2. 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.
3.
4. 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.
5. 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.
6. 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
7. 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.
8. 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
9. 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 .
10. 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)
11. Anaerobic bacteria use inorganic substances as a final electron
acceptor.
