Question

Among the following respiratory substrates, which one is the main source of energy?

• A. Organic acids
• B. Proteins
• C. Fats
• D. Carbohydrates

Hint:

Glucose is the universal fuel for respiration in almost all living organisms.

Answer 1

The Correct Option is D

Step 1: Understanding respiratory substrates.
Respiratory substrates are compounds that are oxidized during respiration to release energy required for cellular activities.
Step 2: Role of carbohydrates.
Carbohydrates, especially glucose, are the primary and most preferred source of energy in living organisms. They are easily oxidized during respiration.
Step 3: Comparison with other substrates.
Proteins are mainly used for growth and repair.
Fats are long-term energy reserves but are not the immediate source.
Organic acids contribute minimally to respiration.
Step 4: Conclusion.
Carbohydrates are the main respiratory substrate and the chief source of energy.