MICROBIOLOGY OUTLINE Exam 2 CHAPTER SEVEN all Microbial Nutrition and Growth I Microbial Nutrition Elements Major bioelements C H N O P S Minor bioelements Ca Na K Cl Fe Micronutrients Mn Zn Cu others metals used for a few types of chemical reactions too much of these can be toxic Molecules Organic Biomolecules Types 1 Proteins 2 Carbohydrates 3 Lipids 4 Nucleic Acids Many are macromolecules Synthesized from smaller inorganic or small organic molecules Growth Factors organic molecule that cannot be synthesized and must be taken into the cell from the environment Vitamins are growth factors Vitamin A you can t synthesize must get it from diet II How do Microbes Acquire Nutrients Transport across cell membrane Small inorganic and organic molecules Salt ions simple sugars amino acids Ca Na K Carbon dioxide Most bacteria and Fungi many protozoa transport across cell membrane Acquiring Nutrients from large Molecules Bacteria and Fungi and some protozoa secrete enzyme outside of cell degredative enzyme enzyme breaks down large molecule into smaller molecules of nutrients that can be transported across membrane Phagocytosis and Injection Some Protozoa Particle or liquid sits in vesicle until digested once degraded into smaller particles vesicle releases the particles Pinocytosis engulfing liquid Phagocytosis engulfing particles III Metabolic Categories Autotroph a microorganism that requires only inorganic nutrients and whose sole source of carbon is carbon dioxide Use CO2 Self feeder Heterotroph an organism that relies upon organic compounds for its Other feeder Use organic materials to get CO2 carbon and energy needs Photoautotroph dioxide chiefly for its carbon needs energy and carbon dioxide for its carbon also called a chemolithotroph Microorganisms that derive their nutritional needs from organic compounds an organism that utilizes light for its energy and carbon an organism that relies upon inorganic chemicals for its Chemoheterotroph Chemoautotroph IV Types of Chemoautotrophs 1 Predators actively capture food some protozoa few bacteria and fungi usually takes place in soil 2 Saprobes decomposers grow on dead material saphoritic 3 Commensals use living organisms to get food cell bacteria protozoa fungi 4 Parasites harms organisms they are growing on or in pathogens bacteria fungi protozoa viruses V Bacterial Growth Microbiologists measure the growth of a population Types of growth 1 Open system grow unlimited nutrients no build up of waste products VI Method of Reproduction 2 Closed system system where some microbe has unlimited space to limited space limited nutrients waste product build up Binary Fission bacteria splits to reproduce VII Growth in Open System Doubling or exponential growth 1 2 4 8 16 32 Doubling time generation time time required for the population to double in size VIII Growth in Closed System standard normal growth curve gearing up phase 1 Lag phase 2 Exponential Growth Phase 3 Stationary Phase 4 Death Phase IX Methods of Enumeration 1 Standard Plate Count more cells dying 2 Turbidity Colony forming units way of estimating growth in a liquid doubling growth where cells start to die the more bacteria there are in a flask the cloudier the water is more turbid Spectroturtometer instrument that measures the turbidity of liquids 3 Direct Count Microscopy 4 Flow Cytometry look under microscope count number of cells on grid look at how many cells by way of an electric detector hooked up to a computer used a lot in hospitals can count blood cells X Factors Influencing Growth Nutrient limitation waste accumulation physical space Other physical and chemical forces temperature oxygen levels hydrogen ions pH Osmotic Forces salt concentration growth response microbes grow best optimum growth at one point of an environmental factor XI Temperatures Effects on Growth Enzymes chemical reactions in body effects rate of catalysis higher temperature higher rate twice as fast per 10 degrees C high temperatures will eventually degrade proteins and enzymes XII Membrane Fluidity how easily molecules move around in membrane The higher the temperature the lower the fluidity High temperatures melt disintegrate membrane XIII Temperature Ranges for Microbial Growth 0 degrees C freezing point of water 100 degrees C boiling point of water Categories of Microbial Growth 1 Psychrophile cold loving have optimum growth at very cold levels o Best around 4 degrees C 2 Mesophile mid temperatures mid temperature loving have optimum growth at o Best around 37 degrees C human body temp 3 Thermophile hot loving o Best around 65 70 degrees C 4 Hypothermophile very hot temperatures extreme heat loving optimum growth at o Best around the boiling point of water 100 degrees C Chlamydomonas nivalis a Eukaryotic psychrophile protozoa XIV Oxygen s Effects of Microbial Growth Oxygen is needed for energy metabolism cellular respiration by some microbes Must be able to deal with toxic 02 derivatives Super oxides peroxides others Have enzymes to remove toxic derivatives Superoxide dismutase Catalae and peroxidase Other microbes use alternate energy pathways that do not require oxygen fermentation and anaerobic respiration Oxygen not required or may even be toxic to microbe Lack of dismutase and catalase enzymes XV Determining Oxygen Requirement High 02 at the top of tube and no 02 at the bottom of the tube see where bacteria growth occurs in the liquid oxygen preference Study FIGURE likes high 02 levels atmospheric levels can grown without 02 but grows very 1 Obligate Aerobe 2 Faculative Anaerobe well with high 02 3 Aerotolerant Anaerobe preference for particular level 4 Strict Anaerobe can grown without 02 but no needs reduced to no 02 to grow XVI Other Environmental Factors Influencing Growth Hydrogen ion concentration pH 1 Alkaphile alkaline or basic conditions 2 Acidophiles acidic conditions Salts Halophiles grow at 15 22 salt concentration Normal salt concentration 0 9 concentration for microbial growth Pressure Barophile organism that grows at higher than normal pressures Radiation Has harmful affect on most organisms XVII Growth in Aquatic Environments Planktonic free floating Biofilms A microbial community of cells and extracellular matrix attached to a surface Implies close associations and interactions among microbes in the biofilm Most times found on rocks etc also in human body Medical Implications Dental disease Bacterial endocarditis disease on lining valves of heart Osteomylitis inflammation of