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Answer 3 marks 22 1 3 citrate utilisation describe

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Answer:3 marks22
1.3.Citrate utilisation: describe theEnterococcus faecalisandEnterobacteraerogenesgrowth results and explain what they mean.Answer:2 marks4. Define each of the following (0.5 mark/definition). Each definition should bearound 25 words or less.1.Thermophile, mesophile, psychrophile, piezophile, halophile2.Aerobe, anaerobe, facultative anaerobeAnswer:4 marks totalPart 4 Gram stainingWork in pairsBacteria are defined by their prokaryotic cell type.Bacterial morphology is oftenconsidered to be dominated by a few simple shapes - rods, spheres or spirals.However, there is considerable morphological diversity in the bacterial world.Largely because of difficulties in determining phylogenetic relationships, it isconvenient to group the bacteria into rather loosely defined 'form groups'.Examples of 'form groups' include appendaged bacteria, sheathed bacteria,gliding bacteria (all based on a particular morphological feature), cyanobacteria(defined by a particular type of photosynthesis), or groups based on shape andcell wall type (e.g. Gram-positive cocci) and so on.At present attempts are beingmade to construct a phylogenetic taxonomy based on similarities in nucleic acid23
sequences as a measure of relatedness, and such studies are beginning to showhow unrelated some of the organisms in certain 'form groups' are (in particularhow unsatisfactory morphology is as an indication of relatedness), but for themoment we retain these 'form groups'.These sessions are intended to show a few morphological types from these 'formgroups' as an introduction to diversity in the bacterial world.Most prokaryoticcells are considerably smaller than eukaryotic cells, but there are exceptions,particularly amongst the cyanobacteria. Unfortunately some of the more exotictypes of bacteria are very difficult to handle in culture, so we are restricted in therange of bacteria shown.The Gram stainSome staining procedures give different reactions with different bacteria and socan be helpful for identification purposes.The most significant differential stainingreaction in microbiology is the Gram stain. The Gram reaction correlates well withcellular characteristics related to cell wall composition. Gram-positive cells retainthe primary stain crystal violet and appear blue/purple, whereas Gram-negativecells leak the primary stain in the presence of alcohol or acetone and stain onlywith the counterstain, usually safranin or neutral red. The Gram reaction is ofprime importance in the description of an unknown bacterium and its subsequentallocation to a particular group of organisms.Gram staining procedure1. Degrease a microscope slide by passing it briefly through a Bunsen flame whileholding it with forceps.Label slide with diamond pen.

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Term
Spring
Professor
N/A
Tags
Bacteria, P putida

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