NEET Biology Enzymes MCQs Set 01

Practice MCQs for NEET Biology Enzymes

Explore reliable objective questions for Enzymes tailored for NEET learners. Utilizing these Biology multiple-choice formats ensures thorough preparation and strengthens problem-solving speed for upcoming school assessments.

Access Enzymes Questions and Solutions

View or download the dedicated Enzymes MCQ resource below. Practicing these 50 objective questions regularly builds familiarity with standard exam patterns and helps secure higher marks in final Biology evaluations.

Multiple Choice Questions

Question 1: Which of the following coenzyme is a derivative of pantothenic acid ? (vit - B complex) ?
(a) NAD
(b) NADP
(c) FAD
(d) Co-A
Show Answer & Explanation

Answer: (d) Co-A

Explanation:
1. Coenzyme A is derived from pantothenic acid (vitamin B₅).

Teacher's Note:
1. NAD comes from niacin and FAD from riboflavin.

Question 2: Sucrose is converted into glucose and fructose by enzyme :-
(a) Maltase
(b) Amylase
(c) Invertase
(d) Hexokinase
Show Answer & Explanation

Answer: (c) Invertase

Explanation:
1. Invertase (sucrase) hydrolyses sucrose into glucose and fructose.

Teacher's Note:
1. Maltase acts on maltose.

Question 3: Which of the following statements regarding enzyme inhibition is correct ?
(a) Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate
(b) Competitive inhibition is seen, when a substrate competes with an enzyme for binding to an inhibitor protein
(c) Competitive inhibition is seen, when the substrate and the inhibitor compete for the active site on the enzyme
(d) Non-competitive inhibitors often bind to the enzyme irreversibly.
Show Answer & Explanation

Answer: (c) Competitive inhibition is seen, when the substrate and the inhibitor compete for the active site on the enzyme

Explanation:
1. A competitive inhibitor and substrate compete for the same active site.

Teacher's Note:
1. Competitive inhibition is reversible.

Question 4: Inhibition of succinic dehydrogenase by malonate is an example of
(a) Competitive inhibition
(b) Non competitive inhibition
(c) Allosteric inhibition
(d) Enzyme repression
Show Answer & Explanation

Answer: (a) Competitive inhibition

Explanation:
1. Malonate resembles the substrate succinate and competes for the active site of succinic dehydrogenase.

Teacher's Note:
1. Competitive inhibition can be overcome by raising the substrate concentration.

Question 5: An organic substance bound to an enzyme and essential for its activity is called
(a) Apoenzyme
(b) Isoenzyme
(c) Coenzyme
(d) Holoenzyme
Show Answer & Explanation

Answer: (c) Coenzyme

Explanation:
1. A coenzyme is an organic non-protein substance that binds to the enzyme and is essential for its activity.

Teacher's Note:
1. The protein part is the apoenzyme.

Question 6: Low temperature preserves the enzyme in a ...'A'... state whereas high temperature destroys enzymatic activity because proteins are ...'B'... by heat. Choose the correct option:-
(a) A = temporarily inactive, B = denatured
(b) A = permanently inactive, B = temporarily inactive
(c) A = permanently inactive, B = denatured
(d) A = denatured, B = temporarily inactive
Show Answer & Explanation

Answer: (a) A = temporarily inactive, B = denatured

Explanation:
1. Low temperature only temporarily inactivates enzymes; high temperature denatures them permanently.

Teacher's Note:
1. Enzymes work again when warmed.

Question 7: The essential chemical components of many coenzymes are :
(a) Vitamins
(b) Proteins
(c) Nucleic acids
(d) Carbohydrates
Show Answer & Explanation

Answer: (a) Vitamins

Explanation:
1. Many coenzymes are derivatives of vitamins, for example NAD from niacin.

Teacher's Note:
1. Cofactors may be coenzymes, prosthetic groups or metal ions.

Question 8: An example of competitive inhibition of an enzyme is the inhibition of :
(a) Succinic dehydrogenase by malonic acid
(b) Cytochrome oxidase by cyanide
(c) Hexokinase by glucose - 6 phosphate
(d) Carbonic anhydrase by carbon - dioxide
Show Answer & Explanation

Answer: (a) Succinic dehydrogenase by malonic acid

Explanation:
1. Malonate resembles succinate and competes for the active site of succinic dehydrogenase.

