1. Which sex-linked disorder is characterised by abnormal bleeding and failure of the blood to clot? spina bifida haemophilia cystic fibrosis haemorrhoids

2. Which sex-linked disorder is also known as daltonism? muscular dystrophy epilepsy red-green colour-blindness haemophilia

3. Which of the following diseases is a sex-linked disease characterised by marked weakness and wasting of the muscles? carpal tunnel syndrome myasthenia gravis rheumatoid arthritis muscular dystrophy

4. After Down's syndrome, which sex-linked disorder is the most common genetic cause of mental retardation? fragile X syndrome hypothyroidism thalassaemia Tay-Sachs disease

5. Colour-blindness is a sex-linked disorder. Patients are tested for colour-blindness with the use of a series of pictures made up of coloured dots. What is the name of this test? Hashimoto colour test Snellen colour test Ishihara colour test Kawasaki colour test

6. Almost all sex-linked disorders are carried on the X-chromosome. Why are Y-linked disorders so rare? because you have to inherit two Y-chromosomes for a disease to show up because the genes on the Y-chromosome are always masked by other genes because only the X-chromosome is genetically active because the Y-chromosome carries very few genes

7. Other than determining the male gender, which human condition is known to be determined by genes carried on the Y-chromosome? ear-wiggling snoring hairy ears tongue-rollling

8. Turner's syndrome is caused by the absence of one of the sex chromosomes. Which of the following statements is NOT true about patients with Turner's syndrome? they are usually very short in stature they are always female they are hermaphrodites (have both male and female reproductive organs) they are infertile

9. Klinefelter's syndrome is a genetic defect in which the patient has three sex chromosomes. Which of the following patterns best describes the typical patient with this disorder? XXY (patient appears to be male) XXY (patient is a hermaphrodite - has both male and female sex organs) XYY (patient is male) XXX (patient is female)

10. Which sex-linked disease has affected most of the royal families in Europe? phenylketonuria muscular dystrophy colour-blindness haemophilia