MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of the following is not a part of Kreb's cycle |
| A. | Dehydrogenation |
| B. | Acetylation |
| C. | Oxidative phosphorylation |
| D. | Decarboxylation |
| Answer» D. Decarboxylation | |
| 2. |
A molecule of ATP is formed when electron passes from |
| A. | Cyt c to Cyt a |
| B. | Cyt a to Cyt c |
| C. | Cyt b to Cyt c |
| D. | Cyt c to Cyt b |
| Answer» C. Cyt b to Cyt c | |
| 3. |
How many molecules of ATP are produced per molecule of\[FAD{{H}_{2}}\]oxidised |
| A. | One |
| B. | Two |
| C. | Three |
| D. | Four |
| Answer» C. Three | |
| 4. |
Between which of the following stages GTP is formed by substrate level phosphorylation |
| A. | Succinate to fumarate |
| B. | Ketoglutarate to succinate |
| C. | Oxalosuccinate to glutarate |
| D. | Fumarate to malate |
| Answer» C. Oxalosuccinate to glutarate | |
| 5. |
The process by which the energy of glucose is released under aerobic respiration was discovered by |
| A. | Hopkins |
| B. | Lister |
| C. | Kreb's |
| D. | Pasteur |
| Answer» D. Pasteur | |
| 6. |
Kreb's has been awarded Nobel Prize in 1953 for explaining |
| A. | Energy forming process in the cell |
| B. | ATP metabolism |
| C. | Respiration chain |
| D. | Oxidation of cytoplasm |
| Answer» B. ATP metabolism | |
| 7. |
Enzymes were discovered for the first time in [Pb. PMT 1995] |
| A. | Yeast |
| B. | Maize |
| C. | Bacteria |
| D. | Algae |
| Answer» B. Maize | |
| 8. |
Which enzyme shows greatest substrate specificity [CPMT 2005] |
| A. | Nuclease |
| B. | Trypsin |
| C. | Sucrase |
| D. | Pepsin |
| Answer» D. Pepsin | |
| 9. |
The permeases are [MP PMT 2003] |
| A. | Structural membrane proteins |
| B. | Enzymatic membrane proteins |
| C. | Carrier membrane proteins |
| D. | None of these |
| Answer» D. None of these | |
| 10. |
Which of the following enzyme can form RNA from DNA [MP PMT 1992] |
| A. | Restriction enzyme |
| B. | DNA polymerase |
| C. | RNA polymerase |
| D. | Reverse transcriptase |
| Answer» D. Reverse transcriptase | |
| 11. |
Lactose operon is considered to be glucose sensitive due to [DPMT 2003] |
| A. | Catabolite induction |
| B. | Allosteric inhibition |
| C. | Anabolic inhibition |
| D. | None of these |
| Answer» B. Allosteric inhibition | |
| 12. |
Decline in the activity of the enzyme hexokinase by glucose 6 - phosphate is caused by [Kerala CET (Med.) 2003] |
| A. | Non-competitive |
| B. | Competitive inhibitions |
| C. | Allosteric modulator |
| D. | Denaturation of enzymes |
| Answer» D. Denaturation of enzymes | |
| 13. |
During glycolysis enzyme hexokinase changes glucose to glucose-6- phosphate. Glucose-6-phosphate is inhibited by [CBSE PMT 1996] |
| A. | Feedback inhibition |
| B. | Positive feedback |
| C. | Competitive inhibition |
| D. | Non-competitive inhibition |
| Answer» B. Positive feedback | |
| 14. |
Non-competitive inhibitors alter |
| A. | Structure of enzyme |
| B. | Structure of active site |
| C. | Velocity of enzymatic reaction |
| D. | All the above |
| Answer» E. | |
| 15. |
Metabolic poisons which alter the structure of an apoenzyme are |
| A. | Competitive inhibitors |
| B. | Substrate analogs |
| C. | Product inhibitors |
| D. | Non-competitive inhibitors |
| Answer» E. | |
| 16. |
Enzyme can be made functionless by |
| A. | Removing its product as fast as it is formed |
| B. | Doubling its concentration |
| C. | Decreasing its concentration |
| D. | Blocking its active site |
