What term describes a molecule that catalyzes chemical reactions?

What term describes a molecule that catalyzes chemical reactions?

• A. Hormone
• B. Genetic code
• C. Hemoglobin
• D. Enzyme

Answer: (D)

Enzymes are the molecules that catalyze chemical reactions in living systems. They speed up reactions by lowering the activation energy, the energy barrier that must be overcome for reactants to become products, so processes occur quickly enough to sustain life. Enzymes are typically highly specific for their substrates, binding at an active site to form an enzyme–substrate complex and catalyzing a particular transformation. This specificity explains why only certain reactions are accelerated by a given enzyme. Hormones regulate physiology as signaling molecules, not catalysts. The genetic code stores information used to build proteins and RNAs, not to speed up reactions. Hemoglobin carries oxygen and carbon dioxide in the blood, functioning as a transport protein rather than a catalyst. While enzymes are usually proteins, some RNA molecules can also act as catalysts, but in most contexts the term enzyme refers to protein catalysts that drive metabolic reactions.

Enzymes are the molecules that catalyze chemical reactions in living systems. They speed up reactions by lowering the activation energy, the energy barrier that must be overcome for reactants to become products, so processes occur quickly enough to sustain life. Enzymes are typically highly specific for their substrates, binding at an active site to form an enzyme–substrate complex and catalyzing a particular transformation. This specificity explains why only certain reactions are accelerated by a given enzyme. Hormones regulate physiology as signaling molecules, not catalysts. The genetic code stores information used to build proteins and RNAs, not to speed up reactions. Hemoglobin carries oxygen and carbon dioxide in the blood, functioning as a transport protein rather than a catalyst. While enzymes are usually proteins, some RNA molecules can also act as catalysts, but in most contexts the term enzyme refers to protein catalysts that drive metabolic reactions.