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10/10/12 Prokaryote Iden1fica1on Biology: Size varies What is Life? The sizes of bacteria and archaea vary. Mycoplasma cells (left) are about 0.5 µm in diameter, while Thiomargarita namibiensis cells (right) are about 150 µm in diameter. Properties of Life Cellular Structure: the unit of life, one or many Metabolism: photosynthesis, respiration, fermentation, digestion, gas exchange, secretion, excretion, circulation – processing materials and energy Shape varies The shapes of bacteria and archaea vary from rods such as Bacillus anthracis (left) and spheres to filaments or spirals such as Rhodospirillum. In some species, such as Streptococcus faecalis (right), cells attach to one another and form chains. Growth: cell enlargement, cell number Movement: intracellular, movement, locomotion Mobility varies A wide variety of bacteria and archaea use flagella (left) to power swimming movements. These cyanobacterial cells (right) move by gliding across a substrate. Reproduction: avoid extinction at death Behavior: short term response to stimuli Evolution: long term adaptation Figure 28-13 Page 578 How prokaryotes obtain energy to make ATP • Phototrophs – From sunlight • Chemoorganotrophs – From organic compounds • Chemolithtrophs hHp://www.sciencemadesimple.com/leaves.html Nutrients provide either: An energy source A carbon source Everything else – From inorganic compounds Chemotrophs hHp://www.adop1onhealing.com/DontEverGiveUP.html We can create categories based on metabolism 1 10/10/12 Prokaryote Nutri1on How prokaryotes obtain carbon Nutrition Mode Photoautotroph • Heterotrophs – CO2, CH4 – Consump1on of other organisms hHp://www.sciencemadesimple.com/leaves.html hHp://www.adop1onhealing.com/DontEverGiveUP.html Chemoautotroph Nutrition Mode Photoautotroph • Cyanobacteria Photoheterotroph Chemoheterotroph Energy Source Carbon Source Light Nutrition Mode CO2 Chemoautotroph bacteriochlorophyll hHp://commtechlab.msu.edu/sites/dlc-‐me/zoo/zdrs0232.jpg light CO2 + H2S S2 + CH2O Inorganic chem CO2 • Nitrosomonas -‐ nitrifica1on (forms nitrite) 2 CO2 + NH4+ NO2-‐ + 2 CH2O light CO2 + H2O O2 + CH2O chlorophyll • Purple-‐sulfur bacteria Energy Source Carbon Source hHp://www.ctlaboratories.com/Home%20Page/Waste%20Water.html • Autotrophs Energy Source Carbon Source 2 10/10/12 Nutrition Mode Energy Source Carbon Source Photoheterotroph Light Organic chem Light C2H4O2 2 CH2O Bacteriochlorophyll a Examples: purple non-‐sulfur bacteria, green non-‐sulfur bacteria, and heliobacteria Nutrition Mode Chemoheterotroph Energy Source Carbon Source Organic chem Organic chem • Escherichia coli and most eukaryotes including plants. CH2O + O2 CO2 + H2O + ATP Carbohydrate provides both the energy source and the carbon source http://www.acadweb.wwu.edu/courses/envr429-rm/Robin/images/envr429/1_rhodospirillum_600x.jpg Prokaryote Nutri1on Nutrition Mode Energy Source Carbon Source Yes Photoautotroph Light CO2 Chemoautotroph Inorganic chem CO2 Photoheterotroph Light Organic chem Chemoheterotroph Organic chem Organic chem Fixes CO2? No All of these nutritional modes are found among prokaryotes! Eukaryotes are not as diverse in their nutritional modes. hHp://en.wikipedia.org/wiki/File:Troph_flowchart.png 3 10/10/12 Ques1on What do you call a prokaryote that obtains carbon from the atmosphere and energy from the sun? Photoautotroph What do you call an organism that obtains carbon by inges1on and then gets energy from the breakdown of sugars? • Prokaryotes come in all shapes and sizes, but those characters are not enough to iden1fy the thousands of bacterial species known • Scien1sts iden1fy bacteria based on their metabolism – Sugars, amino acids, nitrogen sources, gas produc1on Chemoheterotroph Iden1fying bacteria based on metabolism hHp://www.iit.edu/magazine/spring_2009/sulfur_ea1ng_bacterium.shtml Prokaryote Iden1fica1on hHp://adilclinic.blogspot.com/2011/07/macconkeys-‐medium-‐composi1on-‐and.html Iden1fying bacteria based on metabolism hHp://biologyofmicroorganisms.blogspot.com/2010_09_01_archive.html hHp://indianapublicmedia.org/eartheats/food-‐poisoning-‐crime/ 4 10/10/12 Enterotubes hHp://www.superstock.co.uk/stock-‐photos-‐images/1598R-‐183690 hHp://www.mesacc.edu/~johnson/labtools/Dbiochem/ent.html Microscan Plate New Fron1ers -‐ Metagenomics • The study of gene1c material recovered directly from environmental samples – Also called direct sequencing • Our culture techniques are specific to bacteria that cause disease (37 oC, nutrient-‐rich agar) • But less than 1% of bacterial species can be cultured in this way “Viable but not cultureable” Figure 28.9 pg 575 5 10/10/12 Metagenomics at work Microbial communi1es of public restroom surfaces hHp://cymeandcys1dium.com/?p=451 6