| Answer» E. | |
| 17. |
Who demonstrated that alcoholic fermentation was an enzymatic process |
| A. | Louis Pasteur |
| B. | Justus Liebeg |
| C. | Edward Buchner |
| D. | James Sumner |
| Answer» D. James Sumner | |
| 18. |
Competitive inhibitors (like malonate) alter |
| A. | Velocity of reaction |
| B. | Value of Km (Michelis constant) |
| C. | Active site |
| D. | Structure of enzyme |
| Answer» C. Active site | |
| 19. |
Inhibitory effect of melonic acid on succinic dehydrogenase enzyme is [AIIMS 2003] |
| A. | Competitive inhibition |
| B. | Non-competitive inhibition |
| C. | Feedback inhibition |
| D. | Inhibition due to end product |
| Answer» B. Non-competitive inhibition | |
| 20. |
Enzyme inhibition caused by a substrate analogue is |
| A. | Competitive |
| B. | Non-competitive |
| C. | Incompetitive |
| D. | Semi-competitive |
| Answer» B. Non-competitive | |
| 21. |
Number of active sites in allosteric enzyme is [CPMT 2000] |
| A. | One |
| B. | Two |
| C. | Three |
| D. | Four |
| Answer» C. Three | |
| 22. |
When an enzyme induced product inhibits enzymatic activity, inhibition is called |
| A. | Competitive inhibition |
| B. | Non-competitive inhibition |
| C. | Feedback inhibition |
| D. | None of the above |
| Answer» D. None of the above | |
| 23. |
Jacob and Monad named those enzymes allosteric whose activity is regulated by |
| A. | Substrate |
| B. | End product |
| C. | Coenzymes |
| D. | Prosthetic groups |
| Answer» C. Coenzymes | |
| 24. |
Template theory of enzyme action is supported by [BVP 2003] |
| A. | Enzymes occur in living beings and speed up certain reactions |
| B. | Enzymes speed up reaction |
| C. | Enzymes determine the direction of reaction |
| D. | Compounds similar to substrate inhibit enemy activity |
| Answer» E. | |
| 25. |
Who proposed the principal of "Induced fit" [BHU 1998] |
| A. | Jacob |
| B. | Fischer |
| C. | Koshland |
| D. | Laderberg |
| Answer» D. Laderberg | |
| 26. |
To explain the mechanism of enzymatic action, who proposed "Lock and key hypothesis'' [CPMT 1996; MP PMT 1998; BHU 2000; RPMT 2002] |
| A. | Fischer |
| B. | Jacob |
| C. | Koshland |
| D. | Sumner |
| Answer» B. Jacob | |
| 27. |
Which of the following is called "biological middle man'' |
| A. | Hormone |
| B. | Vitamin |
| C. | Enzyme |
| D. | All the above |
| Answer» D. All the above | |
| 28. |
The cause of specificity of an enzyme is |
| A. | Its prosthetic group |
| B. | Sequence of amino acid in its primary structure |
| C. | Its secondary structure |
| D. | Its tertiary structure and coenzymes |
| Answer» C. Its secondary structure | |
| 29. |
Which one value is required for better enzymatic action [BHU 1995, 2000] |
| A. | High Ki |
| B. | Low Ki |
| C. | Low Km |
| D. | High Km |
| Answer» C. Low Km | |
| 30. |
Enzymes as they exist inside the cell are [MP PMT 1993] |
| A. | In solid form |
| B. | In crystalline form |
| C. | In colloidal form |
| D. | In solution form |
| Answer» D. In solution form | |
| 31. |
DNA polymerase enzyme is responsible for the synthesis of |
| A. | DNA from RNA |
| B. | DNA from DNA |
| C. | RNA from DNA |
| D. | RNA from RNA |
| Answer» C. RNA from DNA | |
| 32. |
Many of the hydrolytic reactions are [BHU 2001] |
| A. | Reversible |
| B. | Irreversible |
| C. | Endothermic |
| D. | Exothermic |
| Answer» B. Irreversible | |
| 33. |
Which is not true for enzymes [AMU 2005] |
| A. | Enzyme is a complex structure of protein |
