The best answer to the question: Which statements describe the structure of each type of macromolecule, would be: A, B and D. C would be the only option here whose structure, as proposed in the statement, does not meet the chemical composition criteria of an amino acid, which is the building block of proteins.


Macromolecules are basically the building blocks of human life. Of these our bodies depend entirely to carry out their different functions, and without them, there would not be life. These macromolecules are known as such because they are built from much smaller, and more basic chemical units. Essentially, there are 4 major types of macromolecules: carbohydrates, lipids, proteins, and nucleic acids (DNA and RNA). All of them have one thing in common, and that is the presence of carbon as their building block. The variable elements would be hydrogen, oxygen, nitrogen and in some cases, phosphorus. From the options in the question, and given the request of the statement, three of the proposed statements effectively describe the chemical structures of the building blocks for carbs, lipids and nucleic acids, but that is not so for the building blocks of proteins, amino acids. Amino acids are not just built from carbon and nitrogen only; they will also count with hydrogen in their structure.