BIOL 2070 Lecture Notes - Lecture 3: Microscope Slide, Nitrifying Bacteria, Algae
23 Apr 2016
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Students should be able to : nutritional and environmental factors, list and briefly describe the basic physical and chemical requirements for microbial growth. Minimum growth temperature, optimum growth temperature, maximum growth temperature. Psychotrophs (23); spoilage bacteria; mostly no pathogens grow at refrigerator temps. Most bacteria grow well between 6. 5 and 7. 5. Molds and yeast will grow over a greater ph range than bacteria (optimal: 5-6) Usually when grown bacteria produce acids must be neutralized by use of buffered medium. Hypertonic environment (cell plasmolysis; cell pulls away from the cell wall) Salt can be used to preserve foods. Grow in salt concentrations of up to 2% (even up to 15%) Half of the dry weight of a typical bacteria is carbon. Protein synthesis requires nitrogen and well as some sulfur. Synthesis of dna and rna require nitrogen, phosphorus. Some bacteria break down protein-containing material and reincorporate the amino acids. Some important bacteria can fix nitrogen (n2)
