Question 67 of 782

when protein are broken down they provide

  • A. oxygen
  • B. carbonhydrate
  • C. energy
  • D. amino-acid

Correct Answer: D

Explanation
The correct option is D. amino-acid. Detailed Explanation:
  1. Understanding Protein Breakdown:
  2. Proteins are large, complex molecules made up of smaller units called amino acids. When proteins are consumed in the diet, they undergo a process called digestion in the body.
  3. During digestion, proteins are broken down into their constituent amino acids through the action of enzymes. This process occurs primarily in the stomach and small intestine.
  4. Role of Amino Acids:
  5. Once proteins are broken down into amino acids, these amino acids can be used by the body for various functions:
    • Building Blocks: Amino acids are essential for the synthesis of new proteins that the body needs for growth, repair, and maintenance of tissues.
    • Precursor Molecules: Some amino acids can be converted into other important molecules, such as neurotransmitters and hormones.
    • Energy Source: Although amino acids can be used for energy, this is not their primary role. The body prefers to use carbohydrates and fats for energy. However, in situations where carbohydrates are scarce (like prolonged fasting), amino acids can be converted into glucose through a process called gluconeogenesis.
  6. Why Other Options Are Incorrect:
  7. A. Oxygen:
    • Oxygen is not produced or released when proteins are broken down. Instead, oxygen is used in cellular respiration to help convert nutrients into energy. Therefore, this option is incorrect.
  8. B. Carbohydrate:
    • Carbohydrates are a separate class of macromolecules that are not produced from protein breakdown. While amino acids can be converted into glucose (a carbohydrate) under certain conditions, this is not a direct result of protein breakdown. Thus, this option is misleading.
  9. C. Energy:
    • While amino acids can be used to produce energy, the question specifically asks what proteins provide when they are broken down. The primary product of protein breakdown is amino acids, not energy directly. Energy is a secondary product that can be derived from amino acids if needed, making this option less accurate.
Summary of Key Points:
  • Proteins are broken down into amino acids during digestion.
  • Amino acids serve as building blocks for new proteins and can be converted into other important molecules.
  • Oxygen is not produced in protein breakdown, and carbohydrates are not a direct product of this process.
  • Energy can be derived from amino acids, but it is not the primary outcome of protein breakdown.
Revision Summary:
  • Proteins are digested into amino acids.
  • Amino acids are essential for protein synthesis and other bodily functions.
  • Oxygen and carbohydrates are not products of protein breakdown.
  • Energy can be derived from amino acids, but it is not the main focus of protein digestion.
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