Micro Organisms


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A slideshow about cell respiration, mirco-organism categories and other information

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Micro Organisms

  1. 1. Nutritional Classification of Micro-organisms Reducing-Power Source Categories Carbons Based Categories Aerobic Respiration Anaerobic Respiration Cell Respiration Stages Oxidase Test Catalase Test Micro-Organisms
  2. 2. Nutritional Classification of Micro-organisms <ul><li>There are more than one way to divide living organisms into different categories. For example, they can be divided into Chemotrophs and Phototrophs depending on the source of energy used in the manufacture of ATP. Chemotophs obtain energy by oxidating chemical compounds while Phototrophs use light as a source. </li></ul><ul><li>Likewise, organisms can be divided into different categories is based on the source of reducing power used. Reducing power is required by all organisms and refers to the electrons used for biosynthesis. </li></ul>http://www.jlindquist.net/generalmicro/102bactnut.html , Wikipedia
  3. 3. Reducing-Power Source Categories <ul><li>Organotrophs are organisms that oxidize organic compounds. </li></ul><ul><li>Organisms that oxidize inorganic compounds are called lithotrophs (which literally translates to “stone eaters”). </li></ul><ul><li>These terms are sometimes applied chemotrophs, thus there are references to Chemoorganotrophs and Chemolithotrophs </li></ul>http://www.jlindquist.net/generalmicro/102bactnut.html , Wikipedia
  4. 4. Carbons Based Categories <ul><li>Carbon is an vital element in all living organisms. So organisms can also be classified based on the nature of their source of carbon. Organisms that use organic compounds to meet their carbon requirements are called heterotrophs. Those that use nonorganic are called autotrophs. </li></ul><ul><li>Chemohetrotrophs are generally organotrophic and so can also be referred to as chemoorganotrophs. These are organisms which use several organic compounds as sources of carbon and energy. </li></ul><ul><li>Chemoautotrophs are generally lithotrophic and so are also referred to as chemolithotrophs. </li></ul><ul><li>These are only some of the categories. Others are Myxotrophs and Phototrophs. </li></ul>http://www.jlindquist.net/generalmicro/102bactnut.html , Wikipedia
  5. 5. Aerobic Respiration <ul><li>Aerobic respiration requires O 2 . It breaks down fuel molecules to gain chemical energy. The O 2 acts as the terminal electron acceptor. The most common food molecules used by cells in aerobic respiration are glucose, amino acids and fatty acids </li></ul><ul><li>Generally, aerobic respiration forms 38 ATP molecules for a single glucose molecule. </li></ul><ul><li>There are three stages to aerobic respiration; Glycolysis, the Kreb’s Cycle and the Electron Transport Chain </li></ul><ul><li>In glycolysis an sequence of enzymes control reactions that break down fuel molecules to a pyruvate. The pyruvate is then oxidized to a substance called acetylcoenzyme A (acetyl CoA). </li></ul>http://www.buzzle.com/articles/aerobic-and-anaerobic-respiration.html , http://science.jrank.org/pages/1331/Cellular-Respiration.html , Wikipedia
  6. 6. Anaerobic Respiration <ul><li>Anaerobic respiration is defined as the breakdown of food substance in the absence of oxygen with a small amount of energy. </li></ul><ul><li>Anaerobic respiration, unlike aerobic respiration doesn’t require oxygen. Instead it has another electron acceptor which replaces the oxygen. </li></ul><ul><li>Often anaerobic respiration can be used interchangeably with fermentation. However, they are not synonymous terms since there are some prokaryotes that can generate all their ATP using an Electron Transport System and ATP synthase. </li></ul><ul><li>There are Obligate Anaerobes, organisms to which the presence oxygen is lethal. There are also Facultative anaerobes which can survive in both oxygenated and deoxygenated environment and can switch </li></ul>http://www.buzzle.com/articles/aerobic-and-anaerobic-respiration.html , http://science.jrank.org/pages/1331/Cellular-Respiration.html , Wikipedia
