When two genes in a dihybrid cross are situated on the same chromosome close to each other, the proportion of parental gene combinations is:
1.
much higher than the non-parental type
2.
much lower than the non-parental type
3.
equal to the non-parental type
4.
not seen at all
| 1. | It is inherited as an autosomal recessive condition. |
| 2. | The affected individual lacks the enzyme phenylalanine hydroxylase. |
| 3. | The affected individuals lack the capability of converting tyrosine to phenylalanine. |
| 4. | Clinical features include mental retardation and a reduction in hair and skin pigmentation. |
| 1. | Pleiotropy | Sickle cells anaemia |
| 2. | Polygenic inheritance | Human skin colour |
| 3. | Multiple allelism | ABO blood group |
| 4. | Gene/point mutation | Down’s syndrome |
1. Monkeys
2. Drosophila
3. Birds
4. Grasshoppers
Given below are two statements:
| Statement I: | Mendel studied seven pairs of contrasting traits in pea plants and proposed the Laws of Inheritance |
| Statement II: | Seven characters examined by Mendel in his experiment on pea plants were seed shape and colour, flower colour, pod shape and colour, flower position and stem height |
In the light of the above statements, choose the correct answer from the options given below:
1. Statement I is incorrect but Statement II is correct.
2. Both Statement I and Statement II are correct.
3. Both Statement I and Statement II are incorrect.
4. Statement I is correct but Statement II is incorrect.
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): | Closely located genes assort independently. |
In the light of the above statements, choose the correct answer from the options given below:
| 1. | (A) is False, (R) is True. |
| 2. | Both (A) and (R) are True and (R) correctly explains (A). |
| 3. | Both (A) and (R) are True and (R) does not correctly explain (A). |
| 4. | (A) is True, (R) is False. |
The recombination frequency between the genes a & c is 5%, b & c is 15%, b & d is 9%, a & b is 20%, c & d is 24% and a & d is 29%. What will be the sequence of these genes on a linear chromosome?
1. a, c, b, d
2. a, d, b, c
3. d, b, a, c
4. a, b, c, d
1. 100%
2. 25%
3. 50%
4. 75%
Select the correct statements with respect to pleiotropism:
| (a) | A gene is said to be pleiotropic if it affects more than one trait |
| (b) | Phenylketonuria is an example of pleiotropy |
| (c) | A condition where one gene has several alleles is referred to as pleiotropism |
| (d) | A trait is said to be pleiotropic if several genes control it |
Choose the correct answer from the options given below:
1. (a) and (b) only
2. (a) and (d) only
3. (a), (b) and (c) only
4. (b), (c) and (d) only
Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R)
| Assertion (A): | A father will never pass the gene for haemophilia to his sons |
| Reason (R): | Haemophilia is sex-linked (X-linked recessive trait). |
In the light of the above statements, choose the correct answer from the options given below :
| 1. | (A) is True but (R) is False. |
| 2. | (A) is False but (R) is True. |
| 3. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 4. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
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