Bacterias

ProkaryotesAlvaro Lafuente Lahoz

 Eubacteria:  Are most common species Archaebacteria:  Are strange species that inhabites hostil enviroments. This type of Bacteria appeared when the earth was very young.  They use to live in extremely salty enviroments or very warm enviroments.

 They occur in several stages termed lag, log, stationary, and death.  Lag phase: active metabolic activity occurs involving synthesis of DNA and enzymes, but no growth.  Log: The bacteria grows  Stationary phase: The growth rate slows, involves the establishment of an equilibrium in population numbers  Death: The populations decrease.

 The minimun temperature is the one in which a particular species will grow. The maximun temperature is the one in which they will grow The temperature in which they will grow better is called optimum growth temperature.

 Mesophiles: preffer warm temperatures. Optimun temperature is 25ºC and 40ºC. Like the ones in our body. Psychrophiles: preffers cold temperatures. Temperatures between 0ºC and 15ºC. This ones live in oceans depth. Thermophiles: Live in very hot enviroments with temperatures between 50ºC and 91ºC

 pH also plays a role in determining the ability of bacteria to grow in particular environments. Bacteria grow optimally within a range of pH between 6.7 and 7.5. Acidophiles, however, prefer acidic conditions, they can survive at pH 1 Vibrio cholera, the cause of cholera, can thrive at a pH as high as 9.0.

 Osmotic pressure is another limiting factor in the growth of bacteria. They are about 80-90% water. They obtain most of their nutrients from the environments. The cell wall in prokaryotes protect against changes in osmotic pressure

 Bacterias requieres a variety of elements in addition with water and the correct salt balance.  Hydrogen, and nitrogen, sulfur and phosphorus, potassium, iron, magnesium and calcium. Growth factors, such as vitamins and pyrimidines and purines (the building blocks of DNA). Carbon is the fundamental building block of all the organic compounds needed by living things. ◦ Chemoheterotrophs are bacteria that use organic compounds such as (proteins, carbohydrates and lipids as their carbon source), and which use electrons from organic compounds as their energy source. Bacteria are Chemoheterotrphs  Chemoheterotrophs obtain the carbon from carbon dioxide ◦ Saprophytes are heterotrophs that obtain their carbon from decaying dead organic matter. ◦ Phototrophs use light as their primary source of energy.  Use organic compounds to get carbon source. Some bacteria do not need oxygen, depend of the type of metabolism, aerobic or anaerobic .

 Aerobic bacteria us oxygen to break down pyruvic acid (It is the product in carbohydrate and protein metabolism). This procces release much more ATP during glycolysis. (Cell respiration is how cells get the energy from glucose, this produce ATP that is the energy currency)

 Anaerobic bacteria use inorganic substances as a final electron acceptor.

 http://science.jrank.org/pages/714/Bacteria.html

Bacterias

by Alvaro Lafuente on Dec 23, 2011

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Bacterias — Presentation Transcript