Question 1: Define aerobic respiration and explain its significance in cellular energy production.

Answer: Aerobic respiration is a process by which cells break down glucose in the presence of oxygen to produce energy, primarily in the form of ATP. It is significant because it provides a large amount of energy necessary for various cellular functions.

Question 1: List the main stages of aerobic respiration in order.

Answer: Glycolysis, the Krebs cycle (Citric Acid Cycle), and Electron Transport Chain.

Question 2: What role does oxygen play in aerobic respiration?

Answer: Oxygen acts as the final electron acceptor in the Electron Transport Chain, allowing the process to continue and enabling the production of a large amount of ATP.

Question 1: If one molecule of glucose produces approximately 36 molecules of ATP during aerobic respiration, calculate the total energy produced in kilojoules (kJ) given that each ATP molecule releases about 30.5 kJ upon hydrolysis. Show your working.

Answer: Total energy = 36 ATP × 30.5 kJ = 1098 kJ.

Question 1: Describe a basic experiment to measure the rate of aerobic respiration in yeast. Include the main variable you would change and a safety precaution.

Answer: An experiment could involve measuring the amount of carbon dioxide produced by yeast cultures at different temperatures. The main variable is temperature. Safety precautions include handling yeast and equipment with clean techniques to prevent contamination and ensuring proper disposal of biological materials.

Question 1: In an experiment, the amount of ATP produced from glucose was measured in two different conditions: with oxygen (aerobic) and without oxygen (anaerobic). The data shows that aerobic conditions yielded 36 ATP molecules per glucose, while anaerobic conditions yielded only 2 ATP molecules per glucose. Explain why there is such a difference in ATP yield.

Answer: Aerobic respiration is more efficient because it fully breaks down glucose using oxygen in the Electron Transport Chain, producing more ATP. In anaerobic conditions, the process is incomplete, and only glycolysis occurs, producing only 2 ATP per glucose molecule.

Question 1: Describe the role of the Electron Transport Chain in aerobic respiration and explain how it contributes to ATP production. (6 marks)

Answer: The Electron Transport Chain is a series of protein complexes located in the inner mitochondrial membrane. It receives electrons from NADH and FADH2, passing them through a series of carriers. As electrons move through the chain, energy is released and used to pump protons across the membrane, creating a gradient. This proton motive force drives ATP synthase to produce ATP. The chain is essential for the high yield of ATP in aerobic respiration.

Question 1: Explain how knowledge of aerobic respiration is used in the food industry, particularly in baking and brewing.

Answer: In baking and brewing, yeast uses aerobic respiration to produce carbon dioxide and alcohol. Controlling oxygen levels allows producers to optimize fermentation processes, ensuring proper rising of dough and desired alcohol content.