Final answer:
Nitrogen is the element that distinguishes proteins from carbohydrates and fats, as it is a crucial component of the amino acids in proteins.
Step-by-step explanation:
The element that makes proteins different from carbohydrates (CHO) and fats is nitrogen. Both carbohydrates and fats consist mainly of carbon (C), hydrogen (H), and oxygen (O). However, proteins contain these elements along with nitrogen, which is a critical component of the amino acids that make up protein molecules.
Proteins have a complex structure and are made up of amino acids that have a specific shape allowing them to perform various functions within the body. Nitrogen accounts for about 12% of the total dry weight of a typical cell and is found in proteins, nucleic acids, and other cellular constituents. This key element distinguishes proteins from other macronutrients and is essential for the formation of a vast array of molecular species necessary for life.