TECHNICAL UNIVERSITY OF MOMBASA Faculty of ENGINEERING & TECHNOLOGY DEPARTMENT OF MEDICAL SCIENCES FACULTY OF APPLIED AND HEALTH SCIENCES BMLS 13M MID ENTRY ABT 4202 : BIOCHEMISTRY II INSTRUCTIONS: END OF SEMESTER EXAMINATIONS SERIES: AUGUST 2013 TIME: 2 HOURS 1. This paper consists of Two sections, Answer all questions in A and B. 2. This paper consists of Seven printed pages SECTION A 1. Which of the following lists the pyrimidine nucleotides A. Adenine and cytosine B. Guanine and thymine C. Cytosine and thymine D. Adenine and guanine E. Proline and alanine 2. The lock and key model of enzyme action illustrates that a particular enzyme molecule. A. Forms a permanet enzyme- substrate complex B. May be destroyed and resythesized several times. C. Interacts with a specific type of substrate molecule D. Reacts at identical rates under all conditions E. Is in activated at low temperature. 2013 Technical University of Mombasa Page 1
3. Which one of the following metabolic path ways is common in aerobic and anaerobic organisms. A. Oxidative phosphorylation B. Glycolysis C. The citric acid cycle D. Gluconeogesis E. Pentose phosphate pathway 4. Which one of the following molecule is produced in the pentose phosphate pathway. A. NADPH B. Glucose C. Pyruvate D. HEXOKINASE E. Glucose 6- phosphate 5. Alycolysis 6. Pyruvate A. Does not occur in bacterial cells B. Takes place in all cells C. Does not occur in yeast cells D. Does not occur in animal cells E. Occurs only in animal cells A. Is the molecule that starts the citric and cycle. B. Is the end product of oxidative phosphorylation C. Is a six carbon molecule D. Forms at the end of glycolysis E. Forms at the end of gluconeogenesis 7. An enzyme that hydrolyses protein will not act on starch. This fact is an indication that enzymes are A. Hydrolytic B. Specific C. Catalylic D. Synthetic E. Organic 8. At high temperature the rate of enzyme action decreases because the increased heat. A. Changes the PH of the system B. Alters the active site of the enzyme C. Neutralize acids and bases in the system. D. Increases the concentration of enzymes E. Reduces the number of amino acids 2013 Technical University of Mombasa Page 2
9. ----------------- occurs when the inhibitory chemical, which does not have to resemble the substrate, binds to the enzymes at a site other that the active site. A. Non-competitive inhibition B. Competitive inhibition C. Uncatalyzed reaction D. Stimulated reaction E. Non reactive inhibition 10. If an enzyme solution is saturated with substrate, the most effective way to obtain an even faster yield of products would be A. Add more of the enzymes B. Add more substrate C. Add an allosteric inhibitor D. Add as non competitive inhibitor E. Add a co enzyme 11. Which of the following are pyrimidines in RNA? A. Adenine B. Guanine C. Thymine D. Uracil E. Alanine 12. Which of the following is an example of denaturation? A. Evaporation of sweat on skin surface B. Formulation of Micelles C. Enzymes losing function when heated D. Hydrogenation of oils E. Melting of fats 13. The bonding of unit molecules to produce a polysaccharide is called. A. Hydrolysis B. Translation C. Cellular respiration D. Dehydration. E. Transamination 14. Which one is not an attribute of enzymes. A. Specific in nature B. Protein in chemistry C. Consumed in reaction D. Increases rate of reaction E. Activity is affected by temperature change 2013 Technical University of Mombasa Page 3
15. Which of the following is made up of amino acid molecules? A. Adipose tissue B. Lipases C. Glycogen D. RNA E. DNA 16. An unsaturated fat could be changed into a saturated fat if A. Peptide bounds were broken B. Hydrogen atoms were added C. Glycerol molecules were added D. Fatty acid chains were shortened E. Fatty acid chains were made longer. 17. The following bonds are found in lipids A. Peptide bonds B. Ester bonds C. Glycosidic bounds D. Nuclear bonds E. Lipobonds 18. Which of the following is the monomer of DNA? A. Triglyceride B. RNA C. Nucleotide D. Steroid E. Nucleoside 19. Which of the following represents the structure of a nucleotide A. Salt lipid base B. Glucose-glucose glucose C. Phosphate-sugar nitrogenous base D. Amino acid-amino acid-amino acid E. Sugar- nitrogenous base 20. The bonding of three amino acids would result into. A. Triglyceride B. Polypeptide C. Phospholipid D. Polysaccharide\ E. Nucleic acid 2013 Technical University of Mombasa Page 4
21. A characteristic of saturated fats is that they A. Denature as they cool B. Do not have double bonds C. Have double bonds in their carbon chains D. Are polymeric E. Are composed of steroids chains 22. Lipids are composed of A. Nucleotide B. Amino acids C. Monosacharides D. Glycerol and fatty acids E. Nucleosides 23. Which of the following statements is true A. Enzymes increase the activation energy of reactants B. Enzymes lower the activation energy of products C. Enzymes increase the activation energy of products D. Enzymes lower the activation energy of reactants in a chemical reaction E. Enzymes have no action on activation energy 24. Which of the following is true A. A non-competitive inhibitor molecule is quite different in structure from the substrate B. A non- competitive inhibitor molecule is similar in structure from the substrate C. A competitive inhibitor molecule has a different structure to the substrate molecule D. A non- competitive inhibitor interacts only with the product E. A competitive inhibitor interacts only with the product. 25. Which of the following enzymes catalyzes the first step of glycolysis A. Lipase B. Hexokinase C. Fructokinase D. Aldolase E. Pyrurate kinase 26. Which of the following enzymes catalyses the last step of glycolysis A. Lipase B. Hexokinase C. Phosphofructokinase D. Aldolase E. Pyruvate kinase 2013 Technical University of Mombasa Page 5
27. Which one of the following statement is true of gluconeogenesis. A. Is identical to glycolysis but runs in the opposite direction B. Pathway that systhesises glucose C. Sythesizes lipids D. Synthesizes amino acids E. Synthesizes nucleic acids 28. Vitamins are essential to the survival of organisms because vitamins function as A. Nucleic acids B. Substrates C. Co-enzymes D. Nucleotides E. Nucleosides 29. At above OC most enzymes are A. In active B. Active C. Destroyed D. Replicated E. Denatured 30. The enzyme ar classified into A. Five groups B. Three groups C. Six groups D. Four groups E. Eight groups 2013 Technical University of Mombasa Page 6
SECTION B 1. a)outline the steps of the citric acid cycle (10marks) b) Using relevant examples describe the enzyme cofactors (10marks) 2. a) Outlinethe preparation phase of the glycolyte pathway (10marks) b) Using an illustration describe enzyme activation energy (10marks) 2013 Technical University of Mombasa Page 7