| B. | Enzyme can be regulated by specific molecules |
| C. | Enzyme is more sensitive for the changes of temperature and pH |
| D. | Enzyme functions as catalyst for various reactions |
| Answer» E. | |
| 34. |
Which one of the following statements regarding enzyme inhibition is correct [CBSE PMT 2005] |
| A. | Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein |
| B. | Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme |
| C. | Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate |
| D. | Non-competitive inhibitors often bind to the enzyme irreversibly |
| Answer» C. Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate | |
| 35. |
Telomerase is an enzyme which is a [AIIMS 2005] |
| A. | Simple protein |
| B. | RNA |
| C. | Ribonucleoprotein |
| D. | Repetitive DNA |
| Answer» D. Repetitive DNA | |
| 36. |
In which one of the following enzymes, is copper necessarily associated as an activator [CBSE PMT 2004] |
| A. | Lactic dehydrogenase |
| B. | Tyrosinase |
| C. | Carbonic anhydrase |
| D. | Trytophanase |
| Answer» C. Carbonic anhydrase | |
| 37. |
Which one of the following enzyme contains Mo as prosthetic group |
| A. | Phosphatase |
| B. | Dehydrogenase |
| C. | Isomerase |
| D. | Nitrate reductase |
| Answer» E. | |
| 38. |
Which one of the following enzyme contains Mn metallic ion as the prosthetic group [BHU 2000] |
| A. | Phosphatase |
| B. | Dehydrogenase |
| C. | Peptidase |
| D. | Catalase |
| Answer» D. Catalase | |
| 39. |
Which of the following element inhibits the activity of sulphydryl enzyme |
| A. | Fe |
| B. | Cu |
| C. | Zn |
| D. | Pb |
| Answer» E. | |
| 40. |
Cytochrome oxidase enzyme contains |
| A. | Magnesium |
| B. | Manganese |
| C. | Iron |
| D. | Cobalt |
| Answer» D. Cobalt | |
| 41. |
The prosthetic group (metallic cofactor) of various respiratory enzymes is |
| A. | Ca |
| B. | Fe |
| C. | Mg |
| D. | Mo |
| Answer» D. Mo | |
| 42. |
Which mineral element is essential for the activity of enolase enzyme |
| A. | Copper |
| B. | Cobalt |
| C. | Zinc |
| D. | Boron |
| Answer» E. | |
| 43. |
Which one of the following is a coenzyme |
| A. | Nicotinamide |
| B. | Riboflavin |
| C. | Pantothenic acid |
| D. | All the above |
| Answer» E. | |
| 44. |
Which mineral element is essential for the activity of aconitase enzyme |
| A. | Magnesium |
| B. | Manganese |
| C. | Calcium |
| D. | Iron |
| Answer» E. | |
| 45. |
Which of the following is a loosely bound coenzyme |
| A. | Cu |
| B. | Mn |
| C. | Zn |
| D. | Vitamin\[{{B}_{12}}\] |
| Answer» E. | |
| 46. |
Who got the Nobel prize working on enzymes in the year 1978 [MP PMT 1997] |
| A. | W. Arber and D. Nathans |
| B. | Nass and Nass |
| C. | R. Misra |
| D. | H.G. Khorana |
| Answer» B. Nass and Nass | |
| 47. |
Which of the following is not a co-enzyme [CPMT 2004] |
| A. | NAD |
| B. | NADP |
| C. | FAD |
| D. | ATP |
| Answer» E. | |
| 48. |
NADP is [BHU 1984] |
| A. | A coenzyme |
| B. | A part of tRNA |
| C. | An enzyme |
| D. | A part of rRNA |
| Answer» B. A part of tRNA | |
| 49. |
FAD or FMN is a coenzyme. Which vitamin is incorporated into its structure [BHU 1987] |
| A. | Vitamin C |
| B. | Vitamin B1 |
| C. | Vitamin B6 |
| D. | Vitamin B2 (Riboflavin) |
| Answer» E. | |
| 50. |
Substances which enhance reactions after combining with enzymes are called |
| A. | Prosthetic groups |
| B. | Coenzymes |
| C. | Inducers |
| D. | Inhibitors |
| Answer» D. Inhibitors | |