of InheritanceStatement II :Seven characters examined by Mendel in his experiment on pea plants were seed shape and colo… Answer: 2. Both Statement I and Statement II are correct Mendel studied seven pairs of contrasting traits in pea and proposed the laws of in... 1
- The production of gametes by the parents, formation of zygotes, the F1 and F2 plants, can be understood from a diagram called : Answer: 3. Punnett square The diagram used to show gametes of the parents, the zygotes, and the F1 and F2 genotypes is the Punnett square, d... 1
- How many true breeding pea plant varieties did Mendel select as pairs, which were similar except in one character with contrasting traits ? Answer: 3. 14 Mendel selected 14 true-breeding pea varieties, which formed seven pairs. Each pair differed in only one character with contra... 1
- Select the *correct* match : Answer: 1. Ribozyme – Nucleic acid A ribozyme is an RNA molecule with catalytic activity, so it is a nucleic acid. Morgan is linked to linka... 1
- Which one from those given below is the period for Mendel's hybridization experiments ? Answer: 4. 1856 - 1863 Mendel carried out his hybridization experiments on garden pea from 1856 to 1863. He published the results in 1866. 1
- Among the following characters, which one was not considered by Mendel in his experiments on pea ? Answer: 1. Trichomes - Glandular or non-glandular Key idea: Mendel studied 7 contrasting pairs in pea. Seed colour (green/yellow), pod shape... 1
- A true breeding plant is Answer: 2. near homozygous and produces offspring of its own kind A true-breeding line, after repeated self-pollination, is nearly homozygou... 1
- A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F_1 plants were selfed the resulting genotypes were in the ratio of : Answer: 1. 1 : 2 : 1 :: Tall homozygous : Tall heterozygous : Dwarf Key idea: A TT × tt cross gives all Tt in F₁. Selfing F₁ (Tt × Tt) gives... 1
- Match the terms in Column I with their description in Column II and choose the correct option :Column I: (a) Dominance; (b) Codominance; (c) Pleiotropy; (d) Polygenic inheritanceColumn II: (i) Many genes govern a single character; (ii) In a heterozyg… Answer: 2. (ii) (iii) (iv) (i) Key idea: Match each term with its meaning. Dominance: in a heterozygote only one allele expresses: (ii) Codo... 1