Bacteria Revision PDF
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Uploaded by WiseTropicalIsland4758
London South Bank University
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Summary
This document provides information on bacteria, including their features, shapes, environmental requirements, and types. It also discusses gram staining and explains different bacterial requirements for survival and growth. The text is accompanied by figures and diagrams which may be useful in understanding the biological concept better.
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Bacteria mmmmres of bacteria staininggram : Small...
Bacteria mmmmres of bacteria staininggram : Small celled positive and gram negative batraise · , single microorganisms. prokaryotic irregular placed single circular DNA chromosome : ,. Gram positive Thick peptidogly can = cell wall retains , crystal No membrane bound organelles. violet stain. (Streptococcus mutans ) Basic functions ; procreate/reproduce) , metabolise. Gram negative = Thin peptidogly can layer with thick lipopolysaccharide layer , doesn't retain crystal violet, appearing pink (porphyromonas gingivalis) (Endotoxins). · Mizearrangement tor periodontal disease + cares a mmmonmental ~ requirements : moisture : required for metabolic processes. most thrive in moist environments , though some can survive in · dry conditions by forming spores. Oxygen a) Anaerobes : - do not need oxygen may , even harm it. settle at bottom where oxygen is lowest. · (Porphyromonas gingivalis). b Aerobes - require oxygen for survival found near surface where oxygen is highest. , ) microderophiles - grow optimally in lower oxygen environments but still requires some 6) facultative anaerobes > adapts and lives within range of different oxygen levels. (Streptococcus mutans) - carbon dioxide capnophiles need increased co2 to grow but most can grow with normal atmospheric co2 levels. : · , Temperature : 1. Psychrophiles - cold , Optimum 5-15 %.. 2 mesophiles - moderate , optimum 30-40 %.. Thermophiles 3 high optimum 60-70 % - , 4. Hyperthermophiles extremely high 90-1000. -> , PH : 1. Acidophiles z. neutrophils 3. Alkaliphiles Light : · High intensity visible light can kill bacteria , low power visible and near infrared can promote bacterial growth. Osmotic effect : 1. Halophiles -> grow and develop in high salt concentration areas. mechanical stress : Some can withstand pressure/agitation by forming biofilms or protective structures (spores/capsules)· Classification of organisms g of bacteria · : Kingdom Procaryote Systematic classification of organisms into groups called TAXONOMY. Division Firmicutes name classically comes from last 2 ranks ; Genus and species. Subdivision Low DNA content species doesNot begin with Capital , name usually in italics. Family Streptococcaceae (e g. S salivarius.. Genus Streptococcus Species Streptococcus salivarius mmmmria With dentistry ass : · Periodontal disease : · Porphyrinomonas gingivalis (gram- anaerobic inflammation tissue destruction) , , + Aggregatibacter actinomycemcomitans (gram- facultative localised aggressive periodontitis ) · , ,. Temponema denticola (spirochete anaerobic invades and damages aggressive form). , , , caries : Streptococcus mutans (gramt facultative digests sugar to produce. , , acide stores polysaccharides , continue producing acid) Lactobacilli. (gramt facultative micro-aerophiles or acid producing thrive in sugar presence ) · , , ,.
