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 18 of 32
- A. Stop
- B. Be slowed down
- C. Not affected
- D. Carried out at faster rate
Explanation: The biological processes that occur within all living organisms are chemical reactions, and enzymes regulate most of the reactions.
Correct answer: Be slowed down- A. Prosthetic group
- B. Coenzyme
- C. Activator
- D. Inhibitor
Explanation: Mg+2 serves as an activator that binds to the enzyme, facilitating its interaction with the substrate and promoting catalytic activity.
Correct answer: Activator- A. Amylopsin
- B. Bam H1
- C. Arginase
- D. Peptidyl transferase
Explanation: Peptidyl transferase is an enzyme that is not a protein in nature. It is a ribozyme, a catalytic RNA molecule found in the ribosome.
Correct answer: Peptidyl transferase- A. Mouth
- B. Testes
- C. Large intestine
- D. Stomach
Explanation: Enzymes in the testes require a temperature lower than 37 °C for proper function.
Correct answer: Testes- A. Irreversible inhibition
- B. Feedback inhibition
- C. Reversible inhibition
- D. Non-Reversible inhibition
Explanation: Both competitive and non-competitive inhibition are types of reversible inhibition.
Correct answer: Reversible inhibition- A. Substrate
- B. Enzymes
- C. End product
- D. Temperature
Explanation: The correct answer is the end product, as it plays a key role in feedback inhibition by binding to an allosteric site on an enzyme…
Correct answer: End product- A. Enzyme did not function
- B. Feedback due to the accumulation of the end product
- C. Enzyme was more than substrate's active sites
- D. substrate did not function
Explanation: The addition of more substrate initially increased the rate of the reaction.
Correct answer: Feedback due to the accumulation of the end product- A. Competitive inhibition
- B. Noncompetitive inhibition
- C. Feedback inhibition
- D. Radiation effect
Explanation: Option B should be non competitive inhibition instead of incompetitive inhibition.Option A: Competitive inhibition: Many antibiotic are…
Correct answer: Competitive inhibition- A. Accelerator
- B. Inhibitor
- C. Coenzyme
- D. Activator
Explanation: Inhibitors are substances that react with enzyme in place of substrate but are not converted into product.
Correct answer: Inhibitor- A. Enzymes are unbiased for the substrate.
- B. Enzymes can modify their active sites.
- C. Enzymes are restricted to one reaction type.
- D. An enzyme can catalyze a variety of reactions.
Explanation: Emil Fischer (1890) proposed a Lock and Key model to visualize substrate and enzyme interaction.
Correct answer: Enzymes are restricted to one reaction type.- A. Kinetic energy
- B. Heat energy
- C. Activation energy
- D. Potential energy
Explanation: An enzyme binds to its specific substrate at its active site and facilitates the conversion of substrates into products.
Correct answer: Activation energy- A. Activator
- B. Prosthetic group
- C. Co-enzyme
- D. Apoenzyme
Explanation: Activator is non-protein, but inorganic, detachable co-factor. Activator includes metal ions such as Mg2+ and Fe2+.
Correct answer: Activator- A. Chymotrypsin
- B. Pepsin
- C. Trypsin
- D. Erypsin
Explanation: Pepsin is an enzyme that is secreted in an inactive form known as pepsinogen.
Correct answer: Erypsin- A. Urease
- B. Hexokinase
- C. Maltase
- D. Sucrase
Explanation: Hexokinase is a regulatory enzyme in various metabolic pathways, including glycolysis.
Correct answer: Hexokinase- A. Pepsin
- B. Sucrase
- C. Pancreatic lipase
- D. Chymotrypsin
Explanation: Chemotrypsin is the enszyme that works at pH of 7. Indicating that it works at neutral condition
Correct answer: Chymotrypsin- A. Pepsin
- B. Trypsin
- C. Chymotrypsin
- D. Lactase
Explanation: Option D lactase is the enzyme, which is different from all other enzymes mentioned above
Correct answer: Lactase- A. Homologous to substrate
- B. Analogous to substrate
- C. Smaller than substrate
- D. Larger than substrate
Explanation: Homologous to substrate: Correct, as competitive inhibitors are structurally similar (homologous) to the substrate, meaning they share a…
Correct answer: Homologous to substrate- A. Few Nucleotides
- B. Few Nucleosides
- C. Few Saccharides
- D. Few Amino Acids
Explanation: Enzymes are completely made up of protein, so the active site is also made up of proteins
Correct answer: Few Amino Acids359. NAD is important?
- A. Enzyme
- B. Coenzyme
- C. Hormone
- D. Vitamin
Explanation: NAD is a very important co enzyme for different reactions happening in human body
Correct answer: Coenzyme- A. Penetration of the sperm into the Ovum
- B. Entrance of the sperm into the vagina tube
- C. Entrance of the sperm into the fallopian
- D. Inactivation of sperms after their failure to fertilize ovum
Explanation: The process of fusion of a sperm with the ovum is called fertilization.
Correct answer: Penetration of the sperm into the Ovum