Which of the following best describes an enzyme?

• A. A protein that acts as a biological catalyst to speed up chemical reactions
• B. A carbohydrate that provides structural support in plants
• C. A nucleic acid that carries genetic information
• D. A type of lipid that stores energy in cells

Answer: (A)

Verified step by step guidance

1. Understand the definition of an enzyme: An enzyme is a biological molecule that speeds up chemical reactions by lowering the activation energy required for the reaction to occur. Enzymes are typically proteins.
2. Eliminate incorrect options: Review the other choices provided in the question. For example, carbohydrates provide structural support in plants (e.g., cellulose), nucleic acids carry genetic information (e.g., DNA and RNA), and lipids store energy in cells (e.g., triglycerides). None of these functions describe an enzyme.
3. Focus on the correct option: Identify the option that matches the definition of an enzyme. The correct description is 'A protein that acts as a biological catalyst to speed up chemical reactions.'
4. Recall examples of enzymes: To reinforce understanding, consider examples such as amylase (breaks down starch), catalase (breaks down hydrogen peroxide), and DNA polymerase (synthesizes DNA). These are all proteins that act as catalysts.
5. Conclude with the importance of enzymes: Highlight that enzymes are essential for life processes, as they enable reactions to occur efficiently under physiological conditions, such as normal body temperature and pH.