Monday, August 25, 2008





Other feeders

Photosynthetic microbes

Decomposing microbes

CO2 as carbon source

Organic carbon source

Environment bacteria , protist, fungi


Don't cause disease

Cause infection

Symbiosis: normal flora live in peace with us and same time benefit us .


Parasite: benefit from the host (don't kill the host)


Microbial Nutrition




Organic compound required in large amount composed of

Proteins, carbohydrates, lipids








Micronutrients or Trace Elements


Elements and gases required in small amounts. Inorganic, metals (iron, manganese, zinc, nickels), and Gases CO2, O2, N2.

Water composes the remaining 70% of cytoplasm. More water more opportunity to growth.







Energy Production in Heterotrophs




Sugar ----> acid or alcoholic/ CO2 + ATP (small amount) NOTE: slow process, no O2 required


Aerobic Respiration


Sugar + Oxygen -----> ATP + CO2 + H2O


Anaerobic Respiration


Sugar + nitrate (NO3-) ----> ATP + nitrite NO2+

Sugar + sulfate (SO42-)----->ATP + hydrogen sulfate (H2S)


Temperature Requirements


Psychrophile: microorganism is capable to growth at 0o C optimum temperature is 15oC

Mesophile: organism that growth at intermediate temperature

Thermophile: organism growth at temperature greater than 45oC


pH Requirement


Acidophile: organism that live in pH 1-5

Neutrophile: organism that live in pH 5-9

Alkaliphile: organism that live in pH 8-12


Oxygen Requirement


Facultative Anaerobe: prefer oxygen if available. If not change to fermentation.

Microaerophile: prefer small amount of O2. It is present in mucous membrane

Capnohile: prefer CO2 concentration. It's presented in lungs

Aero tolerant Anaerobe: don't utilize O2

Obligate Anaerobe: organism that don't tolerate O2

Obligate Aerobe: need O2


H2O + O 2

Kill anaerobic bacteria


Osmotic Pressure in Bacteria

Hypertonic Solution: water follows out of cell membrane collapse but wall remains=plasmolysis


Hypotonic Solution: water goes inside the cell until cell explode. Gram negative


Isotonic Solution: water flows equally



Salt is important in water movement

Halophile: salt loving

Osmophile: hypertonic loving (diabetes)



Bacillus: survive hot temperature and form spores produce anthrax


Passive Transportation


Base on concentration

Water and salt go on different directions

No energy needed, moving with concentration high to low


Simply diffusion (O2 CO2) pass across bilayer

Facilitated diffusion (sugar, ions) no energy required, use protein channels

Osmosis (water) where is salt, water follows


Active Transport Across Membrane


Energy needs

Going against concentration


Group translocation the sugar goes in and attach to a phosphate (it's to big to go out). How bacteria repairs themselves and how they retain sugar.

Endocytosis and exocytose eukaryotes only


Binary Fission


A sexual reproduction

Chromosome replicates

Cytoplasm divides

Daughters cell are identical to each other and to former parent cell


Typical Growth


Lag phase


Exponential phase

Very quick growth you have symptoms

Stationary phase

No increase in number
*all bacteria follow this phases the only variable is the time

Death (decline) phase

As rapid as exponential phase. You need your white cells and antibiotics



Quorum Sensing


When the bacteria sense that there are more around. They start to produce the toxin to kill the other cell. However that toxin only damage US.



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