Principles of Inheritance and Variation

If a colour-blind man marries a woman who is homozygous for normal colour vision, the probability of their son being colour-blind is

1. 0.75
2. 0.5
3. 0
4. 1

A true breeding plant is -

1. produced due to cross-pollination among unrelated plants
2. one that is able to breed on its own
3. near homozygous and produces offspring of its own kind
4. always homozygous recessive in its genetic constitution

The movement of a gene from one linkage group to another is called

1. inversion
2. translocation
3. duplication
4. crossing over

Alleles are

1. true breeding homozygotes
2. different phenotype
3. heterozygotes
4. different molecular forms of a gene

Multiple alleles are present

1. on different chromosomes
2. at the same locus of the chromosome
3. at different loci on the same chromosome.
4. on non-sister chromatids

A man with blood group ‘A’ marries a woman with blood group ‘B’. What are all the possible blood groups of their offsprings?

1. A and B only
2. A, B, AB and O
3. A, B and AB only
4. O only

How many pairs of contrasting characters in pea plants were studied by Mendel in his experiments?

1. Eight
2. Five
3. Seven
4. Six

An abnormal human baby with ‘XXX’ sex chromosomes was born due to

1. formation of abnormal sperms in the father
2. fusion of two ova and one sperm
3. formation of abnormal ova in the mother
4. fusion of two sperms and one ovum

Select the incorrect statement with regard to Haemophilia :

1. It is a dominant disease
2. A single protein involved in the clotting of blood is affected
3. It is a recessive disease
4. It is a sex-linked disease

If both parents are carriers for thalassemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child ?

1. 100%
2. 25%
3. no chance
4. 50%