Metabolism includes which of the following in addition to anabolism and catabolism?

• A. Both anabolism and catabolism
• B. Anabolism only
• C. Catabolism only
• D. None

Answer: (A)

Metabolism is the overall set of chemical reactions that sustain life, and it rests on two complementary types of processes: anabolic, which builds larger, more complex molecules using energy, and catabolic, which breaks down molecules into smaller pieces and releases energy. Together, these two sides cover the entire scope of metabolic activity. For example, protein synthesis is anabolic, consuming energy to assemble amino acids into proteins, while cellular respiration is catabolic, breaking down glucose to release energy. Because metabolism encompasses both building and breaking down, the option that includes both anabolic and catabolic processes is the best choice.