Statement I: | In situation A, the plant with the dominant phenotype [genotype unknown] must be homozygous dominant. |
Statement II: | In situation B, the plant with the dominant phenotype [genotype unknown] must be heterozygous. |
Assertion (A): | Dominance is not an autonomous feature of a gene or the product that it has information for. |
Reason (R): | The frequency of a gene or an allele in a population is ultimately decided by factors such as natural selection. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
Statement I: | X will be parental types (98.7%) and recombinant types (1.3%); Y will be parental types (62.8%) and recombinant types (37.2%) |
Statement II: | The strength of linkage is inversely proportional to the distance between the genes located on the same chromosome. |
1. | 2 genes | 2. | 3 genes |
3. | 4 genes | 4. | 6 genes |
1. | 6/64 | 2. | 15/64 |
3. | 20/64 | 4. | 1/64 |
I: | Polygenic inheritance takes into account the influence of the environment. |
II: | In a polygenic trait, the phenotype reflects the contribution of each allele, i.e., the effect of each allele is additive. |
III: | The normal distribution curve is bell-shaped in polygenic inheritance. |
IV: | It is also known as quantitative inheritance. |
1. | 0 | 2. | 1 |
3. | 3 | 4. | 4 |
I: | Where a single gene can exhibit multiple phenotypic expressions, such a gene is called a pleiotropic gene. |
II: | The underlying mechanism of pleiotropy in most cases is the effect of a gene on metabolic pathways which contribute towards different phenotypes. |
III: | Phenylketonuria is caused by a defect in the gene that codes for the enzyme phenylalanine hydroxylase and manifests itself through phenotypic expression characterised by mental retardation and a reduction in hair and skin pigmentation. |
1. | Statement I is correct, Statement II is correct, Statement III is incorrect. |
2. | Statement I is incorrect, Statement II is correct, Statement III is incorrect. |
3. | Statement I is correct, Statement II is incorrect, Statement III is correct. |
4. | Statement I is correct, Statement II is correct, Statement III is correct. |
A | ||
B | |
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1. | Only A | 2. | Only B |
3. | Both A and B | 4. | Neither A nor B |
I. | The sex determination in honey bee is based on the number of sets of chromosomes an individual receives. |
II. | An offspring formed from the union of a sperm and an egg develops as a female (queen or worker), and an unfertilised egg develops as a male (drone) by means of parthenogenesis. |
III. | The males have double the number of chromosomes than that of a female, therefore, the females are haploid having 16 chromosomes and the males are diploid, i.e., having 32 chromosomes. |
IV. | This is called a haplodiploid sex-determination system. |
V. | The males produce sperms by mitosis, they do not have a father and thus cannot have sons, but have a grandfather and can have grandsons. |
1. | 2 | 2. | 3 |
3. | 4 | 4. | 5 |