Carbohydrates are a diverse class of carbon-based molecules that are rich in hydroxyl groups (–OH). Commonly referred to as saccharides, which is derived from the Greek word for sugars, carbohydrates play essential roles in biological systems. The term "carbohydrates" was first introduced in the 1800s to describe compounds with the general formula C_nH_{2n}O_n, where n is greater than or equal to 3. This formula indicates that for each carbon atom, there is a corresponding water molecule, illustrating the hydrated nature of these compounds.
Simple carbohydrates, or monosaccharides, adhere closely to this formula. A well-known example is glucose, which has the chemical formula C_6H_{12}O_6. In glucose, there are 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms, fitting the aforementioned formula perfectly. This hydration of carbon atoms is a defining characteristic of simple carbohydrates.
In contrast, complex carbohydrates may deviate from this standard formula. They can include additional atoms such as phosphorus, nitrogen, or sulfur. For instance, a complex carbohydrate may have a chemical formula that includes a phosphorus atom, indicating its derivative nature from simpler carbohydrates. Even if the number of hydrogen and oxygen atoms varies, as long as the structure is derived from the basic carbohydrate framework, it is still classified as a carbohydrate.
Understanding the distinctions between simple and complex carbohydrates is crucial as we explore their various forms and functions in biological systems. This foundational knowledge will be built upon in subsequent lessons, where practical applications and deeper insights into carbohydrates will be discussed.
