Question 1

What is an enzyme active site?

Accepted Answer

An active site is a specific three-dimensional region of an enzyme where a compatible substrate binds. It may be formed by amino acid residues that are far apart in the primary sequence but are brought together by tertiary folding.

Question 2

How do enzymes accelerate reactions?

Accepted Answer

Enzymes are biological catalysts that lower the activation energy of a reaction. They allow the reaction to proceed faster without being consumed, but they do not make an energetically impossible reaction possible.

Question 3

What does enzyme specificity mean?

Accepted Answer

Enzyme specificity means that an active site is compatible with particular substrates or classes of substrates. NCERT commonly explains this through the lock-and-key model, in which the substrate and active site have complementary features.

Question 4

How does temperature affect enzyme activity?

Accepted Answer

Enzyme activity generally rises with temperature up to an enzyme-specific optimum. Above the optimum, denaturation disturbs the protein's active-site geometry and activity falls; 37 degrees C is useful for many human enzymes but is not a universal optimum.

Question 5

Why does every enzyme have an optimum pH?

Accepted Answer

pH controls the ionisation of amino acid residues in an active site. If the charges required for substrate binding are disturbed, activity decreases, so each enzyme has its own optimum pH; examples include pepsin at about 2 and trypsin at about 8.

Enzyme Active Site Lab — Docking, Specificity & Factors

About this lab

Practice