Question 1: Anaerobic respiration occurs in the absence of oxygen and allows cells to produce energy when oxygen is scarce. It results in the formation of different waste products depending on the organism.

Answer: Anaerobic respiration allows cells to produce energy without oxygen, producing waste products like lactic acid or ethanol.

Question 1: Define anaerobic respiration.

Answer: Anaerobic respiration is a form of respiration that does not require oxygen, producing energy and waste products like lactic acid or ethanol.

Question 2: Describe the main difference between aerobic and anaerobic respiration.

Answer: Aerobic respiration requires oxygen and produces more energy, while anaerobic respiration does not require oxygen and produces less energy.

Question 3: Name one organism that undergoes anaerobic respiration and the waste product it produces.

Answer: Muscle cells during intense exercise produce lactic acid.

Question 1: If a muscle cell produces 2 ATP molecules during anaerobic respiration per glucose molecule, how many ATP molecules are produced from 10 glucose molecules?

Answer: 20 ATP

Question 2: Using the formula: Energy produced (kJ) = Number of ATP molecules × 30.5 kJ (approximate energy per ATP), calculate the total energy released from 15 ATP molecules.

Answer: 457.5 kJ

Question 1: Describe a simple experiment to test whether muscle cells produce lactic acid during anaerobic respiration. Include variables to control and safety precautions.

Answer: An experiment could involve exercising muscle tissue in a controlled environment, measuring lactic acid levels using a test strip before and after exercise. Variables to control include temperature, pH, and duration of exercise. Safety precautions include handling tissues carefully, avoiding excessive strain, and disposing of biological materials properly.

Question 1: In an experiment, muscle samples were tested for lactic acid concentration after different durations of intense exercise. The results showed: 5 mmol/L after 1 minute, 12 mmol/L after 3 minutes, and 20 mmol/L after 5 minutes. Explain what these results suggest about anaerobic respiration during exercise.

Answer: The increasing lactic acid levels indicate that anaerobic respiration is occurring more rapidly during sustained intense exercise, producing more waste as oxygen becomes depleted.

Question 1: Explain why anaerobic respiration is less efficient than aerobic respiration and discuss its importance during short bursts of activity. (6 marks)

Answer: Anaerobic respiration produces less ATP per glucose molecule compared to aerobic respiration because it bypasses the complete oxidation of glucose, leading to the accumulation of waste products like lactic acid. Despite being less efficient, it is crucial during short bursts of activity when oxygen supply is limited, allowing muscles to continue functioning temporarily.

Question 1: Describe one industrial process that relies on anaerobic respiration and explain its significance.

Answer: Anaerobic fermentation is used in the production of alcohol and bioethanol, which are important for beverages and biofuel industries.

Question 2: Explain how athletes might benefit from understanding anaerobic respiration during training.

Answer: Athletes can tailor their training to improve their anaerobic capacity, enabling them to perform better during short, intense activities by increasing lactic acid tolerance and muscle efficiency.