Chapter 4 of Microbiology
Chapter 4 of Microbiology 2300
Popular in Microbiology 2300
Popular in Microbiology
This 4 page Class Notes was uploaded by Lauren Dennis on Thursday September 8, 2016. The Class Notes belongs to 2300 at Georgia State University taught by Dr. Fuhua Lu in Fall 2016. Since its upload, it has received 16 views. For similar materials see Microbiology 2300 in Microbiology at Georgia State University.
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Date Created: 09/08/16
Chapter 4: Microbial growth Energy Source: o Photoautotroph:sunlight o Photoheterotroph: sunlight o Chemolithoautotroph: Inorganic o Chemoorganoheterotroph: Organic Carbon Source: -CO2 Organic Compounds CO2 Organic Compounds Nutritional Factors o Required elements: C, O, H, N, S, K, Magnesium, Calcium, Iron o Organisms based on carbon use: Heterotrophs: organic carbon Autotrophs: inorganic carbon (CO2) o Trace Elements: small amounts the organism needs Cobalt, Zinc, Copper, molybdenum, mangnesium Growth Factors o Some cannot synthesize cell constituents The elements have to be added to the organism o Can display wide variety of factor requirements Element Function C, O, and H Component of amino acid, lipids, nucleic acids, and sugars N Component of amino acids and nucleic acids Sulfur Component of some nucleic acids Phosphorous Component of nucleic acids, membrane lipids, and ATP Potassium, Magnesium, and Required for the function of Calcium certain enzymes Bacterial Growth in Lab o “Closed” Batch System: no input of nutrients population grows in a predictable, steady growth o Growth Curve Lag phase: no real growth Log or exponential phase: huge growth of the organism Produce metabolites that enhance survival Static phase: Death phase: Prolonged decline: N t N xo2 n Prokaryotes divide by binary fission Colony growth on a solid medium Cells compete for resources o They grow exponentially and then compete for nutrients Position in the colony determine the resource availability o On the edge: have little competition/ high oxygen stores o In the middle: high population density Increased competition/ low oxygen stores Continuous Culture: Exponential growth can be sustained by the use of chemostat o Continually drips nutrients into the colony o Release of equal waste Growth in Nature o Biofilm begins when planktonic bacteria attach to surfaces, Others: attach and grow on the initial layer Contains open channels for movement of nutrients and waste Cells within cause disease o Resist immune response and antimicrobials o Treatment becomes difficult Bioremediation is beneficial use of biofilm o Degradation of organic waste that cannot be removed o Interactions of mixed microbial communities Prokaryotes live in mixed communities Many interactions are cooperative o Waste of one is beneficial for another Cells compete for nutrients o Synthesize toxic substances to inhibit growth of the competition Environmental Factors: o Temperature Psychrophite: -5C to 15C Artic environments Psychotroph: 20C to 30C Food spoilage Mesophile: 25C to 45C Disease causing Thermophile: 45C to 70C Hot Springs Hyperthermophiles: 70C to 110C Archaea or Hydrothermal vents o pH bacteria can survive in various pH’s Neutrophiles pH of 5 to 8 optimum near neutral Acidophiles pH below 5.5 neutral internal pH, pumps out protons Alkalophiles pH above 8.5 maintains by sodium ion exchange o external ion sodium for external protons o Water Dissolved salts, sugar makes water unavailable to cell Used to preserve food from bacteria growth Some can withstand high concentrations of salt Halotolerant: withstand up to 10% Halophiles: require high salt concentrations Marine bacteria
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