Microbiology Fall 2014 Exam 1 Study Guide Microbiology the study of organisms e g bacteria fungi algae protozoa and viruses too small to be seen with the naked eye Includes their role in human diseases and beneficial processes It is a great paradox because we need bacteria ad microbes to live but they can also be incredibly harmful to our health Characteristics of Life 1 Composed of cells 2 Metabolism 3 Growth increase in the mass of biological material 4 Reproduction 5 Genetic variation allowing the possibility of evolution 6 Response to external stimuli and adaptation 7 Homeostasis An organism may not exhibit all of these traits at all times definition of life must be applied holistically E g Are endospores alive Are viruses alive Chemical Make Ups of Cells Macromolecules Polypeptides aka PROTEINS o Polymers of amino acids o Most abundant class of macromolecules o Some function as enzymes Nucleic acids o Polymers of nucleotides o Includes DNA and RNA o Individually composed of a sugar molecule deoxyribose in DNA and ribose in RNA a phosphate group and one of 4 nitrogen containing bases A C T U G o DNA stores genetic information o RNA can serve structural or catalytic functions as well as production of polypeptides main Lipids o Hydrophobic hydrocarbon molecules o primary role is to form the plasma membrane structural purpose Polysaccharides o Polymers of monosaccharides sugars o Composed entirely of carbon hydrogen and oxygen Cm H2O n o Structural uses e g chitin and cellulose and energy storage e g glycogen and starch Microbiology Fall 2014 Exam 1 Study Guide Woese Fox 3 Domain 4 Kingdom System Places prokaryotes on separate lineages based on rRNA data Bacteria Nuclear membrane No Membrane bound organelles Rare found in a few species Archaea No Rare found in a few species Cell Wall Plasma membrane Found in nearly all species made of peptidoglycan Similar to Eukarya Different from Found in nearly all species made of various materials RNA Polymerase Single polymerase Histones Histone like proteins either bacteria or eukarya Single polymerase eukaryal like RNA pol II Yes Eukarya Yes Found in all species multiple distinct types Found in some species made of various materials Similar to Bacteria Three main polymerases RNA pol I II and III Yes Morphology 1 Morphologies a Spherical Coccus pl cocci i Determined by plane of division and separation 1 Diplococci pairs 2 Streptococcus long chains e g Streptococcus pyrogenes 3 Staphylococcus grapelike clusters e g Staphylococcus aureus 4 Tetrad Micrococcus division in two planes b Rod Shaped Bacillus pl Bacilli i E g Bacillus anthracis Escherichia coli c Comma shaped Vibrio pl vibrios i E g Vibrio cholera d Spiral Spirillum pl spirilla i E g Treponema pallidum e Pleiomorphic i Varied shapes ii Typically have no cell wall iii Generally float between rod and sphere shapes Microbiology Fall 2014 Exam 1 Study Guide 2 The size of bacteria can vary greatly a About 0 5 5um in length smaller than eukaryal cells i Most must be observed with a microscope b Why so small i More adaptable ii Nutrients more readily available and can eliminate waste more effectively iii Can replicate more quickly iv Faster metabolic rate can turn genes on and off quickly to adapt to ever changing environments 1 VERY metabolically flexible Cultivating Microorganisms primarily of Macromolecules proteins lipids carbohydrates nucleic acids are composed o Carbon Nitrogen Phosphorus Sulfur Oxygen Hydrogen CHOPSN o These are required in relatively large amounts Macroelements that do not make up macromolecules o K enzymes o Ca heat resistance of endospores o Mg enzyme cofactor stabilizes ribosomes and membranes o Fe ATP synthesis via electron transport o Na and Cl osmotic balance Energy electrons and carbon Carbon Backbone of all organic components present in a cell Carbon sources often provide H O and electrons Electrons are involved in energy production and the reduction of CO2 to form organic molecules o CO2 is not an organic molecule It has no C H bonds Therefore you cannot get all necessary organic building blocks C H O and electrons from CO2 Must know where and organism gets all three of these in order to determine its metabolic pathway Microbiology Fall 2014 Exam 1 Study Guide o Phototrophs obtain energy from light o Chemotrophs oxidation od organic or inorganic compounds acts as the Energy energy source Electrons o Lithotrophs Electrons come from reduced inorganic molecules H2 gas elemental sulfur Literally rock eaters o Chemotrophs Electrons come from reduced organic molecules e g glucose Carbon o Heterotrophs Use reduced preformed organic molecules as their C source Cannot synthesize their own organic carbon compounds Very flexible can use ALL naturally occurring organic molecules Actinomycetes soil bacteria can degrade paraffin and rubber Certain microbes can degrade pesticides Often live in communities and use co metabolism the waste of one is the nutrients for another The more reduced the organic carbon source is i e the more electrons it carries the higher its energy content will be Lipids have more energy than carbs Microbiology Fall 2014 Exam 1 Study Guide o Autotrophs Use CO2 as their sole or principle carbon source Problems Lacks hydrogen o These types of organisms are most likely to be found in aqueous environments where there is a lot of H2O CO2 is the MOST OXIDIZED form of carbon and so has the least amount of energy and cannot donate electrons during oxidation reduction reactions o Backbone of all organic components present in a cell o Carbon sources often provide H O and electrons o Electrons are involved in energy production and the reduction of CO2 to form organic molecules CO2 is not an organic molecule It has no C H bonds Therefore you cannot get all necessary organic building blocks C H O and electrons from CO2 The majority of microorganisms are Photolithoautotrophs photoautotrophs Chemoorganoheterotrophs chemoheterotrophs o Majority of pathogens human like feeding conditions Not always so clear cut because bacteria tend to have great metabolic flexibility this is important when living in an environment where the conditions change frequently Factors Affecting Growth 1 Nutrient type what can a microbe use a Prototrophs synthesize all needed macromolecular precursors from a single carbon source and inorganic molecules b Auxotrophs cannot synthesize all needed precursors from a single carbon source c Nutrient concentration i These are generally mutants