Biochemistry Questions Biochemistry Questions / Discuss the significance of using alternative electron acceptors and donors in anaerobic respiration compared to aerobic respiration, focusing on the metabolic versatility of E. coli.

Alternative electron acceptors are necessary in prokaryotic metabolic flexibility. Being able to use different terminal electron acceptors allows E. coli to grow in a wide range of conditions (reducing, oxidising). In anaerobic respiration, oxygen is not present and so cannot be used as the terminal electron acceptor.

E. coli is a facultative anaerobe, able to grow in aerobic and anaerobic conditions. This requires a high level of flexibility.