Which term refers to the sum of the chemical reactions that occur within a cell to provide energy and synthesize new material?

• A. Metabolism
• B. Law
• C. Endosymbiotic theory
• D. Isotonic

Answer: (A)

Metabolism is the set of all chemical reactions that occur in a cell to provide energy and build new materials. It includes catabolic reactions that break down molecules to release energy and anabolic reactions that use that energy to synthesize larger, essential molecules. In the cell, metabolism fuels activities and supports growth and maintenance. The other terms don’t describe the overall network of biochemical reactions: a law is about rules, endosymbiotic theory explains how organelles like mitochondria may have originated, and isotonic refers to a solution’s effect on water movement, not energy production or biosynthesis.