Teacher's Note:
1. Competitive inhibitors are substrate analogues.
2. Cyanide acts on cytochrome oxidase non-competitively.

Question 9: For its activity, carboxypeptidase requires :-
(a) Niacin
(b) Copper
(c) Zinc
(d) Iron
Show Answer & Explanation

Answer: (c) Zinc

Explanation:
1. Carboxypeptidase is a zinc metalloenzyme and needs Zn²⁺ as cofactor.

Teacher's Note:
1. Metal ions are cofactors of many enzymes.

Question 10: How the presence of an enzyme affects the activation energy of a reaction ?
(a) It becomes increased
(b) It becomes decreased
(c) It is first increased and then decreased
(d) Activation energy in not affected at all
Show Answer & Explanation

Answer: (b) It becomes decreased

Explanation:
1. Enzymes lower the activation energy of a reaction.

Teacher's Note:
1. They do not change the equilibrium or the free energy change.

Question 11: Allosteric enzymes have allosteric sites for –
(a) Inhibition only
(b) Activation only
(c) Reduction in activation energy
(d) Both activation and inhibition
Show Answer & Explanation

Answer: (d) Both activation and inhibition

Explanation:
1. An allosteric enzyme has a regulatory site to which activators or inhibitors bind.

Teacher's Note:
1. Binding changes the shape of the active site.

Question 12: Substrate concentration at which an enzyme attains half of its max. velocity is ?
(a) Half life of enzyme
(b) Km-constant of enzyme
(c) Concentration ratio
(d) None
Show Answer & Explanation

Answer: (b) Km-constant of enzyme

Explanation:
1. The substrate concentration at half of the maximum velocity is the Michaelis constant Km.

Teacher's Note:
1. A low Km means high affinity for the substrate.

Question 13: The catalytic efficiency of two different enzyme can be compared by the :
(a) The Km value
(b) The pH optimum value
(c) Formation of the product
(d) Molecular size of the enzyme
Show Answer & Explanation

Answer: (a) The Km value

Explanation:
1. A lower Km means a higher affinity of the enzyme for its substrate and so greater efficiency.

Teacher's Note:
1. Km is the characteristic constant of an enzyme-substrate pair.

Question 14: Which one of the following statements in incorrect?
(a) In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme.
(b) The competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex.
(c) The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate.
(d) A competitive inhibitor reacts reversibly with the enzyme to form an enzyme- inhibitor complex.
Show Answer & Explanation

Answer: (c) The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate.

Explanation:
1. A competitive inhibitor raises the apparent Km of the enzyme; it does not decrease it.

Teacher's Note:
1. Vmax is unchanged.

Question 15: Enzymes, which catalyse the transfer of hydrogen (H) between two substrates, are called :-
(a) Transferases
(b) Oxidoreductases
(c) Isomerases
(d) Hydrolases
Show Answer & Explanation

Answer: (b) Oxidoreductases

Explanation:
1. Oxidoreductases catalyse transfer of hydrogen or electrons between substrates.

Teacher's Note:
1. Dehydrogenases belong to this class.

Question 16: Who coined the term enzyme ?
(a) Pasteur
(b) Buchner
(c) Kuhne
(d) Sumner
Show Answer & Explanation

Answer: (c) Kuhne

Explanation:
1. Kuhne coined the term enzyme.

Teacher's Note:
1. Sumner crystallised urease; Buchner discovered zymase.

Question 17: The first enzyme isolated in crystalline form was
(a) Catalase
(b) Urease
(c) Peroxidase
(d) Amylase
Show Answer & Explanation

Answer: (b) Urease

Explanation:
1. Sumner (1926) crystallised urease from jack bean.

Teacher's Note:
1. It proved that enzymes are proteins.

Question 18: Enzyme were discovered for the first time in
(a) Bacteria
(b) Yeast
(c) Algae
(d) Spinach
Show Answer & Explanation

Answer: (b) Yeast

Explanation:
1. Buchner obtained the first enzyme (zymase) from yeast.

Teacher's Note:
1. The word enzyme means in yeast (Greek).

