Mcq 2 enzymes
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Mcq 2 enzymes

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Mcq 2 enzymes Mcq 2 enzymes Document Transcript

  • Enzyme1. Group of organic catalysts, protein in nature, present inside the living cellsa- Enzymesb- Catalystsc- Hormonesd- None of the above2. All of the following is true regarding enzymes except …..a- Heat labileb- Colloidalc- Dialyzabled- High molecular weight3. Organic substance on which the enzyme acts …….a- Substrateb- Co-Enzymec- Productd- None of the above4. All of the following can be considered as a co Enzyme for transfer of H excepta- Biotinb- ATPc- FADd- Folic acid5. One of the following can be considered as a co Enzyme for transfer of groups other than H excepta- Biotinb- ATPc- FADd- Folic acid 1 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme6. One of the following is considered a feature of Enzymes except ……a- Globular Proteinsb- Undergo Denaturationc- Simple Proteinsd- Non-Specific7. Enzyme acts on a special type of bond at specific site and attached to specific groups ……a- Group Specificityb- Absolute Specificityc- Relative Specificityd- Optical Specificity8. D-amino acid Oxidase represents ……a- Group Specificityb- Absolute Specificityc- Relative Specificityd- Optical Specificity9. Pancreatic Lipase represents …….a- Group Specificityb- Absolute Specificityc- Relative Specificityd- Optical Specificity10. Special sequence of amino acids in the protein molecule of the enzyme to which the substrate isattached…….a- Catalytic Siteb- Active sitec- Allosteric Sited- None of the above 2 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme11. All sequences of amino acids which affect the activity of the enzyme ……a- Catalytic Siteb- Active sitec- Allosteric Sited- All of the above12. Substrate induces a conformational change in the catalytic site …….a- Lock and key modelb- Flexible model of catalytic sitec- Rigid model of catalytic sited- None of the above13. Concentration of the product increases directly by time …….a- Maximum Velocityb- End velocityc- Initial Velocityd- None of the above14. Increase in substrate concentration leads to ……..a- Increase of velocityb- Increase in enzyme activityc- Increase of V maxd- All of the above15. Substrate concentration which produces half maximal velocity (½Vmax.) ……….a- Full Concentrationb- Null Concentrationc- Michael’s Concentrationd- All of the above 3 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme16. Increase in enzyme concentration ……. the rate of reactiona- Increaseb- Decreasec- No effectd- Permissive effect17. Complete irreversible loss of enzyme activity occurs at ……a- 37 degree Cb- 45 degree Cc- 0 degree Cd- 60-65 degree C18. Temperature at which the enzymatic reaction velocity is maximal ……a- Optimum Temperatureb- 37 degree Cc- 65 degree Cd- A and b togethere- None of the above19. Optimum PH for Trypsin is ……a- 6.8b- 8.4c- 8d- 220. Optimum PH for Alkaline Phosphatasea- 6.8b- 8.4c- 8d- 2 4 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme21. All of the following inhibits enzymatic activity excepta- Physical Agentsb- Heatingc- Shakingd- Red and Blue lights22. Pepsin is activated through ……..a- Removal of inhibitory peptideb- Reducing agentc- Mineralsd- Allosteric activators23. Glyceraldehyde 3-P dehydrogenase is activated through …..a- Removal of inhibitory peptideb- Reducing agentc- Mineralsd- Allosteric activators24. Metaloenzymes is activated through …..a- Removal of inhibitory peptideb- Reducing agentc- Mineralsd- Allosteric activators25. Tyrosinase requires ……a- ZN ++b- CU ++c- CL –d- MG ++ 5 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme26. Phosphofructokinase enzyme is activated through …..a- Removal of inhibitory peptideb- Reducing agentc- Mineralsd- Allosteric activators27. Activation by Phosphorylation excludes one of the following …….a- Hormone sensitive lipaseb- Glycogen Phosphyrlasec- Glycogen Synthetased- None of the above28. Competitive inhibition includes all of the following excepta- Chemical structure of the inhibitor closely resembles that of the substrate.b- Combines Reversibly with the enzymec- When both the substrate and the inhibitor are present they compete for the same binding site.d- V max is decreasede- Is removed by increases the concentration of inhibitor29. Reversible noncompetitive Inhibition includes all of the following excepta- I combine with the enzyme away from the catalytic site.b- The I is not similar to the substrate in structure.c- The I can combine with the free enzyme or with the enzyme substrated- increase the Km30. Phosphoglyceraldehyde dehydrogenase Resembles …….a- Reversible Non Competitive Inhibitionb- Irreversible noncompetitive Inhibitionc- Allosteric inhibitiond- Competitive inhibition 6 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme31. Increased product concentration …… the enzyme activitya- Increasesb- Decreasesc- No effectd- Permissive effect32. Substances which stimulate gene expression into protein …….a- Inducerb- Suppressorc- Repressorsd- Co-Enzymes33. Concerning Isoenzymes …….a- Have quaternary structure and the individual subunits in each isoenzyme are different from the othersb- They act on the different substrate and will give the same productc- They have different affinity to the substrate.d- They are present in different tissues.34. HMMM is present in ……..a- Heartb- Kidneyc- Liverd- Muscles35. HHMM is present ina- Kidneyb- Musclesc- Heartd- None of the above 7 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme36. Non Functional plasma enzymes include all of the following except …..a- Transaminases ( AST & ALT )b- Alkaline Phosphatasec- Lipoprotein lipased- None of the above37. Increased in bone metastasis ………a- Alkaline phosphataseb- Creatine kinasec- LDHd- None of the above38. Increased in Prostatic Carcinoma ………a- Alkaline phosphataseb- Creatine kinasec- LDHd- None of the above39. Decreased in Galactosemia ………a- Streptokinaseb- Digestive enzymesc- Galactosyl transferased- α-chymotrypsin40. Treatment of intraocular hemorrhage is done bya- Streptokinaseb- Digestive enzymesc- LDHd- α-chymotrypsin 8 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme41. The oxidation process occurs by ………a- Addition of oxygen.b- Removal of hydrogen.c- Loss of electrond- All of the above42. Redoxes that use oxygen as a hydrogen receptor are called ……..a- Oxidasesb- Hyper peroxidasesc- Dehydrogenasesd- Oxygenases43. Catalase is specifically abundant in all of the following except ……..a- Liverb- Kidneyc- Erythrocytesd- Milk and leucocytes44. Enzymes utilizing H2O2 as substrate ……….a- Oxidasesb- Hyper peroxidasesc- Dehydrogenasesd- Oxygenases45. LDH depends on ………. In dehydrogenationa- Nicotinamideb- FADc- C.AMPd- None of the above 9 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme46. Enzymes which catalyze transfer of functional groups (G) other than hydrogen between a pair ofsubstrates …….a- Transferaseb- Oxygenasesc- Dehydrogenasesd- Hydrolases47. All of the following are included in Transferase class of enzymes except …….a- Transaminaseb- Hydrolasec- Transglycosayld- None of the above48. Split terminal peptide linkage splitting one amino acid at a time is ……..a- Estrasesb- Endoeptidasesc- Exopeptidasesd- Glycosidases49. Fumerase is an example of …….a- Transferaseb- Hydrolasec- Oxidased- Lyases50. Lipase is an example of …….a- Transferaseb- Estrasesc- Oxidasesd- Lyases 10 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme51. Enzymes link two molecules using energy from ATP ……a- Lyasesb- Hydrolasec- Ligased- Redox52. Carboxylase is an example of …….a- Transferaseb- Estrasesc- Oxidasesd- LigasesChoose (A) for true and (B) For false of the following53. Pepsin acts on peptide bonds between amino groups of aromatic amino acid and carboxylic group ofanother amino acid (A)54. Enzymes are usually specific in action (A)55. In Absolute specificity the enzyme acts at different rates on one type of bond inCompounds chemically related (B)56. Enzymes may be considered to lower energy barriers for chemical reactions (A)57. Increase in the substrate concentration will lead to decrease in enzyme activity58. Increase in enzyme concentration increase the rate of reaction (A)59. Some enzymes containing SH groups requires Minerals to be activated (B)60. In Competitive inhibition Vmax of the enzyme is not decreased (A)61. Inducers are substances which inhibit gene expression (B)62. Isoenzyme is oligomeric enzyme (A) 11 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme1: What is a cofactor?(A) Inorganic ions(B) Organic molecules(C) Both a and b(D) None of the above2: Mg+2 is an inorganic activator for the enzyme(A) Phosophatase(B) Carbonic anhydrase(C) Enterokinase(D) Amylase3: Zn+2 is an inorganic activator for enzyme.(A) Carbonic anhydrase(B) Phosophatase(C) Chymotrypsin(D) Maltase4: Which antibiotic blocks the active site of an enzyme that many bacteria used to make cell-walls?(A) Amphotericin(B) Gentamicin(C) Penicillin(D) Cephalosporin 12 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme5: DDT and Parathion are inhibitors of key enzymes in(A) Nervous system(B) Respiratory system(C) Digestive system(D) Circulatory system6: 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 enzymes7: Which of the following enzymes would digest a fat?(A) sucrase(B) protease(C) Ligase(D) lipase8: In the Lock and Key model of enzyme action, the part of the enzyme that recognizes thesubstrate is known as the(A) Enzyme-substrate complex(B) Product(C) Enzyme-product complex(D) Active site 13 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com
  • Enzyme9: Which model of enzyme action is represented in this diagram.(A) Fluid mosaic model(B) Induce fit model(C) Lock and key model(D) Reflective index model10: A certain enzyme will hydrolyze egg white but not starch. Which statement best explainsthis observation?(A) Starch molecules are too large to be hydrolyzed(B) Enzyme molecules are specific in their actions(C) Egg white acts as a coenzyme for hydrolysis(D) Starch is composed of amino acids. 14 Dr. Ehab Aboueladab, Associate Prof.Dr. Of Biochemistry and Nutrition, email:ehab10f@gmail.com