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Meet the Microbes!!. Hina´s magical mystery Microbiology lab!. As you watch the film clip. Ask yourself the following questions... What THREE words come to mind when you first see the flat Why do you think James´s flat makes you feel the way you do?
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Meet the Microbes!! Hina´s magical mystery Microbiology lab!
As you watch the film clip.... Ask yourself the following questions... • What THREE words come to mind when you first see the flat • Why do you think James´s flat makes you feel the way you do? • What health risks are posed by keeping the flat in this condition?
Now look at these pictures... In groups list 5 differences between them!
What is microbiology? • Discuss the word with the person next to you! • A little introduction! • So what are we doing this session? a)learning ASEPTIC technique b)learning how to CULTURE bacteria c) understanding how to classify bacteria
autoclave Working with micro-organisms To produce useful products, uncontaminated cultures of microbes are required. This requires certain precautions and sterile techniques to be used.
Using micro-organisms Micro-organisms can be grown by man. They need certain nutrients which are often contained in an agar medium: • carbohydrates (energy source) • mineral ions • sometimes +protein, vitamins This is poured into a petri dish. Contamination Is when unwanted, possibly harmful microbes grow. You don’t want this to happen.
Microbiological techniques 1 2 3 4 5 Aberdeen University Lab coat to protect clothing Microbes not carried out Hands washed before & after, gloves worn Microbes not carried out Smooth, non-absorbent work surface (plastic) cleaned with disinfectant before & after Sterile petri dishes of nutrient agar ready Autoclave / pressure cooker to sterilise glassware (>120oC, 20min) Less chance of unwanted microbes getting in (contamination) Microbes killed Microbes killed
6 7 Lid held over petri dish during inoculation Techniques (continued) Wire loop & bottles flamed before use Microbes killed Less chance of unwanted microbes getting in
8 Bin lined with plastic bag for safe disposal of used materials by autoclaving 9 Inoculated dish sealed with tape Prevents microbes getting in or out Prevents microbes getting out. Microbes killed
Now it´s your turn! Find a partner Decide what aspects of bacterial culture you are going to investigate e.g. The difference between soap and disinfectant Effectiveness of handwashing? Bacteria from different parts of your body Effect of chemicals on bacterial growth Anything else you can think of! Prepare your work surface and agar plate Innoculate! Seal your petri dish and don´t forget to label it with your names and the date Re-sterilise your work surface Wash your hands!
Classificationis the grouping together of things on the basis of features they have in common.
In 1996 scientists found the reasons for the reclassification of living organisms into three domains. • Large collaboration of scientists deciphered the full DNA sequence of every gene of bacteria called Methanococcusjannaschii. • This archaebacterium lives at 85oC, a temperature lethal for regular bacteria as well as multicellular plants and animals. • Only 44% of this archaebacterium genes resemble those in eubacteriaor eukaryotes.
Differences between organisms of three domains: • Histones – proteins associated with the three dimensional structure of chromosomal DNA, present only in eukaryotic cells. • Introns – segments of non-coding DNA within genes that are removed before translation • Size of ribosomes – bacterial ribosomes (70S) – smaller than eukaryotic ones (80S). • Structure of cell walls • Structures of cell membranes
Classification of Bacteria • Archaebacteria: extremists • Eubacteria: • Heterotrophs • Photosynthetic autotrophs • Chemosynthetic autotrophs
Archaea • Methanogenic archaebacteria – inhabit anaerobic habitats and give off methane as a product of their metabolism. They live in the guts of cattle and are responsible for the intestinal gases that cattle produce. • Halophilic archaebacteria – live only in very salty conditions such as salt flats, where heat from the Sun has evaporated sea water. • Thermoacidophilic archaebacteria – live in hot acidic springs where temperatures may exceed 100oC and the pH may be as low as 2. Archaebacteria (archaios – ancient, bakterion – rod) live in extreme environments where few other organisms survive.They are believed to have been the first forms of life on Earth.
Eubacteria • Eubacteria (eu –good, true, bakterion – rod) make up the remaining bacteria. • They are found in all but the most extreme environments, in soils, sediments, floating free in air or water, in and on the other organisms. • They occur mainly as single cells but also group together in chains or clusters. We identify themby: • Investigating their growth requirements • Looking at their size and shape • Studying their reactions to specific stains (such as Gram stain)
Tosummarise: • What is meant by the five kingdom classification system? • What evidence is there that archaebacteria were the first forms of life on Earth? • What are themaindifferencesbetweenarchaebacteria and eubacteria?
