MCQOPTIONS
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MCQOPTIONS
This section includes 34 Mcqs, each offering curated multiple-choice questions to sharpen your Biology Mcqs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Biological molecules (proteins) which catalyze a biochemical reaction and remain unchanged after completion of reaction are called |
| A. | Cofactor |
| B. | Coenzymes |
| C. | Activator |
| D. | Enzymes |
| Answer» E. | |
| 2. |
In which of the following location enzymes controlling cellular respiration are present? |
| A. | Nucleus |
| B. | Chlorophast |
| C. | Milochondria |
| D. | Ribosome |
| Answer» D. Ribosome | |
| 3. |
Which statement about enzyme is incorrect: |
| A. | Some of them consist solely of protein with no non protein part. |
| B. | They catalyze a chemical reaction without being utilized. |
| C. | All enzymes are fibrous Proteins. |
| D. | They without their cofactor are called apoenzyme. |
| Answer» D. They without their cofactor are called apoenzyme. | |
| 4. |
An activated enzyme consisting of polypeptide chain and a cofactor is called: |
| A. | Apoenzyme |
| B. | Holoenzyme |
| C. | Activated enzyme |
| D. | Both b and c |
| Answer» E. | |
| 5. |
Which one forms the raw material for coenzymes? |
| A. | Vitamins |
| B. | Carbohydrates |
| C. | Proteins |
| D. | Metals |
| Answer» B. Carbohydrates | |
| 6. |
Enzymes _________ the activation energy of a chemical reaction |
| A. | Increases |
| B. | Decreases |
| C. | Does not effect |
| D. | Increases or decreases depending upon individual enzyme |
| Answer» C. Does not effect | |
| 7. |
The active site of an enzyme: |
| A. | Never changes |
| B. | Forms no chemical bond with substrate |
| C. | Determined by structure and the specificity of the enzyme. |
| D. | They are non specific in their action. |
| Answer» D. They are non specific in their action. | |
| 8. |
Excessive increase in temperature of medium causes the enzyme molecule to |
| A. | Activate |
| B. | Unaffected |
| C. | Denatured |
| D. | None of these. |
| Answer» D. None of these. | |
| 9. |
Extreme change in pH results in: |
| A. | Change in ionization of amino acids at the active site of the enzyme. |
| B. | Change in the ionization of the substrate. |
| C. | Denaturation of the enzyme |
| D. | Increase in the reaction rate. |
| Answer» D. Increase in the reaction rate. | |
| 10. |
Optimal temperature of enzymes present in human body is |
| A. | 27?C |
| B. | 37?C |
| C. | 47?C |
| D. | 30?C |
| Answer» C. 47?C | |
| 11. |
Inhibitors which block the enzyme by forming weak bond are called |
| A. | Competitive inhibitors. |
| B. | Non-competitive inhibitors |
| C. | Irreversible inhibitors. |
| D. | Both a and b |
| Answer» E. | |
| 12. |
A substance which binds at the active site of the enzyme but does not result in the formation of the products is called: |
| A. | Irreversible inhibitor |
| B. | Reversible inhibitor |
| C. | Competitive inhibitor |
| D. | Non-competitive inhibitor |
| Answer» D. Non-competitive inhibitor | |
| 13. |
The structure of an enzyme is altered by: |
| A. | Irreversible inhibitor |
| B. | Reversible inhibitor |
| C. | Competitive inhibitor |
| D. | Non-competitive inhibitor |
| Answer» B. Reversible inhibitor | |
| 14. |
Malonic acid is an example of: |
| A. | Irreversible inhibitor |
| B. | Reversible inhibitor |
| C. | Competitive inhibitor |
| D. | Non-competitive inhibitor |
| Answer» D. Non-competitive inhibitor | |
| 15. |
If enzyme concentration is low than substrate pH and temperature values are equal to requirement then which of the following will increase rate of reaction. |
| A. | Increase in concentration of enzyme |
| B. | Increase in concentration of substrate |
| C. | Increase in pH |
| D. | Increase in temperature |
| Answer» B. Increase in concentration of substrate | |
| 16. |
A three dimensional dcavity bearing a specific charge by which the enzyme reacts with its substrate is called |
| A. | Active site |
| B. | Binding site |
| C. | Catalytic site |
| D. | Allosteric site |
| Answer» B. Binding site | |
| 17. |
Which step causes activation of catalytic site of an enzyme? |
| A. | Change in pH of the surroundings. |
| B. | Formation of Enzyme Susstrate complex. |
| C. | Change in the charge of the active site. |
