Which description of a macronutrient is correct?

• A. Carbohydrates are composed of long carbon chains, making them insoluble in water.
• B. Fats are the only inorganic macronutrient.
• C. Proteins are broken down into individual amino acids before being absorbed by the body.
• D. Unlike fats and proteins, carbohydrates contain nitrogen, along with carbon, hydrogen, and oxygen.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the definition of macronutrients. Macronutrients are nutrients required in large amounts by the body for energy and essential functions. The three main macronutrients are carbohydrates, proteins, and fats.
2. Step 2: Analyze the first statement: 'Carbohydrates are composed of long carbon chains, making them insoluble in water.' Carbohydrates are actually composed of carbon, hydrogen, and oxygen in a specific ratio (C_nH_2nO_n). They are generally soluble in water due to their polar hydroxyl (-OH) groups, especially simple carbohydrates like glucose.
3. Step 3: Analyze the second statement: 'Fats are the only inorganic macronutrient.' Fats are organic compounds because they contain carbon atoms bonded to hydrogen and oxygen. Inorganic compounds do not contain carbon-hydrogen bonds, so this statement is incorrect.
4. Step 4: Analyze the third statement: 'Proteins are broken down into individual amino acids before being absorbed by the body.' Proteins are indeed broken down into amino acids by enzymes like pepsin and trypsin during digestion. These amino acids are then absorbed into the bloodstream through the small intestine.
5. Step 5: Analyze the fourth statement: 'Unlike fats and proteins, carbohydrates contain nitrogen, along with carbon, hydrogen, and oxygen.' This is incorrect because carbohydrates do not contain nitrogen. Proteins are the macronutrient that contains nitrogen, in addition to carbon, hydrogen, and oxygen, due to the presence of amino groups (-NH₂) in their structure.