Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Carbohydrates are more efficient storage form of the energy as compared to the triacylglycerols.
Reason (R) : Carbohydrates are more oxidized and hence yield more energy on oxidation.
In light of the above statements, choose the correct answer from the options given below:

• 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. Both (A) and (R) are false.

Hint:

Remember: \(\text{Lipids (fats)} \approx 9 \text{ kcal/g}\) vs. \(\text{Carbohydrates} \approx 4 \text{ kcal/g}\).
Fats are highly reduced, which is why they store more energy per unit mass.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The energy storage capacity of biological macromolecules depends on their oxidation state and how they are stored in tissues.

Step 2: Detailed Explanation:
Triacylglycerols (fats) are highly reduced molecules with a larger proportion of carbon-hydrogen bonds than carbohydrates.
Because fats are highly reduced and hydrophobic (meaning they are stored in anhydrous droplets), they yield roughly \(9 \text{ kcal/g}\) of energy upon complete metabolic oxidation.
In contrast, carbohydrates are more oxidized because they contain many polar hydroxyl groups.
This means they are heavily hydrated in storage and yield only around \(4 \text{ kcal/g}\) of energy.
As a result, triacylglycerols are a far more efficient energy storage medium than carbohydrates.
This makes Assertion (A) false.
Reason (R) is also false because the highly oxidized state of carbohydrates means they yield *less* energy upon oxidation compared to the more reduced lipids.
Both statements are incorrect.

Step 3: Final Answer:
Thus, the correct option is (D).