Which statement best describes catabolic processes?

• A. They consume energy to build molecules
• B. They break down molecules to release energy
• C. They are always endergonic
• D. They do not produce any byproducts

Answer: (B)

Catabolic processes are best described as those that break down larger, complex molecules into smaller, simpler ones, which often results in the release of energy. This breakdown is crucial for providing the energy needed for various cellular activities. During catabolism, the chemical bonds in the larger molecules are broken, releasing energy that is then used for physiological processes, such as muscle contraction, active transport, or biosynthesis of other molecules that the body requires.

The essence of catabolic reactions is that they are exergonic, meaning they release energy. This is distinct from anabolic processes, which consume energy to synthesize more complex molecules from simpler ones. Therefore, the correct characterization of catabolic processes emphasizes energy release through molecular breakdown.