Enzymes: types, properties, action, classification
- The protein portion of an enzyme is called : Answer: 3. Apoenzyme Key idea: A conjugated enzyme has a protein part and a non-protein part. The protein part is the apoenzyme. The non-pro... 1
- Name the class of enzyme that usually catalyze the following reaction :S – G + S# → S + S# – GWhere, G → a group other than hydrogenS → a substrateS# → another substrate Answer: 3. Transferase Key idea: Transferases move a group (not hydrogen) from one substrate to another. The reaction S-G + S# → S + S#-G tr... 1
- Which one of the following enzymes contains 'Haem' as the prosthetic group? Answer: 4. Catalase Key idea: Catalase contains a haem group as its prosthetic group. RuBisCO has none, carbonic anhydrase uses zinc, and su... 1
- Regarding catalytic cycle of an enzyme action, select the correct sequential steps :A. Substrate enzyme complex formation.B. Free enzyme ready to bind with another substrate.C. Release of products.D. Chemical bonds of the substrate broken.E. Substrat… Answer: 2. E, A, D, C, B Key idea: catalytic cycle of an enzyme. Substrate binds to the active site (E) → enzyme-substrate complex forms (A)... 1
- Match List I with List II :List I:A. LipaseB. NucleaseC. ProteaseD. AmylaseList II:I. Peptide bondII. Ester bondIII. Glycosidic bondIV. Phosphodiester bondChoose the correct answer from the options given below : Answer: 4. A-II, B-IV, C-I, D-III Key idea: each enzyme breaks a particular bond. Lipase - ester bond in fats (II). Nuclease - phosphodieste... 1
- Inhibition of Succinic dehydrogenase enzyme by malonate is a classical example of: Answer: 4. Competitive inhibition Key idea: malonate looks like succinate, so it competes for the active site. Malonate is a structural anal... 1
- The cofactor of the enzyme carboxypeptidase is: Answer: 2. Zinc Key idea: carboxypeptidase is a metalloenzyme whose cofactor is a metal ion, zinc. Zinc ( Zn²⁺ ) is held in the active site... 1
- Melonate inhibits the growth of pathogenic bacteria by inhibiting the activity of Answer: 2. Succinic dehydrogenase Key idea: Malonate (written "melonate" in the question) is a competitive inhibitor of succinic dehydrogena... 1
- Given below are two statements:Statement I: Low temperature preserves the enzyme in a temporarily inactive state whereas high temperature destroys enzymatic activity because proteins are denatured by heat.Statement II: When the inhibitor closely rese… Answer: 2. Both Statement I and Statement II are true. Key idea: Both statements are standard facts about enzymes. Statement I is true: low... 1
- Match the following :(a) Inhibitor of catalytic activity (i) Ricin(b) Possess peptide bonds (ii) Malonate(c) Cell wall material in fungi (iii) Chitin(d) Secondary metabolite (iv) CollagenChoose the correct option from the following : Answer: 1. (a) (ii), (b) (iv), (c) (iii), (d) (i) Key idea: Match each item with its category. Inhibitor of catalytic activity: malonate (co... 1
- Consider the following statements :(A) Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group.(B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme.Select the correct option. Answer: 2. (A) is true but (B) is false. Statement A is true. A cofactor (organic or metal ion) that is tightly bound to the enzyme protein... 1
- Which one of the following statements is correct, with reference to enzymes ? Answer: 1. Holoenzyme = Apoenzyme + Coenzyme Key idea: An active conjugated enzyme has a protein part and a non-protein part. The protein pa... 1
- Which of the following describes the given graph correctly? Answer: 1. Exothermic reaction with energy A in presence of enzyme and B in absence of enzyme The graph shows energy released, and the arrow... 1
- A non-proteinaceous enzyme is Answer: 1. ribozyme Almost all enzymes are proteins, but a few RNA molecules also act as catalysts. Ribozyme is a catalytic RNA (for example... 1