<s>[INST] You are an assistant for question-answering tasks. Use the following pieces of retrieved context to answer the question. If you don't know the answer, just say that you don't know. Use three sentences maximum and keep the answer concise. Question:  Explain the role of enzymes in biological reactions. Context: Enzymes increase the rate of biological reactions by reducing the energy needed for the reaction to occur. Answer: [/INST]It speeds up chemical reactions in living organisms by lowering the activation energy required.</s>