A cross in which an organism showing a dominant phenotype in crossed with the recessive parent in order to know its genotype is called:
1. Back cross
2. Test cross
3. Dihybrid cross
4. Monohybrid cross
ABO blood grouping is controlled by gene I which has three alleles and shows co-dominance. There are six genotypes. How many phenotypes in all are possible?
1. | three | 2. | four |
3. | five | 4. | six |
The fruit fly Drosophila melanogaster was found to be very suitable for experimental verification of the chromosomal theory of inheritance by Morgan and his colleagues because:
1. | a single mating produces two young flies |
2. | smaller female is easily recognisable from a large male |
3. | it completes its life cycle in about two weeks |
4. | it reproduces parthenogenetically |
Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?
1. one X and one Y chromosome
2. two X chromosomes
3. only one Y chromosome
4. only one X chromosome
Test cross in plants or in Drosophila involves crossing:
1. between two genotypes with dominant trait
2. between two genotypes with recessive trait
3. between two F1 hybrids
4. the F1 hybrid with a double recessive genotype
In antirrhinum, two plants with pink flowers were hybridized. The F1 plants produced red, pink, and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridization? Red flower colour is determined by RR, and White by rr genes.
1. | RR | 2. | Rr |
3. | rr | 4. | rrrr |
A test cross is carried out to:
1. | Predict whether two traits are linked |
2. | Assess the number of alleles of a gene |
3. | Determine whether two species or varieties will breed successfully |
4. | Determine the genotype of a plant at F2 |
In order to find out the different types of gametes produced by a pea plant having the genotype AaBb, it should be crossed to a plant with the genotype:
1. AaBb
2. aabb
3. AABB
4. aaBB
Which of the following is not a hereditary disease:
1. Haemophilia
2. Cretinism
3. Cystic fibrosis
4. Thalasasemia
Haemophilia is more commonly seen in human males than in human females because:
1. | This disease is due to a Y-linked recessive mutation |
2. | This disease is due to an X-linked recessive mutation |
3. | This disease is due to an X-linked dominant mutation |
4. | A greater proportion of girls die in infancy |