Which statement characterizes catabolism?

Which statement characterizes catabolism?

• A. It builds larger molecules using energy
• B. It breaks down complex molecules to release energy
• C. It stores energy by creating glycogen
• D. It requires oxygen in all cases

Answer: (B)

Catabolism is the energy-releasing side of metabolism. It involves breaking down larger, complex molecules into smaller ones and, in the process, liberates chemical energy that the cell captures as ATP (and other carriers like NADH). This energy then powers other cellular activities, such as muscle contraction during exercise. Examples include glycolysis breaking down glucose, fatty acid breakdown (beta-oxidation), and digestion of macromolecules into usable units. That’s why the statement describing catabolism as breaking down complex molecules to release energy is the best fit. In contrast, making larger molecules from smaller ones uses energy (anabolism), storing energy by creating glycogen is anabolic, and while some catabolic steps can involve oxygen later in respiration, not all catabolic processes require oxygen.

Catabolism is the energy-releasing side of metabolism. It involves breaking down larger, complex molecules into smaller ones and, in the process, liberates chemical energy that the cell captures as ATP (and other carriers like NADH). This energy then powers other cellular activities, such as muscle contraction during exercise. Examples include glycolysis breaking down glucose, fatty acid breakdown (beta-oxidation), and digestion of macromolecules into usable units. That’s why the statement describing catabolism as breaking down complex molecules to release energy is the best fit. In contrast, making larger molecules from smaller ones uses energy (anabolism), storing energy by creating glycogen is anabolic, and while some catabolic steps can involve oxygen later in respiration, not all catabolic processes require oxygen.