  7. 7. Cell Respiration Stages <ul><li>Cellular Repsiration takes place within the mitochondria </li></ul><ul><li>In glycolysis an sequence of enzymes control reactions that break down fuel molecules like glucose to a pyruvate. The pyruvate is then oxidized to a substance called acetylcoenzyme A (acetyl CoA). </li></ul><ul><li>In the Kreb’s Cycle the acetyl CoA is broken down to create hydrongren atoms. These hydrogens are energy rich and attach to the oxidized form of coenzyme nicotinamide adenine dinucleotide (NAD - ) turning it into NADH and attaching to another coenzyme called flavin adenine dinucleotide (FAD) turning it into FADH 2 . It is in these cycle that the carbon atoms are used to form CO 2 </li></ul><ul><li>In the Electron Transport Chain stage, the hydrogen rich in energy are separated into protons and electrons. At the beginning, the hydrogen is removed producing NAD - and H + and two electrons. The electrons are moved along the chain of carrier molecules (the ETC) until they are at the end with the O 2 molecules. Here the oxygen is oxidized into H 2 0. The electrons go through a process called Oxidative Phosphorylation . Oxidative Phosphorylation uses energy relased by the elecrons as they pass from the hydrogens down the chain. This energy is used to pump protons across the inner membrane, creating a concentration gradient. At the same time OH - crosses the membrane in the opposite direction. The simultaneous opposite flow of the positive and negative ions create an electrochemical proton gradient. The protons moving down this gradient sets in motion in motion an enzyme which catalyzes the reaction of a phostphate attaching to an ADP molucule, creating ATP </li></ul>http://www.buzzle.com/articles/aerobic-and-anaerobic-respiration.html , http://science.jrank.org/pages/1331/Cellular-Respiration.html , Wikipedia
  8. 8. Cell Respiration Stages Summarized <ul><li>Glycolysis Glucose pyruvate A cetyl CoA </li></ul><ul><li>Kreb’s Cycle A cetyl CoA H + +NAD - NADH </li></ul><ul><li>Electron Transport Chain NADH NAD+ H + +2e H 2 0+ Oxidative Phosphorylation </li></ul><ul><li>Oxidative Phosphorylation ADP+Pi ATP </li></ul>
  9. 9. Oxidase Test <ul><li>There are a variety metabolic pathways and a variety of tests to identify them. The Oxidase test is one of them. It is used to see if a bacterium produces certain cytochrome c oxidase. </li></ul><ul><li>Two of the reagents used is called N,N,N′,N′ -tetramethyl- p -phenylenediamine (TMPD) and N,N -Dimethyl- p -phenylenediamine (DMPD). TMPD is also a redox indicator. When TMPD is oxidised, it turns a dark blue to maroon colour and when it reduced it loses it colour. The reagent is soaked into an disk </li></ul><ul><li>To carry out the Oxidase test, wet the dick with approximately four inoculating loops of deionized water. Then use a loop to transfer a large amount of bacteria to the wet disk. Watch the disk for up to three minutes. If the site of inoculation turns dark blue to marron to an almost black colour, the result is positive. No colour change means it is negative. </li></ul><ul><li>It is possible to perform the test on agar plates. After colonies have grown on the agar, simply add a few drops of of the reagent DMPD to the surface of each organism that is to be tested. Positive test will have a colour change to pink, through marron and to black within 30 seconds. A negative test will have a light pink or no colour. </li></ul>
  10. 10. Catalase Test <ul><li>Catalase is a common enzyme, found in the almost all living organisms. One of Catalase’s functions is to break down hydrogen peroxide (H 2 O 2 ) to water and oxygen. Catalase is one of the efficient enzymes known. A single molecule of catalase can breakdown millions of molecules of H 2 O 2. </li></ul><ul><li>The catalase test is carried out by placing a drop of H 2 O 2 then smearing a sample into the H 2 O 2 . If bubbles or froth appear, then the organism is catalase positive. Otherwise it is catalase negative. </li></ul><ul><li>On it’s own, the catalase cannot identify the organism. All it does is simply identify whether or not it produces the enzyme catalase </li></ul>