51.

A woman with normal vision, but whose father was colourblind, marries a colourblind man. Suppose that the fourth child of this couple was a boy. This boy

• must have normal colour vision

• will be partially colourblind since he is heterozygous for the colourblind mutant allele

• must be colourblind

• may be colourblind or may be of normal vision

Which of the following is not a hereditary disease?

• Cretinism

• Cystic fibrosis

• Thalassaemia

• Haemophilia

de Vries gave his mutation theory on organic evolution while working on

• Althea rosea

• Drosophila melanogaster

• Oenothera lamarckiana

• Pisum sativum

A patient is generally advised to specially, consume more meat, lentils, milk and eggs in diet only when he suffers from

• kwashiorkor

• rickets

• anaemia

• scurvy

Which one of the following makes use of RNA as a template to synthesize DNA?

• Reverse transcriptase

• DNA dependant RNA polymerase

• DNA polymerase

• RNA polymerase

A woman with 47 chromosomes due to three copies of chromosome 21 is characterized by

• Down syndrome

• triploidy

• Turner syndrome

• super femaleness

AIDS is caused by HIV that principally infects

• all lymphocytes

• activator B cells

• T₄ lymphocytes

• cytotoxic T cells

If mammalian ovum fails to get fertilized which one of the following is unlikely?

• Corpus luteum will disintegrate

• Estrogen secretion further decreases

• Primary follicle starts developing

• Progesterone secretion rapidly declines

Which group of three of the following five statements (A- E) contain is all three correct statements regarding beri- beri?

A. A crippling disease prevalent among the native population of sub- Sahara Africa.

B. A deficiency disease caused by lack of thiamine (vitamin- B₁).

C. A nutritional disorder in infants and young children when the diet is persistently deficient in essential protein.

D. Occurs in those countries where the staple diet is polished rice.

E. The symptoms are pain from neuritis, paralysis, muscle wasting, progressive oedema, mental deterioration and finally heart failure.

• A, B and D

• B, C and E

• A, C and E

• B, D and E

At which latitude, heat gain through insolation approximately equals heat loss through terrestrial radiation?

• 66$°$ North and South

• $22\frac{1}{2}°$ North and South

• 40$°$ North and South

• $42\frac{1}{2}°$ North and South