Bacterial physiology All bacteria have three req for growth 1 – source of C ( for making cellular constituents). 2 – N (for making proteins). 3 – source of energy (ATP) for carrying out cellular functions Small amounts of molecules eg. PO4 for nucleic acids,

Bacterial physiology Bacteria require O2, H, C, inorganic ions, organic nutrients O2 & H from water Carbon – Autotrophs –non-parasitic bacteria, use CO2 as carbon source. Heterotrophs- parasitic bacteria, use organic substances as source of CO2 & energy.

Bacterial physiology Inorganic ions- N, S, PO4, Mg, K, Organic nutrients- carbohydrates, aminoacids, vitamins, purines & primidines Energy production – Various mech used to generate energy from carbon sources – 1 –Aerobic respiration –Krebs or TCA cycle -metabolic process in which molecular O2 serves as the final electron acceptor of electron transport chain. O2 is reduced to H2O. Used by all aerobic & facultative aerobic bacteria

2 -Anaerobic respiration – Bacterial physiology 2 -Anaerobic respiration – Metabolic process in which inorganic compds(NO3, SO4) other than O2 serve as final electron acceptor. Used by facultative organisms, obligate anaerobes.

3 -Fermentation –anaerobic process. Bacterial physiology 3 -Fermentation –anaerobic process. Organic metabolic intermediate derived from fermentable substrate(sugars) serve as the final electron acceptor. Fermentation of glucose to lactic acid –pyruvic acid is final electron acceptor. Fermentation of glucose to ethanol–actaldehyde(a derivative of pyruvic acid) is final electron acceptor.