Question

Assertion :Enzymes lower the activation energy of the reactant molecule to make its transition into product easier. Reason: Enzymes are highly substrate specific.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Both Assertion and Reason are incorrect.

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.

Transition state is the state of activated complex which is highly unstable and readily changes into the product. Enzymes are proteins which accelerates the rate of the reaction. The substrate and product have different energy state. The energy gap between the substrate and the product is known as activation energy which is the minimum energy required to initiate a reaction. The enzymes lowers the activation energy and leads to formation of activated complex, which is also known as transition state and finally changes to product.

Part of enzyme where substrate molecules gets attached is known as active site. On attachment to the active site the substrate is changed into product. The active site has a residue which helps in the attachment of substrate. The substrate molecules forms a temporary bond with the enzyme at the active site. The size and shape of the substrate determines its attachment to the active site. Lock and key model states that the specific substrate attaches to active site like a key fits in a specific lock.

So, the correct answer is option B.