Optional anaerobes can perform both >>...

Bacterial requirements for growth include the source

energy, organic carbon (eg sugars and fatty acids) and

metal ions (eg iron). The optimum temperature, pH and the need (or lack of necessary oxygen

) are important. Oxygen requirements obligate aerobes to grow in the presence of oxygen

they can not do

fermentation. Obligate anaerobes do not perform oxidative phosphorylation. In addition, they have killed oxygen, they lack certain enzymes

such as catalase [which breaks down hydrogen peroxide, H,

to water and oxygen], peroxidase [by which NADH + H

] and superoxide dismutase [by which superoxide, O.

converted to H

]. These enzymes detoxify peroxide and

oxygen free radicals formed during metabolism in the presence of oxygen. Aerotolerant >> << anaerobic bacteria that breathe anaerobically, but can survive in the presence of oxygen

. Optional anaerobes can perform both >> << fermentation and aerobic respiration. In the presence of oxygen, anaerobic respiration

generally closed and these organisms are aerobic breathing. Microaerophilic bacteria grow well in low

oxygen concentration, but also kill the higher strattera cost concentrations. Nutrient Requirements These are sources of organic carbon, nitrogen,

phosphorus, sulfur and metal ions, including iron. Bacteria produce small molecules that bind iron (sideroforov eg enterobactin,

mycobactin). Sideroforov (with associated iron), then through an internal >> << receptors in the bacterial cell. The human body as iron transport proteins (eg transferrin). Thus, bacteria that efficiently compete with host iron by >> << poor pathogens. Bacteria can grow in the temperature range from close to freezing to near boiling water

. Those that grow best in the middle of this range

called mezofilov, which includes all human pathogens and opportunists. (Those with lower and higher temperature optima respectively known as

psyhrofily and termofily). Many >> << bacteria grow best at neutral pH, but some bacteria can survive and even grow

quite acidic or alkaline conditions. . << >>