OCR GCSE Biology 2026 – 400 Free Practice Questions to Pass the Exam

The word equation for anaerobic respiration in animals is accurately represented by the transformation of glucose into lactic acid and energy. In an anaerobic environment, animals, including humans, utilize glucose for energy production when oxygen is limited. Instead of undergoing aerobic respiration, which requires oxygen and produces carbon dioxide and water, anaerobic conditions lead to the conversion of glucose into lactic acid.

This process is particularly relevant during intense exercise when oxygen levels may not meet the demands of muscle cells for energy. The production of lactic acid can accumulate in muscles, leading to fatigue and a burning sensation. Eventually, once oxygen becomes available again, lactic acid can be converted back to glucose in a process that occurs primarily in the liver. This emphasizes the importance of anaerobic respiration in generating immediate energy during short bursts of activity when oxygen supply is compromised.