bchem EOY 2015 (2) — Past Paper Questions & Answers

28 clinical MCQs in Clinical Biochemistry. Barfoed’s test distinguishes;. Kenya, Africa and global revision.

Questions, Answers & Explanations

1. Q1. Barfoed’s test distinguishes;

   • Aldo and keto sugars
   • Pentoses and hexoses
   • Monosaccharides and disaccharides
   • Reducing monosaccharides and disaccharides by controlling heating time.

   Answer: Aldo and keto sugars

2. Q2. Bial’s test is specific for;

   • Pentoses
   • Hexoses
   • Trioses
   • Aldo sugars
   • Keto sugars ~

   Answer: Pentoses

3. Q3. You can distinguish between amylose, amylopectin and glycogen by the color of the test. -

   • Iodine * , ~
   • Molisch’s
   • Seliwanoff s
   • Bial’s
   • Tollen’s

   Answer: Iodine * , ~

4. Q4. Which complex in the electron transport chain does not eee ea SES See (Fe-S)?

   • 1004
   • v awd rticipates in;

   Answer: 1004

5. Q5. The active form of Vitamin Be particrp $

   • Epinephrine
   • Cortisol C, Thyroxine Dz Glucagon
   • Glycogenesis
   • Glycolysis__
   • Insulin

   Answer: Epinephrine

6. Q6. Glucose may be converted to glycerol 3 — phosphate through;

   • Glycerol woe B Acetyl CoA
   • Pyruvate
   • Dihyroxyacetone phosphate (DHAP)
   • glyceraldehydes 3 — phosphate

   Answer: Glycerol woe B Acetyl CoA

7. Q7. To form a triacylglycerol, which of the following is added to diacylglycerol?

   • Glycerol 3-phosphate
   • Acetyl CoA Cc. Fatty acid
   • Fattyacyl CoA
   • DHAP

   Answer: Glycerol 3-phosphate

8. Q8. Which of the following best describes acetylCoA carboxylase, a regulatory enzyme’

   • It is activated by carboxylation
   • It catalyses a reaction that condenses an acetyl group with a malonyl group. C; It catalyses a reaction that requires biotin and ATP. _
   • It converts malonylCoA to acetylCoA
   • It is activated by malonylCoA

   Answer: It is activated by carboxylation

9. Q9. Glycogen storage disease type III is alsoknownas - -/ disease.

   • Gierkes’s /Pompe’s
   • Pompe’s /Andersens’”
   • Cori’s/Forbe’s
   • Cori’s /Hers’
   • Forbe’s/ Hers’

   Answer: Gierkes’s /Pompe’s

10. Q10. Which of the following is not a gluconeogenic substrate?

    • Alanine
    • Thiokinase Known as 2 -KetoacylCoa wane utilize ketone bodies due to C Thiophorase STaSE. . Thiolase
    • AcetylCoA
    • Thiol ™ E Olyase : Thioph POsphatase 14, ‘ What 1s the correct order of ae er. . B-Hydri ction of the following e: Binion
    • PropionylCoA Page 7 of 12 ## Source page 8 / Keto * Snesis oceyrze ; : Urs Cficiency of m kep atocytes but the liver j : | ———__» also 5…

    Answer: Alanine

11. Q11. ary dehygrogenase noylCoA hydratase

    • 1,2,3,4
    • 3,1,4,2
    • 4,3,1,2
    • 4,2,3,1
    • 1,4,3,2

    Answer: 1,2,3,4

12. Q12. Th . 89 ec and: carbon atoms from an odd-chain fatty acid will enter the TCA cycle as acetylCoA

    • Citrate
    • a-ketoglutarate
    • SuccinylCoA ~
    • Fumarate
    • Oxaloacetate

    Answer: Citrate

13. Q13. The role of hormone sensitive triacylgycerol Lipase is to; ~ ) :

    • hydrolyze lipids stored in the liver
    • hydrolyze lipids stored in the adipose tissue CG; hydrolyze lipoproteins entering the liver
    • hydrolyze lipids entering the muscle
    • None of the above.

