Bacteria What kind of microorganisms are bacteria? Why do we study bacteria? How do we grow bacteria in our lab? How do we count and analyze bacteria?

What kind of microorganisms are bacteria? They are very small, unicellular organisms, that reproduce by fission (splitting) Their range size is 0.1-10 µm. To have an idea, 100 cells are equivalent to the diameter of 1 human hair. As they are so small, we can not see them without a microscope

Why do we study bacteria? Bacteria are naturally everywhere, soil, water, us. Microbiologists work to understand how bacteria live, and through this understanding, to devise ways in which benefits may be increased and damages minimized Bacteria affect many parts of our live in addition to playing a role as disease agents

Why do we study bacteria? Bacteria and agriculture Some legumes live in close association with special bacteria that form structures called nodules on their roots. In these nodules, atmospheric nitrogen (N2) is converted to fixed nitrogen that plants can use for growth. Bacteria and energy Bacteria can decompose much of our waste and transform that in energy such as gas methane Bacteria and bioremediation Bacteria can degrade pollution generated by human activities such as spills, contamination of groundwater, etc Bacteria as pathogens Some bacteria can cause disease to humans.

How do we grow bacteria in our lab? We grow them in reactors containing a liquid that has all the nutrients and food they need at specific temperature Then we treat bacteria in different ways (different antibiotics, disinfectants) and we study how they react to these compounds We use the microscope to see morphological changes (size, appearance, etc) and we also count them to see if possible to inhibit their growth