What are the building blocks of carbohydrates?

Carbohydrates are organic compounds composed primarily of carbon, hydrogen, and oxygen, and they serve as a key source of energy for living organisms. The fundamental units that make up carbohydrates are monosaccharides. These simple sugars, such as glucose, fructose, and galactose, can join together in various ways to form larger carbohydrate molecules like disaccharides (e.g., sucrose) and polysaccharides (e.g., starch and cellulose).

Monosaccharides are not only the building blocks of more complex carbohydrates, but they also play vital roles in cellular metabolism. When organisms need energy, they can readily break down these simple sugars to release energy. Hence, understanding that monosaccharides are the basic units from which more complex carbohydrates are synthesized is essential for grasping how carbohydrates function in biological systems.

The other options represent different types of biological macromolecules. Amino acids are the building blocks of proteins, nucleotides are the building blocks of nucleic acids like DNA and RNA, and fatty acids are components of lipids. Each of these plays a critical role in biology, but they do not contribute to the structure of carbohydrates.