Question 1: Explain in your own words what anaerobic respiration is and why some organisms use this process instead of aerobic respiration.

Answer: Anaerobic respiration is a form of respiration that does not require oxygen. Some organisms use it to produce energy when oxygen is scarce or unavailable, allowing them to survive in anaerobic environments.

Question 2: Which of the following is a common product of anaerobic respiration in muscle cells?

Answer: Lactic acid

Question 3: Fill in the blank: During anaerobic respiration in muscle cells, glucose is broken down into __________ and lactic acid.

Answer: pyruvate

Question 4: Describe the main difference between aerobic and anaerobic respiration in terms of energy yield and oxygen requirement.

Answer: Aerobic respiration requires oxygen and produces a high yield of energy (about 36-38 ATP molecules per glucose). In contrast, anaerobic respiration does not require oxygen and produces a much lower energy yield (about 2 ATP molecules per glucose).

Question 1: Write the simplified chemical equation for anaerobic respiration in muscle cells.

Answer: Glucose → Lactic acid + Energy (ATP)

Question 2: Identify two substances that are produced during anaerobic respiration in yeast.

Answer: Ethanol and carbon dioxide

Question 1: Describe how anaerobic respiration is utilised in industry, giving a specific example.

Answer: Anaerobic respiration is used in brewing and baking; yeast ferments sugars to produce ethanol and carbon dioxide, which causes bread to rise and alcohol in beverages.

Question 2: State one disadvantage of relying on anaerobic respiration for energy production in human muscles during exercise.

Answer: It produces lactic acid, which can cause muscle fatigue and soreness.

Question 3: Explain why anaerobic respiration is less efficient than aerobic respiration.

Answer: Anaerobic respiration produces only 2 ATP molecules per glucose molecule because it bypasses the electron transport chain, which is necessary for the efficient production of energy in aerobic respiration.

Question 1: Identify one variable that could be changed in an experiment to investigate the rate of anaerobic respiration in yeast.

Answer: Temperature, sugar concentration, or yeast amount

Question 2: List one safety precaution that should be taken when conducting experiments involving yeast fermentation.

Answer: Ensure proper ventilation and handle ethanol vapours with care.