Enzymes - classification, mechanism and cofactors — NEET & JEE Questions

Question 1 · difficulty L1 · recall

Enzymes accelerate biochemical reactions mainly by

• A. lowering activation energy
• B. increasing the equilibrium constant
• C. being permanently consumed
• D. raising product free energy

Question 2 · difficulty L2 · understanding

The protein portion of an enzyme is called:

• A. Apoenzyme
• B. Prosthetic group
• C. Cofactor
• D. Coenzyme

Question 3 · difficulty L2 · understanding

Which one of the following statements refers to Reductionist Biology?

• A. Chemical approach to study and understand living organisms
• B. Behavioural approach to study and understand living organisms
• C. Physico-chemical approach to study and understand living organisms
• D. Physiological approach to study and understand living organisms

Question 4 · difficulty L2 · understanding

Which one of the following enzymes contains 'Haem' as the prosthetic group?

• A. Succinate dehydrogenase
• B. Catalase
• C. RuBisCo
• D. Carbonic anhydrase

Question 5 · difficulty L2 · understanding

Name the class of enzyme that usually catalyze the following reaction : $$S-G+S^{\#} \rightarrow S+S^{\#}-G$$ Where, G $\rightarrow$ a group other than hydrogen $$S \rightarrow \text { a substrate }$$ $$S^{\#} \rightarrow \text { another substrate }$$

• A. Transferase
• B. Ligase
• C. Hydrolase
• D. Lyase

Question 6 · difficulty L3 · understanding

The following reaction depicts the activity of a particular class of enzymes : Identify the enzymes class ' $E$ ' from the following options :

• A. Transferases
• B. Isomerases
• C. Lyases
• D. Ligases

Question 7 · difficulty L3 · understanding

Ligases is a class of enzymes responsible for catalysing the linking together of two compounds. Which of the following bonds is not catalysed by it?

• A. C – C
• B. P – O
• C. C – O
• D. C – N

Question 8 · difficulty L3 · understanding

Enzymes that catalyse the removal of groups from substrates by mechanisms other than hydrolysis leaving double bonds, are known as :

• A. Transferases
• B. Oxidoreductases
• C. Dehydrogenases
• D. Lyases

Question 9 · difficulty L3 · understanding

The cofactor of the enzyme carboxypeptidase is:

• A. Zinc
• B. Niacin
• C. Flavin
• D. Haem

Question 10 · difficulty L3 · understanding

Inhibition of Succinic dehydrogenase enzyme by malonate is a classical example of:

• A. Cofactor inhibition
• B. Feedback inhibition
• C. Competitive inhibition
• D. Enzyme activation