Quelpr
3 marksGenetic Concepts

CSEC Biology · January 2017 · Paper 2 · Question 3(c)(iii)

Some people inherit haemophilia, a condition where blood doesn't clot normally. The allele for blood clotting is on the X chromosome. A female with normal blood clotting ability mates with a male with normal blood clotting ability to produce offspring.

What is the likely sex of the haemophiliac child? Give ONE reason to support your answer.

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 3(a)(i)Identify the components of blood that are labelled A, B and C in Figure 1. A B C[3 marks]
  2. 3(a)(ii)Name the component of the blood that is responsible for clotting.[1 mark]
  3. 3(b)Complete the flow diagram shown in Figure 2 by filling in the missing words at positions D, E and F.[3 marks]
  4. 3(c)(i)Complete the following genetics diagram to illustrate this information. Parents' phenotypes: Male x Female Parents' genotypes: x XHXh Gametes: x (XH)(Xh)…[3 marks]
  5. 3(c)(ii)State the probability of the couple having a haemophiliac child.[1 mark]
  6. 3(d)Suggest ONE reason why haemophiliacs may be more susceptible to infectious disease.[1 mark]

More practice: the rest of this paper · more Genetic Concepts questions · all CSEC Biology past papers