Anaerobic respiration results in the production of

Step 1: Analyze the question The question asks how the energy yield of anaerobic respiration compares with that of aerobic respiration.

Step 2: Explain the concept

• Aerobic respiration (with oxygen) breaks glucose down completely: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + about 38 ATP (about 2870 kJ)
• Anaerobic respiration (without oxygen) breaks glucose down only partially: • In yeast (alcoholic fermentation): C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + 2 ATP (about 210 kJ) • In animal muscle (lactic acid fermentation): C₆H₁₂O₆ → 2C₃H₆O₃ + 2 ATP

Anaerobic respiration does release some energy, but the glucose is not fully oxidised. Ethanol or lactic acid still holds a lot of unreleased chemical energy.

Step 3: Evaluate the options

• A. More energy than aerobic: wrong, because aerobic gives far more.
• B. No energy: wrong, because a small amount (2 ATP) is produced.
• C. Equal energy: wrong, because the yields differ greatly.
• D. Less energy than aerobic: correct.

Step 4: Answer Anaerobic respiration produces less energy than aerobic respiration, so the answer is D.

Exam tip: Remember "Aerobic = Abundant energy (about 38 ATP); Anaerobic = A little energy (2 ATP)." Also remember that incomplete breakdown of glucose means the energy yield is low.