Catabolism together with anabolism is a part of metabolism. It is the set of metabolic pathways in which the molecules are broken down into smaller units and the energy is released. Released energy of catabolism (in a form of ATP) is used for the maintenance and growth of cells. Examples of catabolic processes are glycolysis, the citric acid cycle or degradation of macromolecules: proteins into amino acids, lipids into free fatty acids...
Ans: Most genes contain the information needed to make functional molecules called proteins. (A few genes produce regulatory molecules that help the cell assemble proteins.) The journey from gene to protein is complex and tightly controlled within each cell.