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10.1 Sickle Cell, Metabolic & Enzyme-Deficiency Disorders β Test 1
Q1. Sickle-cell anaemia is caused by:β A gene (point) mutation
Q2. The sickle-cell substitution at position 6 of the Ξ²-chain changes:β Polar (acidic) glutamate to non-polar valine
Q3. The amino acid substituted and the haemoglobin chain affected in sickle-cell anaemia are:β Valine; Ξ²-globin
Q4. The GluβVal substitution in sickle haemoglobin leads to:β Increased polymerisation of deoxyhaemoglobin
Q5. With respect to its inheritance, sickle-cell disease is:β Recessive (autosomal)
Q6. Sickle-cell anaemia follows which pattern of inheritance?β Autosomal recessive
Q7. Albinism is due to the absence of:β Melanin
Q8. The enzyme deficiency that causes (oculocutaneous type 1) albinism is:β Tyrosinase
Q9. Phenylketonuria (PKU) is caused by the absence/deficiency of:β Phenylalanine hydroxylase
Q10. Patients with phenylketonuria often have lighter hair and skin than their siblings because:β Excess phenylalanine inhibits melanin synthesis (less tyrosine/melanin)
Q11. If a normal adult is placed on a diet completely lacking phenylalanine, which statement is correct?β Tyrosine becomes an essential amino acid
Q12. Alkaptonuria is characterised by the accumulation of:β Homogentisic acid
Q13. Lesch-Nyhan syndrome is caused by a deficiency of:β Hypoxanthine-guanine phosphoribosyltransferase (HGPRT)
Q14. Gaucher's disease is a disorder of abnormal ___ metabolism:β Lipid (sphingolipid)
Q15. Tay-Sachs disease involves abnormal metabolism of:β Lipid (ganglioside)
Q16. Tay-Sachs disease results from a defect localised to which organelle?β Lysosome
Q17. The clinical impact of Tay-Sachs disease falls mainly on the:β Brain (central nervous system)
Q18. Cystic fibrosis is caused by a defect in which type of membrane channel?β Chloride channel (CFTR)
Q19. The most common cystic-fibrosis mutation (ΞF508) is a:β Deletion (of three nucleotides removing one amino acid)
Q20. Match each disorder with its deficient enzyme/protein and select the correct option.β A-iii, B-i, C-iv, D-ii