Microbes Study Guide word

Microbes Study Guide word - Microbes Study Guide...

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Microbes Study Guide Prokaryotes -divided into bacteria and archaea. They lack cell nucleus, lack membrane -bound organelles, one chromosomes, don't do mitosis, have nucleoids, no cytoskeleton, higher metabolic rate, shorter generation time, unicellular, circular DNA, cell division by binary fission (clones), asexual reproduction, cell wall, cytoplasm Eukaryotes -have a nucleus, membrane bound organelles (golgi apparatus, mitochondria), cytoskeleton, cell division by mitosis or meiosis, cell wall, linear DNA, monophyletic group Archaea- survive in extreme conditions (extremophiles), not pathogens, halobacteria (use sunlight as a source and other species of archaea to fix carbon), mathanogens, fix nitrogen, ether-linked membrane lipids Bacteria -peptidoglycan cell wall, plasmids, ester-linked membrane lipids, some conduct chlorophyll-based photosynthesis, fix nitrogen Why are microbes problematic for phylogeny reconstruction? o Some traits are not clear if they are homologous Morphology for example o Many taxa are unculturable o Other traits are of limited utility Nucleus (present/absent) Does not resolve relationships within groups o Universal homologies Do not meet requirements for phylogenetically informative traits Examples of universal homologies Molecular and cellular features Use of DNA as a genetic material (everything has DNA hence the hypothesis that all living organisms share a common ancestry) Three letter genetic code Central dogma (DNA-> RNA ->protein) Specific complexes and genes Ribosomal proteins and RNA RNA polymerase proteins rRNA -all cellular organisms have ribosomes o All have homologous subunits of the ribosomes including specific ribosomal proteins and ribosomal RNAs (universally homologous genes) o rRNA sequences are highly similar but have some variation between species o Each position in the rRNA sequence can be considered a distinct character trait (multiple character states) Alignment -method of assigning homology to individual stretches of nucleotides in different sequences o Allows one to have multiple traits within individual genes o Each column in alignment = a different character Vertical transmission- reproduction where genes are passed from one generation of species to the next generation of species, binary fission
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Lateral Gene Transfer- process in which an organism incorporates genetic material from
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Microbes Study Guide word - Microbes Study Guide...

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