Microbiology Outline

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  • Topic: Bacteria, Photosynthesis, Eukaryote
  • Pages : 6 (1119 words )
  • Download(s) : 240
  • Published : September 26, 2012
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Energy Categories of Microorganisms
Phototrophs- Use light as an energy source
Chemotrophs- Use ether inorganic or organic chemical as energy source. Carbon Source. (Photosynthetic organisms such as plants, algae etc.) Autotrophs- Use carbon dioxide as their sole source of carbon Heterotrophs- Organisms that use organic compounds other than CO2 as their carbon source (humans, animals, fungi etc) Energy/carbon categories

-Photoautotroph-are organisms (such as plants, algae, cyanobacteria, purple and green sulfur bacteria) that use light as an energy source and CO2 as a carbon source. -Photoheterotrophs,- like purple nonsulfur and green nonsulfur bacteria, use light as an energysource and organic compounds other than CO2 as a carbon source. Chemoheterotrophs use chemicals as an energy source and organic compounds other than CO2 as a carbon source. All animals, all protozoa, all fungi , and most bacteria are chemoheterotrophs. chemoorganoheterotroph- organism that requires organic substrates to get its carbon for growth and development, and that produces its energy from oxido-reduction of an organic compound. Chemoorganoautotroph- An organism that obtains energy from organic compounds and carbon from CO2. Chemolithoautotroph- An organism that obtains energy from inorganic compounds and carbon from CO2. Characteristics of the classic growth curve.

Lag phase- during which the bacteria absorb nutrients, synthesize enzymes, and prepare for cell division. The bacteria do not increase in number during the lag phase. Seen with old inoculum

Damaged cells
Transfer from nutrient-rich to nutrient-poor media Exponential phase (Logarithmic growth phase)-the bacteria multiply so rapidly that the number of organisms doubles with each generation time. Cells in healthiest state

Midexponential cells
Rates of exponential growth can vary
Growth rate is the greatest during the log phase.
Stationary Phase- It is during this phase that the culture is at its greatest population density. Exponential growth will tail off
Limiting nutrients
Build up of waste products
No net increase or decrease in cell number
Cryptic growth
survival genes
Death Phase- As overcrowding occurs, the concentration of toxic waste products continues to increase and the nutrient supply decreases. The microorganisms then die at a rapid rate .
Oxygen relationships and classification categories
Aerobe- organisms that require oxygen for life and reproduction. Tolerate full O2 tensions (21%)
obligate aerobes -require an atmosphere containing molecular oxygen in concentrations comparable to that found in room air (i.e., 20 to 21% O2). Anaerobe- organisms that do not require oxygen for life and reproduction. Aerotolerant anaerobes- does not require oxygen, grows better in the absence of oxygen, but can survive in atmospheres containing molecular oxygen (such as air and a CO2 incubator). Obligate anaerobes- an anaerobe that can only grow in an anaerobic environment (i.e., an environment containing no oxygen). Microaerophiles- Microaerophiles (microaerophilic aerobes) also require oxygen for multiplication, but in concentrations lower than that found in room air. Tolerance less than 21%

Limited capacity for respiration
O2-labile component
Faculative Anareobes- are capable of surviving in either the presence or absence of oxygen; anywhere from 0% O2 to 20 to 21% O2.
Characteristics of the different groups of algae
-Diatoms (Bacillariophyta): unicellular; free-living, photosynthetic autotrophs; some colorless heterotrophs; freshwater and sea water, Chromista -2 part frustules
-nucleus- central in cytoplasm
-chloroplasts- inside rough...
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