Question

The lock and key principle is related to

• A. Dark reaction
• B. Enzyme action
• C. Chemical action
• D. Hormonal action

Answer 1

Answer: (B)

Enzyme action

The lock and key hypothesis helps in explaining the mode of action of enzymes. According to this hypothesis, the catalytic property of enzymes is located at specific regions on their surface. These regions are called active sites. Similarly the substrates have on their surface specific areas called reactive sites. The active and reactive sites fit like a lock and key. The enzyme molecule holds the substrate molecules close together in such a way that their reactive sites are juxtaposed, thereby lowering the activation energy and facilitating their union to form a single large molecule. The enzyme molecule bring the reactant molecules into proper contact far faster than chance collisions at that temperature. The reactions are thus accelerated.

Thus, the correct answer is option B.