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44 Cards in this Set
- Front
- Back
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What is the smallest unit of life? |
Cells |
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What are the properties of living things |
growth and development reproduction and heredity metabolism movement and irritability cell support, protection and storage mechanisms transport in and out of cells |
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Where are prokaryotic cells found |
Eubacteria Archae |
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Properties of prokaryotic cells |
no nucleus or other organelles most have cell walls (except a few like mycoplasm) Simple but can engage in nearly every activity that eukaryotic cells can existance started 3.5BYA |
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Essential Structures of Prokaryoptic Cells |
Cell wall (some surface coating called glycocalix) Membrane Cytoplasm Robosomes Chromosomes (DNA) |
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Specific Structures found insome but not all |
Flagella Pili Fimbriae Capsules/slime layer inclusions actin cytoskeleton endospores |
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external structures of prokaryotes |
Appendages (cell extension) for motility -Flagella -axial filaments Attachment or Channel function -Fimbriae -Pili |
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Properties of appendages |
Protein (flaggelin) Diameter of flagella around 20 nm Length of Flagella 1-70 um flagella are inserted into curve and tubular hook Hook rotates 360 All spirila, half of Bacilli and some cocci are flagellated |
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Arrangement of Flagella |
Polar (attached at one or both ends) -monotrichous -lophotrichous -amphitrichous Non-polar arrangement -Peritrichous (attached randomly around cell) |
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Aquaspirillum |
Has amphi and lophotrichous flagellar arrangement |
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Thiospirillum |
Polar flagellated and zips at 5.2mm/min |
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Psuedomonas aeruginosa |
zips at 4.4mm/min |
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Escherichia coli |
zips at 1mm/min |
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Axial filaments (periplasmic flagella) |
Internal flagells enclosed in the space between the cell wall and the cell membrane found in spirochetes movement is by twisting or flexing motion |
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Define chemotaxis |
Bacteria movement in response to chemicals -towards nutrient or away from toxic/repellant co pound -cell membrane has receptors that bind specifically with other molecules |
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Define pilus |
long and thing tubular appendages made of tubular protein(pilin) essential in conjugation |
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What is conjugation |
Partial tranfer of DNA -provides genetic variation for bacteria -antibiotic resistance genes can be passed on -Conjugation in gram+ bacteria occurs but involves aggregation proteins rather than pilli |
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Define Fimbriae |
Bristle-like fibers emerging from the surface of many bacterial cells |
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Properties of fimbriae |
most contain protein short and numerous responsible for attachment and mutual clinging of cells Neisseria and E.Coli are not infectious when they lack fimbriae |
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What is the cell enevelope? |
complex of layers external to the cell protoplasm -cell membrane -cell wall -glycocalix The cell wall and membrane act as a single unit to mainting cell integrity |
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What is the glycocalix? |
The surface coating of macromolecules to protect the cell -vary in thickness, organization and chemical composition -responsible for persistent colonization of plastic catheters, intrauterine devices and metal pacemakers |
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Types of Glycocalices |
Slime layer Capsule |
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What is the slime layer |
Protects against dehydration and loss of nutrients -loose structure, easy to remove or wash off |
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What is the capsule of the cell? |
Thick and gummy layer diffucult to remove -combination of polysaccarides and protein -protection against phagocytes providing greater pathogenecity |
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What is the cell wall made of? |
Peptidogylcan (complex of sugars or glycans and amino acids) |
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Glycans in the cell wall |
N-acetyl glucosamine (G) N-acetyl muramic acid (M) |
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What is a bacterial species? |
Loosely defined as a collection of bacterial cells that shares an overall similar pattern or traits different from other groups of bacteria |
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What are strains and types? |
Variant forms within a species (subspecies) |
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How does one identify a bacterial species? |
Cell morphology Staining characteristics Special structues in cell macroscopic appearance biochemical reactions nucleotide composition of both DNA and RNA phylogenetic relationships and phenotypic characteristics |
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Identification and classification |
Micro and macroscopic morphology Physiological/biochemical characteristics chemical and serological analysis genetics and molecular analysis G+C base composition DNA analysis using genetic probes Nucleic acid sequencing and rRNA analysis |
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Medical ID of pathogens |
Gram stain morphology biochemical reactions metabolic requirements |
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What is an important taxonomic system |
Bergeys Manual of Determinitive Bacteriology (5 volumes) |
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What are the five volumes in BMDB? |
1. Domain Archaea and Bacteria 2.Proteobacteria 3.Low G+C gram-positive bacteria 4.High G+C gram-positive bacteria 5.Gram-negative cell walls |
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FIRMICUTES |
Bacteria with gram positive cell wall |
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GRACILCUTES |
Bacteria with gram-neg cell walls |
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TENERICUTES |
Bacteria with no cell walls |
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MENDOSICUTES |
bacteria with unusual cell walls (archaea) |
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Rickettsias |
Gram neg smallest bacteria atypical life style cannot survive and multiply outside host no metabolism of their own intracellular parasites transmitted by ticks, lice, fleas rocky mountain, spotted fever, typhus, Q-fever |
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Chlamydias |
Gram neg intracellular parasites require host for growth and metabolism not transmitted by arthropods thought before to be viruses trachoma (eye infection), chlamydiosis, parrot fever |
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Mycoplasms |
no cell wall very small plant, soil, animals Mycoplasma pneumonia |
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Photosynthetic bacteria |
autotrophs light trapping pigments energy from sunlight |
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Cyanobacteria:blue-green bacteria |
gram neg found in fresh and sea water contain thylakoids (internal membranes w/chlorophyll a and other pigments) Gas inclusion for floating physocyanin pigment (bluish-green), yellow or orange deplete oxygen from ponds pollutant-resistant found in hot springs, polar near hairs break rocks together with fungi |
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Green and purple sulfure bacteria |
photosynthetic bacteriochlorophyll live in sulfure springs, deep in lakes, swamps (fresh water) Brown, pink, purple, blue, orange color Use H2 or S for metabolism some deposit intracellular granules of sulfates |
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Archaea |
Unusal biochemistry and genetics no peptidoglycan in cell wall but branches hydrocarbons Not affected by antibiotics DNA with introns and histones 70S but structure is similar to 80S ribosomes of Eukarya |
