Question

Given below are two statements regarding anaerobic respiration in the muscles.
Statement (I): In muscles, NADH+H\({}^{+}\) produced during glycolysis is reoxidised to NAD.
Statement (II): One proton and two electrons produced, which are donated to pyruvic acid which yields lactic acid leading to muscle fatigue.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Lactic acid formation needs two protons and two electrons, not one proton.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
When oxygen is short in muscles, NADH formed in glycolysis must be oxidised back to NAD so that glycolysis can continue.

Step 2: Statement (I)
Lactate dehydrogenase uses pyruvic acid as the hydrogen acceptor and reoxidises NADH + H to NAD. So Statement (I) is correct.

Step 3: Statement (II)
Pyruvic acid becomes lactic acid by gaining two hydrogen atoms, which means two protons and two electrons, not one proton. So Statement (II) is incorrect as written.

Final Answer:
Statement (I) is correct but Statement (II) is incorrect. \[ \boxed{\text{(C) }\text{Statement (I) is correct but Statement (II) is incorrect.}} \]