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 31 of 32
- A. Enzymes start to denature
- B. Enzymes start to re-nature
- C. Enzymes work best
- D. Enzymes are reactivated
Explanation: Maximum temperature refers to a temperature at which enzymes start to breakdown and denature.
Correct answer: Enzymes start to denature- A. Saturation
- B. Inhibition
- C. Denaturation
- D. Composition
Explanation: Enzymes are protein in nature. At a temperature higher than optimum temperature, the 3D shape of active site denatures and substrate…
Correct answer: Denaturation- A. Enzyme start denaturing
- B. Enzyme becomes hyperactive
- C. Enzyme work at their best
- D. Inactive enzyme getting reactived
Explanation: Minimum temperature is the term used when an inactive enzyme starts getting reactive.
Correct answer: Inactive enzyme getting reactived- A. 30oC
- B. 40oC
- C. 50oC
- D. 20oC
Explanation: Enzymes generally have an optimal temperature at which they exhibit their highest activity.
Correct answer: 40oC- A. Enzymes start to denature
- B. Enzymes start to re-nature
- C. Enzymes work best
- D. Enzymes are reactivated
Explanation: The term "maximum temperature" means the point at which enzymes start to denature (Option A).
Correct answer: Enzymes start to denature- A. Maximum temperature
- B. Absolute temperature
- C. Critical temperature
- D. Optimum temperature
Explanation: Enzymes are biological catalyst, which are used to speed up the rate of chemical reactions taking place in body.
Correct answer: Optimum temperature- A. It increases the enzyme activity
- B. Stops the reaction
- C. Decreases the enzyme activity
- D. Both Options B and C are correct
Explanation: is temperature of a reaction medium increases above the optimum temperature then it stops reaction by decreasing enzyme activity because…
Correct answer: Both Options B and C are correct- A. Denaturation
- B. Composition
- C. Inhibition
- D. Saturation
Explanation: Saturation refers to the point in an enzymatic reaction where all of the enzyme's active sites are occupied by substrate molecules…
Correct answer: Saturation- A. The binding of the active site to the substrate causes the enzyme to change shape
- B. The substrate and active site have complementary shapes that form temporary bonds
- C. The substrate causes a change in enzymes shape so the active site can bind
- D. The substrate changes shape so it can bind to the active site
Explanation: a) The binding of the active site to the substrate causes the enzyme to change shape:This option describes the induced fit model…
Correct answer: The binding of the active site to the substrate causes the enzyme to change shape- A. Koshland
- B. Robin Williams
- C. Rudolph Virchow
- D. Emil Fischer
Explanation: The lock and key model was proposed by Emil Fischer who was a german scientist and receiver of the nobel prize in chemistry.
Correct answer: Emil Fischer- A. Reactants
- B. Enzymes
- C. Products
- D. All of these
Explanation: The substrate bind to the enzyme which acts as catalysts in the conversion of the substrate to the product.
Correct answer: Products- A. Change in pH of enzyme
- B. Formation of ES complex
- C. Change in the shape of substrate
- D. Change in temperature
Explanation: B is correct .Formation of Enzyme Substrate complex is the step causes activation of catalytic site of an enzyme.
Correct answer: Formation of ES complex- A. Key
- B. Active site
- C. Hyperactive site
- D. None of these options are correct
Explanation: The substrate binds to a specific region on the enzyme called the active site.
Correct answer: Active site- A. 32 F
- B. 313 K
- C. 46 C
- D. 37 C
Explanation: This optimal temperature is usually around human body temperature (37 oC) for the enzymes in human cells
Correct answer: 37 C- A. Phenylalanine hydroxylase
- B. Phenylalanine oxidase
- C. Phenylalanine phosphate
- D. None of these
Explanation: Explanation:Phenylalanine hydroxylase is an enzyme that converts the amino acid phenylalanine to tyrosine.
Correct answer: Phenylalanine hydroxylase- A. Not produced in complete form
- B. It does not work efficiently at that time
- C. Quite capable of destroying cells internal structure
- D. None of the above
Explanation: Explanation:Pepsin is a protein-digesting enzyme and is capable of destroying cells' internal structure, as a result, it is secreted in an…
Correct answer: Quite capable of destroying cells internal structure- A. Amylase
- B. Apoenzyme
- C. Holoenzyme
- D. Coenzyme
Explanation: Option A is incorrect because Amylase is the enzyme that breakdown carbohydrates.Option B is incorrect because Apoenzyme is the enzyme…
Correct answer: Holoenzyme618. If the cofactor is covalently or tightly and permanently bonded to enzyme then it will be called:
- A. Coenzyme
- B. Prosthetic group
- C. Activator
- D. Apoenzyme
Explanation: The detachable cofactor is known as an activator if it is an inorganic ion.
Correct answer: Prosthetic group619. Some enzymes require helper which is non-protein part for its efficient functioning that is called:
- A. Accelerator
- B. Cofactor
- C. Prosthetic group
- D. Apoenzyme
Explanation: Some enzymes require non protein parts for their proper functioning. If the non-protein part is covalently bonded, it is known as a…
Correct answer: Cofactor- A. Prosthetic group
- B. Activator
- C. Co-enzyme
- D. Inhibitor
Explanation: Mg2+ is an essential inorganic activator for enzyme phosphatase, not to be confused with the prosthetic group.
Correct answer: Activator