Question 19: Which enzyme is chemically not a protein ?
(a) Hexokinase
(b) Synthetase
(c) Endonuclease
(d) Ribozyme
Show Answer & Explanation

Answer: (d) Ribozyme

Explanation:
1. Ribozymes are catalytic RNA molecules, so they are not proteins.

Teacher's Note:
1. All other options are protein enzymes.

Question 20: Three of the following statements about enzymes are correct and one is wrong. Which one is wrong?
(a) Enzymes are denatured at high temperatures but in certain exceptional organisms they are effective even at temperatures 80°-90°C
(b) Enzymes are highly specific
(c) Most enzymes are proteins but some are lipids
(d) Enzymes require optimum pH for maximal activity
Show Answer & Explanation

Answer: (c) Most enzymes are proteins but some are lipids

Explanation:
1. Enzymes are proteins (or RNA in ribozymes), never lipids.

Teacher's Note:
1. Thermophilic enzymes work even at 80°-90°C.

Question 21: Which one of the following statements is correct, with reference to enzymes ?
(a) Holoenzyme = Apoenzyme + Coenzyme
(b) Coenzyme = Apoenzyme + Holoenzyme
(c) Holoenzyme = Coenzyme + Co-factor
(d) Apoenzyme = Holoenzyme + Coenzyme
Show Answer & Explanation

Answer: (a) Holoenzyme = Apoenzyme + Coenzyme

Explanation:
1. Holoenzyme is the complete active enzyme: apoenzyme (protein) + cofactor.

Teacher's Note:
1. Cofactor can be coenzyme, prosthetic group or metal.

Question 22: In plants enzymes are present in
(a) Only in flowers
(b) Only in leaves
(c) All the living cells of plant body
(d) Only in parenchyma
Show Answer & Explanation

Answer: (c) All the living cells of plant body

Explanation:
1. Enzymes occur in all living cells of the plant.

Teacher's Note:
1. Enzymes control all reactions of life.

Question 23: Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these :
(a) enhance oxidative metabolism
(b) are conjugated proteins
(c) are exclusively synthesized in the body of a living organism
(d) help in regulating metabolism
Show Answer & Explanation

Answer: (d) help in regulating metabolism

Explanation:
1. All three regulate metabolism.

Teacher's Note:
1. Enzymes catalyse, hormones signal, vitamins act as coenzymes.

Free study material for Biology

Multiple Choice Questions (MCQs) for NEET Biology Enzymes

NEET Biology Enzymes Objective Test Questions

Explore reliable practice questions for Enzymes tailored for NEET Biology learners. Use these multiple-choice formats to evaluate preparedness and strengthen problem-solving skills.

NCERT-Aligned Objective Questions and Solutions

Built using the official NCERT book for NEET, these Biology objective sets provide reliable academic guidance. Pair your practice with our recommended NCERT solutions to master optimal problem-solving approaches.

Next Steps in Your Exam Preparation

Explore our broader library of printable assignments, chapter notes, and mock tests designed to support continuous revision and secure higher marks in NEET assessments.

FAQs

Where can I access latest NEET Biology Enzymes MCQs Set 01?

You can get most exhaustive NEET Biology Enzymes MCQs Set 01 for free on StudiesToday.com. These MCQs for NEET Biology are updated for the 2026-27 academic session as per NEET examination standards.

Are Assertion-Reasoning and Case-Study MCQs included in the Biology NEET material?

Yes, our NEET Biology Enzymes MCQs Set 01 include the latest type of questions, such as Assertion-Reasoning and Case-based MCQs. 50% of the NEET paper is now competency-based.

How do practicing Biology MCQs help in scoring full marks in NEET exams?

By solving our NEET Biology Enzymes MCQs Set 01, NEET students can improve their accuracy and speed which is important as objective questions provide a chance to secure 100% marks in the Biology.

Do you provide answers and explanations for NEET Biology Enzymes MCQs Set 01?

Yes, Biology MCQs for NEET have answer key and brief explanations to help students understand logic behind the correct option as its important for 2026 competency-focused NEET exams.

Can I practice these Biology NEET MCQs online?

Yes, you can also access online interactive tests for NEET Biology Enzymes MCQs Set 01 on StudiesToday.com as they provide instant answers and score to help you track your progress in Biology.