Heredity And Variations - Biology Jamb Past Questions and Answers

Question 41 :

• JAMB 1994

In the gene locus for eye colour in humans, the allele for brown eye is dominant over the allele for blue eyes. If a homozygous brown-eyed girl has a brother with blue eyes, what are the likely phenotypes of there parents'eye colour (Eye colour is not a sex linked trait)

A. Both parents have blue eyes
B. Their father has blue eyes and their mother has brown eyes
C. Both parents have brown eyes
D. Their mother has the blue eyes and their father has the brown eyes

Question 42 :

• JAMB 1994

If a woman's genotype is Tt Qq Rr, what would be the gene content of her eggs?

A. TQr, tqr
B. TQR, tqr
C. TqR, tQr
D. TQr, TQR

Question 43 :

• JAMB 1994

The sex-linked defect in which very slight cut produces severe bleeding is known as

A. Anaesmia
B. Anorexia
C. Haemophilia
D. Haemolysis

Question 44 :

• JAMB 1994

A man who has the trait for colour blindness marries a normal woman. What percentage of their children would be sufferers, carriers and normal respectively

A. 25%, 25% and 50%
B. 25%, 50% and 25%
C. 50%, 25% and 25%
D. 25%, 37.5% and 37%

Question 45 :

• JAMB 1995

A man with blood group a is married to a woman with blood group A. Which of the following group combinations is possible if the family has three children?

A. B, A, AB
B. O, A, B
C. B, AB, AB
D. A, O, A