The term for a biological catalyst that speeds up chemical reactions is an enzyme. Enzymes are typically proteins that lower the activation energy required for reactions, facilitating various biochemical processes within living organisms. They are highly specific, acting on particular substrates and often requiring cofactors or coenzymes for optimal activity. Enzymes play vital roles in digestion, metabolism, and cellular functions. The study of enzymes is integral to fields such as biochemistry and molecular biology, helping to understand metabolic pathways and regulation of physiological processes.