Biochemistry Questions / Explain the metabolic flexibility of E. coli in aerobic conditions, emphasizing the role of Ndh and Cyd in respiration. How does the presence of these complexes enhance the survival and infection chances of pathogenic bacteria?

E. coli has a high level of metabolic flexibility, allowing it to survive in many different growth conditions. As a facultative anaerobe, it is capable of using different bacterial electron transport complexes (such as Ndh and Cyd) to allow ATP synthesis in a range of conditions. Some electron transport complexes are more resistant to reducing conditions, for instance.

Being able to grow successfully in a wide range of conditions increases the chances of successful infection in pathogenic bacteria, due to the ability to use different electron acceptors to maintain a redox balance. This increases the likelihood of an electron acceptor being present, allowing the electron transport chain to occur (which is where the most ATP is synthesised in respiration).

E. coli is able to express different electron transport complexes for specific conditions, ensuring it is using the most efficient complexes possible.