Final answer:
Carbohydrates primarily function as an energy source by being broken down into glucose, which provides energy as ATP. They are essential for proper cellular function, energy storage, structural support, and are a major source of daily calorie intake.
Step-by-step explanation:
The question asks which one of the following is a function of carbohydrates (as a class). The correct answer is that carbohydrates primarily function as an energy source. Carbohydrates are broken down into glucose, which provides energy in the form of adenosine triphosphate (ATP) through metabolic pathways. ATP is critical for proper cellular function, contributing to a myriad of biological processes including muscle contraction, nerve impulse propagation, and chemical synthesis.
Organisms use carbohydrates for various functions; they can store energy, provide structural support, and also play vital roles in functions of the immune system, in cell-cell recognition, among others. Complex carbohydrates like starch and glycogen or simple sugars like glucose and fructose are sources of fuel, and glucose, in particular, is used for ATP production in cells. Additionally, excess glucose in the body is stored as glycogen or converted into fat for later use.
Despite negative connotations associated with excessive consumption leading to weight gain, carbohydrates are essential in the diet and the primary macromolecules for energy supply to the body, providing about 70% of daily calorie requirements. They are naturally found in grains, fruits, and vegetables, and are also components of cell membranes and receptors.