The point mutation leading to sickle cell anaemia occurs:

1. at sixth position in the beta chain of haemoglobin
2. at sixth position in the alpha chain of haemoglobin
3. at sixth position in the beta chain of myoglobin
4. at sixth position in the alpha chain of myoglobin

In cases of Phenylketonuria:

1. The affected individual lacks an enzyme that converts the amino acid tyrosine into phenylalanine.

2. The affected individual makes an enzyme that converts the amino acid tyrosine into phenylalanine.

3. The affected individual makes an enzyme that converts the amino acid phenylalanine into tyrosine.

4. The affected individual lacks an enzyme that converts the amino acid phenylalanine into tyrosine.

Monosomy means:
1. Lack of one pair of chromosomes
2. Lack of one of any one pair of chromosome
3. Presence of an extra chromosome
4. Presence of an extra set of chromosomes

Mendelian disorders are mainly determined by:
1. Alteration or mutation in a single gene.
2. Chromosomal gross structural changes.
3. Recombination between linked genes.
4. Jumping genes

During his observation of spermatogenesis in a few insects, Henking found that a nuclear structure was received by 50 % of the sperms. What did he call this structure?

1. X – body

2. Y – body

3. X – chromosome

4. Y – chromosome

‘When two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters’. This is the statement of:

1. Law of Dominance

2. Law of segregation

3. Law of Independent Assortment

4. Law of Linkage

To study whether a gene exhibits multiple allelism or not one must study:
1. An individual
2. A population
3. A species
4. With concentration

What can be the blood groups of progeny whose father and mother are of AB and O blood group respectively?
1. A and B only

2. AB only

3. All except O

4. A, B, AB and O

Blood group antigens are:
1. Carbohydrates present in plasma
2. Carbohydrates present on the surface of RBCs
3. Plasma proteins
4. Proteins present on the surface of RBCs

What is the F₂ phenotypic ratio in cases of incomplete dominance?
1. 1 : 1

2. 3 : 1

3. 1 : 2 : 1

4. 1 : 1