    Answer: hydrolyze lipids stored in the liver

14. Q14. Mitochondrial HMGCoA synthase participates in ketogenesis. Its cytosolic isoform participates in;

    • Cholesterol synthesis
    • Palmitate synthesis Cc. Triacylglycerol synthesis
    • Phosphoglyceride synthesis
    • MalonylCoA synthesis Page 8 of 12 ## Source page 9 Bors

    Answer: Cholesterol synthesis

15. Q15. one of ie oe carbohydrates will test positive with Fehling solution: : e

    • Starch 7 C
    • Lactose
    • Sucrose
    • Raffinose ;

    Answer: Starch 7 C

16. Q16. The pH of a sample of blood is 7.4, while that of gastric juice is 1.4. Based on this information, the blood sample has

    • 6000 times lower [H’] than the gastric juice
    • A million times lower [H"] than the gastric juice G 0.189 times the [H’] as the gastric juice
    • 5.29 times lower [H’] than the gastric juice
    • 6 times lower [H’] than the gastric juice

    Answer: 6000 times lower [H’] than the gastric juice

17. Q17. The isoelectric point (PJ) for an amino acid is the

    • pKa value of the functional groups attached to the a-carbon atom.
    • Net pKa value for the ionizable side chains Cc. pH at which an amino acid is electrically neutral
    • The same vaiue for aii bui one of the twenty amino acids
    • Is proportional to the number of oxygen atoms of the amino acids, aspartate and glutamate. Page 9 of 12 ## Source page 10

    Answer: pKa value of the functional groups attached to the a-carbon atom.

18. Q18. One of — ri - following is a non-saponifiable lipid : pPhingomyelins a ty

    • Cholesterol]
    • Triacylglycero]
    • Waxes
    • Phosphatidylcholine

    Answer: Cholesterol]

19. Q19. The following statements are true regarding triacylglycrols except.

    • Disulfide bonds
    • Hydrogen bonds .
    • Vander waals :
    • Peptide bonds
    • Hydrophobic interactions

    Answer: Disulfide bonds

20. Q20. Ester-based compounds would be best described by the foltowing general formula.

    • RCOOR
    • RCHO. C
    • RCOOH Dz. RCONH)2
    • ROH.

    Answer: RCOOR

21. Q21. The following statements are true regarding a hydronium ion, except.

    • It is a hydrated proton ; .
    • Its presence in solution makes it basic Cc. Has the structure H30+ oo, ; :
    • Is the usual form of one of the dissociation products of water in solution.
    • Is a hydrated hydrogen ion. Page 10 of 12 ## Source page 11

    Answer: It is a hydrated proton ; .

22. Q22. Denaturation of proteins results in

    • Breakdown of peptide bonds a B. Destruction of hydrogen bonds
    • Disruption of the primary structure.
    • Irreversible change in the molecule
    • Folding of the protein native structure

    Answer: Breakdown of peptide bonds a B. Destruction of hydrogen bonds

23. Q23. Regarding buffer solutions

    • Substrate .
    • Food particle . C3 Substance
    • The strongest buffers are those composed of strong acids and strong bases
    • Coenzyme
    • Reactant particle. Fae

    Answer: Substrate .

24. Q24. Like enzymes, coenzymes can be used:

    • B D OK
    • Rigid structure BE. Globular structure Pave Lf of 12 ## Source page 12 © 36. A steroid vitamin is
    • D 3

    Answer: B D OK

25. Q25. Scurvy is due to the deficiency of

    • Vitamin K :, 8
    • Vitamin B6 ,
    • Vitamin C
    • Vitamin B12
    • Vitamin E

    Answer: Vitamin K :, 8

26. Q26. Folic acid and panthothenic acid are vitamins belonging to a group

    • B-Complex
    • . E G
    • A E, K

    Answer: B-Complex

27. Q27. Megaloblastic anaemia is caused due to the deficiency of

    • Folic acid
    • Vitamin C CG. Vitamin B12 :
    • Folic acid
    • Vitamin B6

    Answer: Folic acid

28. Q28. The metabolism of calcium is normally regulated by: ae

    • Thyroid hormone :
    • Vitamin D Cc. Calmodulin
    • Vitamin C
    • Vitamin E Page 12 of 12

    Answer: Thyroid hormone :