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1 BIOLOGY MCQS

The energy value of food is measured in _______?

  • Joule
  • Calories
  • Tesla
  • Proteins
Correct Answer: B. Calories

Detailed Explanation

The energy value of food is the amount of energy that the human body can obtain from nutrients after digestion and metabolism. This energy is essential for carrying out all bodily functions, including movement, growth, repair of tissues, and maintaining body temperature. The unit used to measure this energy is the calorie (Cal).


What Is a Calorie?




  • A calorie is a unit of energy that indicates the amount of heat required to raise the temperature of 1 kilogram of water by 1°C.




  • In nutrition, Calories (with a capital C) or kilocalories (kcal) are commonly used, where 1 kcal = 1000 small calories.




How Food Provides Energy:




  1. Carbohydrates: Main energy source, providing 4 kcal per gram.




  2. Proteins: Supply energy (4 kcal per gram) but are mainly used for tissue repair and growth.




  3. Fats: High-energy nutrients, providing 9 kcal per gram.




  4. Alcohol (optional): Provides about 7 kcal per gram but is not an essential nutrient.




When food is metabolized, chemical energy stored in its molecules is released and converted into ATP (adenosine triphosphate), which powers cellular activities.


Why Other Options Are Incorrect:




  • Joule: The SI unit of energy (1 kcal = 4184 Joules), but nutrition science predominantly uses Calories.




  • Tesla: A unit of magnetic field strength, unrelated to food energy.




  • Proteins: A nutrient that provides energy but is not a measurement unit.




Thus, the correct answer is Option B: Calories, as it is the standard unit used globally to express the energy value of food consumed by humans and animal.

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