Free Enzymes MCQs with Answers
633 Enzymes MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Enzymes are biological catalysts that lower activation energy without being consumed, and their specificity is explained by the lock and key and induced fit models. Work includes the effects of temperature, pH and substrate concentration on reaction rate, plus competitive and non-competitive inhibition and how these differ.
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Read the Enzymes notesFree MDCAT chapter notes with key terms633 questions · page 26 of 32
- A. Amylase
- B. Apoenzyme
- C. Holoenzyme
- D. Coenzyme
Explanation: If the non-protein part is loosely attached to the protein part of the enzyme, it is known as coenzyme.
Correct answer: Holoenzyme- A. Prosthetic Group
- B. Co-Factor
- C. Coenzyme
- D. Activator
Explanation: Some enzymes consist solely of proteins. Others also have a non-protein part known as a cofactor.
Correct answer: Prosthetic Group- A. Irreversible inhibition
- B. Competitive inhibition
- C. Non-competitive and reversible inhibition
- D. Reversible inhibition
Explanation: Non-competitive reversible inhibitor block allosteric site of enzyme, while competitive inhibitors have structural similarity with…
Correct answer: Non-competitive and reversible inhibition504. The following reaction occurs in the human alimentary canal. What is the enzyme and the product?
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Amylase is an enzyme that plays a crucial role in the digestion of carbohydrates, specifically starch, in the alimentary canal (digestive…
Correct answer: Option C- A. Holoenzyme
- B. Apoenzyme
- C. Coenzyme
- D. Zymoenzyme
Explanation: An enzyme devoid of the necessary non-protein molecule for its catalytic activity is often referred to as an "apoenzyme." The non-protein…
Correct answer: Apoenzyme- A. 8.00
- B. 9.00
- C. 7.40
- D. 9.20
Explanation: The optimal pH for pancreatic lipase activity is 9.00. Pancreatic lipase is an enzyme that breaks down triglycerides into fatty acids and…
Correct answer: 9.00- A. Coenzyme
- B. Apoenzyme
- C. Holoenzyme
- D. Proenzyme
Explanation: An enzyme without its cofactor is often referred to as the "apoenzyme." The apoenzyme is the protein component of an enzyme that lacks the…
Correct answer: Apoenzyme- A. 9
- B. 9.3
- C. 9.7
- D. 10
Explanation: The optimum pH of arginase is typically around 9.5-10.5. Arginase is an enzyme that catalyzes the hydrolysis of arginine to ornithine and…
Correct answer: 9.7- A. Active site
- B. Binding site
- C. Catalytic site
- D. Allosteric site
Explanation: Option A: Active site is a groove or a depression on the surface of a substrate into which the enzyme fits.
Correct answer: Active site- A. Proteins
- B. Vitamins
- C. Lipids
- D. Both A and B
Explanation: Option: B Vitamins are the essential raw materials for the synthesis of coenzymes. Coenzymes are closely related to vitamins. (Fact)
Correct answer: Vitamins- A. Coenzyme
- B. Holoenzyme
- C. Cofactor
- D. Apoenzyme
Explanation: If the non-protien part is loosely attached to the protein part in the enzyme, it forms a coenzyme.
Correct answer: Coenzyme- A. 8
- B. 9
- C. 7
- D. 6
Explanation: B is correct because In vitro, pancreatic lipase exhibits the maximum activity at pH 7.5-8.5 (Borgstrom et al., 1957), whereas in vivo, it…
Correct answer: 9- A. Coenzyme
- B. Cofactor
- C. DNA
- D. RNA
Explanation: A cofactor is a non- protein chemical compound that is bound to a protein and is required for the protein's biological activity.
Correct answer: Cofactor- A. High
- B. Low
- C. Remains same
- D. None of these
Explanation: Option B is correct as less activation energy means less energy is supplied for reaction to take place, less time required so rate…
Correct answer: Low- A. substrate
- B. inhibitors
- C. catalyst
- D. both A and B
Explanation: In competitive inhibition, both substrate and inhibitor are competing for binding to the active site.
Correct answer: both A and B- A. Substrate
- B. Coenzyme
- C. Apoenzyme
- D. Holoenzyme
Explanation: An activated enzyme made of a polypeptide chain and a cofactor is called a holoenzyme.
Correct answer: Holoenzyme- A. Substrates must bind the enzyme's active site in order to initiate its effects
- B. Enzymes increase both the forward rate and reverse rate of reaction
- C. Enzymes are not destroyed in a reaction and can be used in the same reaction countless times
- D. Enzymes increase the energy of product created in a reaction
Explanation: Option D is correct since enzymes do not affect the energy of product or reactants(yield).
Correct answer: Enzymes increase the energy of product created in a reaction- A. Concentration of enzyme
- B. Concentration of substrate
- C. Concentration of ES complex
- D. Concentration of inhibitor
Explanation: Non-competetive inhibition is when the inhibitor binds to the enzyme, so the extent of inhibition only depends on the concentration of…
Correct answer: Concentration of inhibitor- A. Change in pH of the surroundings
- B. Change in the charge of the active site
- C. Change in temperature
- D. Formation of enzyme substrate complex
Explanation: The formation of the enzyme-substrate complex is the step that typically leads to the activation of the catalytic site of an enzyme.
Correct answer: Formation of enzyme substrate complex- A. Shape of substrate
- B. Shape of inhibitor
- C. Shape of enzyme
- D. None of these options are correct
Explanation: The allosteric effect in mixed inhibition, alters the shape of enzyme so no substrate can bind to an ultimately no activity can be carried…
Correct answer: Shape of enzyme