Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: The major source of energy for the basic functioning of the cell is derived from oxidative metabolism.
Reason R: Mitochondria oxidize substrates to $CO_{2}$, transferring the high energy electron from molecular oxygen to glucose.

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is not the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Hint:

Energy comes FROM food (glucose) TO oxygen. Oxygen is the "drain," not the "source" of electrons.

Answer 1

The Correct Option is C

Step 1: Concept
Oxidative metabolism (cellular respiration) is the primary process for generating ATP in aerobic organisms.

Step 2: Meaning
ATP is produced by breaking down fuels (like glucose) and transferring electrons through an electron transport chain.

Step 3: Analysis
Assertion A is correct: most cellular energy comes from oxidative phosphorylation in the mitochondria. However, Reason R is scientifically incorrect. In cellular respiration, electrons are transferred from glucose (and other substrates) to oxygen, not the other way around. Oxygen acts as the final electron acceptor.

Step 4: Conclusion
Since the direction of electron transfer described in R is reversed, the statement is false. Final Answer: (C)