Which of the following best describes a biological catalyst?

• A. A molecule that stores genetic information in cells.
• B. A substance, typically a protein, that speeds up chemical reactions in living organisms without being consumed in the process.
• C. A lipid that forms the main component of cell membranes.
• D. A carbohydrate that provides energy for cellular activities.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the term 'biological catalyst.' A biological catalyst is a substance that increases the rate of a chemical reaction in living organisms without being consumed or permanently altered in the process.
2. Step 2: Recognize that enzymes are the most common biological catalysts. Enzymes are typically proteins, although some RNA molecules (ribozymes) can also act as catalysts.
3. Step 3: Eliminate incorrect options by analyzing their definitions. For example, a molecule that stores genetic information refers to DNA or RNA, not a catalyst. Similarly, lipids and carbohydrates have distinct roles in cell membranes and energy storage, respectively, and are not catalysts.
4. Step 4: Focus on the correct description: A biological catalyst is a substance, typically a protein, that speeds up chemical reactions in living organisms without being consumed in the process.
5. Step 5: Conclude that the correct answer is the option describing a substance that speeds up chemical reactions in living organisms without being consumed in the process.