| D. | Change in temperature |
| Answer» C. Change in the charge of the active site. | |
| 18. |
Lock and Key model was proposed by |
| A. | Emil Fischer |
| B. | Koshland |
| C. | Robin Williams |
| D. | Rudolph Virchow |
| Answer» B. Koshland | |
| 19. |
Which statement is incorrect about Lock and Key Model? |
| A. | Specific enzyme can transform only a specific substrate |
| B. | Active site of an enzyme is a non flexible structure. |
| C. | Active site does not change before during or even after the reaction. |
| D. | It explains the mechanism of every chemical reaction. |
| Answer» E. | |
| 20. |
The rate of reaction is directly proportional to the concentration of an enzyme which statement is incorrect in this respect: |
| A. | Increase in enzyme molecule increases the available active sites. |
| B. | This relation is for unlimited time period with unlimited enzyme concentration |
| C. | If the concentration is doubled the rate will become two fold. |
| D. | None of these. |
| Answer» C. If the concentration is doubled the rate will become two fold. | |
| 21. |
If the concentration of enzyme is kept constant and amount of substrate is increased a point is reached where increase in substrates concentration does not affect the reaction rate because of |
| A. | Enzymes get denatured at higher substrate conc. |
| B. | Rate of reaction is indirectly proportional to substrate concentration at this point. |
| C. | All the active sites on enzyme molecule are occupied. |
| D. | None of these. |
| Answer» D. None of these. | |
| 22. |
If more substrate to already occurring enzymatic reaction is added more enzyme activity is seen because: |
| A. | There is probably more substrate present than there is enzyme. |
| B. | There is probably more enzayme available than there is substrate. |
| C. | There is probably more product present than there is either substrate or enzyme. |
| D. | The enzyme substrate complex is probably failing to form during the reaction. |
| Answer» C. There is probably more product present than there is either substrate or enzyme. | |
| 23. |
If more substrate to already occurring enzymatic reaction is added and there is no effect on the rate of the reaction what is the form given to this situation: |
| A. | Saturation |
| B. | Denaturation |
| C. | Composition |
| D. | Inhibition |
| Answer» B. Denaturation | |
| 24. |
During rest the breathing occurs rhythmically at the frequency of ______ times per minute in human |
| A. | 16-30 |
| B. | 15-20 |
| C. | 5?10 |
| D. | 6?12 |
| Answer» C. 5?10 | |
| 25. |
The maximum amount of oxygen which normal human blood absorbs and carries at sea level is _____ per 100 ml of blood. |
| A. | 10 ml |
| B. | 20 ml |
| C. | 30 ml |
| D. | 40 ml |
| Answer» C. 30 ml | |
| 26. |
Haemoglobin can be almost completely oxygenated by an oxygen pressure of ____ of mercury. |
| A. | 10 mm |
| B. | 60 mm |
| C. | 10 cm |
| D. | 100mm |
| Answer» E. | |
| 27. |
The increase in pH of blood has _____ effect on the oxygen carrying capacity of haemogolobin |
| A. | Plus ve |
| B. | ? ve |
| C. | No |
| D. | All of these |
| Answer» B. ? ve | |
| 28. |
Arterial blood contains ______ of CO2 per 100 ml of blood |
| A. | 54 ml |
| B. | 60 ml |
| C. | 64 ml |
| D. | 50 ml |
| Answer» E. | |
| 29. |
% age of CO2 carried as carboxyhaemoglobin is |
| A. | 5% |
| B. | 70% |
| C. | 20% |
| D. | 10% |
| Answer» D. 10% | |
| 30. |
More than ______ compounds of tar of tobacco smoke are involved to cause cancer |
| A. | 5 |
| B. | 90 |
| C. | 15 |
| D. | 10 |
| Answer» E. | |
| 31. |
A disease of longs in which inside of the lungs is damaged resulting in cough and fever |
| A. | Lung cancer |
| B. | Asthma |
| C. | Emphysema |
| D. | Pulmonary tuberculosis |
| Answer» D. Pulmonary tuberculosis | |
| 32. |
Voice box is another name used for |
| A. | Buccal cavity |
| B. | Pharynx |
| C. | Larynx |
| D. | Chest Cavity |
| Answer» D. Chest Cavity | |
| 33. |
Respiratory distress syndrome is common especially for infants with a |
| A. | Less than 7 month |
| B. | Less than 8 month |
| C. | Less than 9 month |
| D. | More than 9 month |
| Answer» B. Less than 8 month | |
| 34. |
All of the following contain cartilage except |
| A. | Larynx |
| B. | Trachea |
| C. | Bronchi |
| D. | Bronchioles |
| Answer» E. | |