What decides the frequency of an allele in a population?
1. | Dominance |
2. | Its location on a particular chromosome |
3. | Its degree of expression |
4. | Natural selection |
It is said that Mendel proposed that the factor controlling any character is discrete and independent. His proposition was based on the:
1. | results of the F3 generation of a cross |
2. | observations that the offspring of a cross made between the plants having two contrasting characters shows only one character without any blending |
3. | self-pollination of F1 offspring |
4. | cross-pollination of F1 generation with recessive parent |
Assertion (A): | When two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters. |
Reason (R): | During gamete formation, the alleles for each gene segregate from each other. |
1. | (A) is True but (R) is False |
2. | Both (A) and (R) are True and (R) is the correct explanation of (A) |
3. | Both (A) and (R) are True but (R) is not the correct explanation of (A) |
4. | (A) is False but (R) is True |
1. | Mendel found the phenotype of the F1 heterozygote Tt to be exactly like the TT parent in appearance. |
2. | He proposed that in a pair of dissimilar factors, one dominates the other. |
3. | It is convenient (and logical) to use the capital and lower case of an alphabetical symbol to remember this concept of dominance and recessiveness. |
4. | It is convenient (and logical) to use the capital and lower case of different alphabets symbol to remember this concept of dominance and recessiveness. |
Statement I: | The dominant phenotype can be produced only by an organism with a homozygous dominant genotype. |
Statement II: | The results of a test cross indicate whether an individual with the dominant phenotype is heterozygous or homozygous dominant. |
1. | Statement I is correct; Statement II is correct |
2. | Statement I is correct; Statement II is incorrect |
3. | Statement I is incorrect; Statement II is incorrect |
4. | Statement I is incorrect; Statement II is correct |
Statement I: | In co-dominance, the F1 progeny resembles neither of the parents. |
Statement II: | In incomplete dominance, the F1 progeny resembles both parents. |
1. | Statement I is correct; Statement II is correct |
2. | Statement I is correct; Statement II is incorrect |
3. | Statement I is incorrect; Statement II is correct |
4. | Statement I is incorrect; Statement II is incorrect |
Consider the given two statements:
Statement I: | In incomplete dominance and co-dominance, the F2 phenotypic ratio and genotypic ratio are identical. |
Statement II: | Incomplete dominance and co-dominance are examples of blending inheritance. |
1. Only Statement I is correct.
2. Only Statement II is correct.
3. Both Statement I and Statement II are correct.
4. Both Statement I and Statement II are incorrect.
I. | The dominant allele masks the expression of the recessive allele. |
II. | Dominance is an all-or-nothing feature. |
III. | Dominance can sometimes be incomplete. |
I: | If both parents are carriers for an autosomal recessive genetic disorder, there is a 25% chance that any child they have will express the disorder. |
II: | In Incomplete dominance, the F2 phenotypic and genotypic ratios are identical. |
III: | Codominance involves the expression of both alleles at a locus in a heterozygote. |
IV: | A testcross involves crossing a homozygous recessive individual with an individual whose genotype is unknown. |
Assertion (A): | Although Mendel published his work on inheritance of characters in 1865 but it remained unrecognised till 1900. |
Reason (R): | In 1900, three Scientists, Avery, Macleod, McCarty, independently rediscovered Mendel’s results on the inheritance of characters. |
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. |