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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461. According to_model, the active site of enzyme is modified as the substrate interacts with enzyme.
- A. Induced fit
- B. Emil Fischer
- C. Lock and key
- D. Fluid mosaic
Explanation: According to the induced fit model, the active site of the enzyme undergoes a conformational change or modification as the substrate…
Correct answer: Induced fit- A. Koshland
- B. Fischer
- C. Watson
- D. Rosalind Franklin
Explanation: A modified form of the lock and key model is called the induced fit model, which was proposed by Koshland.
Correct answer: Koshland- A. Lock
- B. Key
- C. Can act as both
- D. None
Explanation: According to the Lock and Key model, enzymes are likened to a lock that only fits a specific key, which in this case is the substrate.
Correct answer: Lock- A. Induce fit model
- B. Lock and key
- C. Both models
- D. None
Explanation: The lock and key model is the correct explanation for the working of sucrase and maltase.
Correct answer: Lock and key465. With the increase of enzyme concentration in a reaction, more_is/are available for the substrate.
- A. Binding sites
- B. Products
- C. Active sites
- D. Activation energy
Explanation: Increasing the concentration of enzymes in a reaction amplifies the number of available active sites.
Correct answer: Active sites- A. Non-competitive inhibitors
- B. Allosteric inhibition
- C. Competitive inhibitors
- D. Irreversible inhibition
Explanation: The correct answer is Non-competitive inhibitors. These inhibitors bind to an enzyme at a site other than the active site, causing a…
Correct answer: Non-competitive inhibitors- A. Non-competitive reversible
- B. Irreversible
- C. Competitive reversible
- D. None of these
Explanation: Competitive inhibitors are substances that compete with the substrate for binding to the active site of the enzyme.
Correct answer: Competitive reversible- A. Transferases
- B. Lyases
- C. Oxidoreductases
- D. Hydrolases
Explanation: Oxidoreductases are specialized enzymes that facilitate oxidation and reduction reactions by transferring electrons or hydrogen ions…
Correct answer: Oxidoreductases- A. 5°C to 10°C
- B. 10°C to 15°C
- C. 18°C to 28°C
- D. 25°C to 37°C
Explanation: Most enzymes function best within the temperature range of 25°C to 37°C.
Correct answer: 25°C to 37°C- A. 37 degree celsius
- B. 49 degree celsius
- C. 25 degree celsius
- D. 10 degree celsius
Explanation: Optimum body temprature for the enzyme to act at a maximum rate for human body is 37°.
Correct answer: 37 degree celsius- A. Irreversible inhibitors
- B. Reversible inhibitors
- C. Competitive inhibitors
- D. Non competitive inhibitor
Explanation: Irreversible inhibitors bind to active site and form covalent bonds.
Correct answer: Irreversible inhibitors- A. 7.60
- B. 8.00
- C. 9.00
- D. 9.70
Explanation: Pancreatic enzymes mostly work in an alkaline pH which helps in the digestion of food in small intestine.
Correct answer: 9.00- A. The substrate binds with the enzyme at its active site
- B. The addition of a lot of succinates does not reverse the inhibition of succinic dehydrogenase by malonate
- C. A noncompetitive inhibitor binds the enzyme at a site distinct from that which binds the substrate
- D. Malonate is a competitive inhibitor of succinic dehydrogenase
Explanation: The reduction of activity of succinate dehydrogenase by malonate is an example of competitive inhibition.
Correct answer: The addition of a lot of succinates does not reverse the inhibition of succinic dehydrogenase by malonate- A. Thermoacidophiles
- B. Thermophiles
- C. Acidophiles
- D. Alkaliphiles
Explanation: Modern detergents contain enzyme preparation of alkaline proteases which are called alkaliphiles. These help in removing protein stains.
Correct answer: Alkaliphiles- A. Plasma membrane
- B. Chloroplast
- C. Mitochondria
- D. Nucleolus
Explanation: Fatty acid metabolism is the function of mitochondria, while synthesis of lipids is the function of SER.
Correct answer: Mitochondria- A. Activator
- B. Prosthetic group
- C. Coenzyme
- D. Apo-enzyme
Explanation: A prosthetic group is a non-polypeptide unit tightly and permanently bound to an enzyme, contributing to its function.
Correct answer: Prosthetic group- A. Coenzyme
- B. Prosthetic group
- C. Activator
- D. Apoenzyme
Explanation: Inorganic ions often function as activators for enzymes. They assist enzymes in their catalytic activity.
Correct answer: Activator- A. Extra factor
- B. Efficient co-factor
- C. Additional factor
- D. co-factor
Explanation: A co-factor is a non-protein molecule required for the proper functioning of enzymes.
Correct answer: co-factor- A. Koshland
- B. Watson
- C. Fischer
- D. Rosalind Franklin
Explanation: Daniel Koshland, in 1958, proposed modified form of Lock and Key model, which is known as "Induced Fit Model".
Correct answer: Koshland- A. Lock
- B. Key
- C. Can act as both
- D. None
Explanation: According to the Lock and Key model, enzymes act as a "key" that specifically fits the "lock" (substrate) to catalyze a chemical reaction.
Correct answer: Lock