Question 1: Define metabolism in the context of cellular processes.

Answer: Metabolism is the sum of all chemical reactions that occur within a living organism to maintain life, including breaking down nutrients for energy and building cellular components.

Question 2: Explain the difference between catabolism and anabolism.

Answer: Catabolism involves breaking down complex molecules into simpler ones to release energy, while anabolism uses energy to build complex molecules from simpler ones.

Question 3: Describe the main stages of cellular respiration.

Answer: Cellular respiration consists of glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain, which together convert glucose into ATP energy.

Question 4: Calculate the amount of ATP produced from 1 molecule of glucose during aerobic respiration, given that glycolysis produces 2 ATP, the Krebs cycle produces 2 ATP, and the electron transport chain produces approximately 34 ATP.

Answer: 38 ATP

Question 5: Identify which stage of respiration occurs in the mitochondria.

Answer: Both B and C

Question 6: Fill in the blank: The process of glycolysis breaks down glucose into two molecules of __________.

Answer: pyruvate

Question 7: Explain why oxygen is essential for efficient ATP production during respiration.

Answer: Oxygen acts as the final electron acceptor in the electron transport chain, allowing the chain to continue functioning. Without oxygen, the chain halts, and ATP production via aerobic respiration decreases significantly, leading to less energy for the cell.

Question 8: Describe a practical experiment to measure the rate of respiration in yeast. Include variables to control and safety precautions.

Answer: An experiment can involve placing yeast in a sealed container with a glucose solution and measuring the production of carbon dioxide over time using a gas syringe or limewater. Variables to control include temperature, pH, and yeast concentration. Safety precautions include handling yeast and chemicals carefully, wearing gloves and goggles, and working in a well-ventilated area.

Question 9: Interpreting data: A sample of cells produces 5 mL of carbon dioxide in 10 minutes. If the initial volume of the container is 100 mL, what does this suggest about the cell’s metabolic activity?

Answer: It indicates that the cells are actively respiring, producing a measurable amount of carbon dioxide as a byproduct of metabolism.

Question 10: Apply your understanding of metabolism to explain how athletes improve their endurance using oxygen therapy or training.

Answer: Athletes enhance their endurance by increasing their lung capacity and efficiency of oxygen delivery to muscles, which improves aerobic respiration. Better oxygen supply allows more ATP to be produced during activity, delaying fatigue and enabling sustained physical effort.

Question 11: Which of the following statements best describes the relationship between metabolism and energy? A) Metabolism only involves energy storage. B) Metabolism includes both energy release and energy storage processes. C) Metabolism is only about breaking down molecules. D) Metabolism does not involve energy changes.

Answer: B