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52 Cards in this Set
- Front
- Back
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Compare and Contrast the overall cell structure of prokaryotes and eukaryotes |
Prokaryotes: (Bacteria, Archaea) - structurally simpler/smaller - DNA usually in a single, circularly arranged chromosome not in a membrane - do not have membrane enclosed organelles - cell walls: peptidoglycan for bacteria Eukaryotes: Plants, Animals, Fungi, Protozoa, Algae - DNA found in multiple chromosomes - DNA enclosed in a nucleus (histones and non histones) - have membrane enclosed organelles - cell walls (if present) are chemically simple - mitosis |
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Three Shapes of Bacteria |
1. Coccus (spherical) 2. Bacillus (rod shaped) 3. Spiral |
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Monomorphic bacteria |
maintain a single shape |
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Pleomorphic |
Many shapes (cornebacterium dipthirae) |
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Glycocalyx |
- (sugar coat) general term for substances that surround cells - bacterial glycocalyx is a viscous, gelatinous polymer external to the cell wall composed of polysaccharride, polypeptide or both - usually made inside the cell and secreted out - if glycocalyx firmly attaches to cell wall then it is a capsule - may protect bacteria from phagocytes - glycocalyx that helps cells in a bio film attach to each other and its target |
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Extracellular Polymeric Substance (EPS) - dont focus on this one, not on study guide |
glycocalyx that helps cells in a biofilm attach to each other and its target |
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Flagella |
- long filamentous appendages that propel bacteria (spins bacteria opposite of how the flagella spins) - too thing to see with light microscope, must be thickened with flagella stain or use electron microscope - connect onto the cell by hooking onto cell wall |
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Different Flagella Arrangements |
Atrichous - no flagella Petrichous - all around Polar Monotrichous - one flagella at one end Lophotrichous - many flagella at one end Amphitrichous - flagella on both polar ends |
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Axial Filaments (or endoflagella) |
bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell - corkscrew motion, only in sprochetes |
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Pili |
1. larger than fimbrae, only 1 or 2 per cell 2. motility and DNA transfer - twitching motility, grappling hook model - gliding motility, retraction Conjugation (sex) Pili - two cells hook up and transfer DNA in order to increase antibiotic resistance or digest easier, etc. |
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Bacterial Cell Wall |
1. complex, semi-rigid 2. prevents rupturing from water pressure 3. maintains shape 4. *point of anchorage for flagella 5. peptidoglycan |
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Gram Negative Cell Wall
1. thin inner layer of peptidoglycan 2. thicker outer membrane of protein and fat (look like a plasma/phospholipid bilayer) - only gram - can produce endotoxins due to lipopolysaccharides |
- consists of one or very few layers of peptidoglycan - periplasm: region between plasma membrane and outer membrane - more susceptible to mechanical damage - Outer membrane: Lipopolysaccharides, lipoproteins, and phospholipids - Evades phagocytosis - barrier to detergents, heavy metals, bile salts, dyes, enzymes |
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Gram Positive Cell Wall |
- cell wall consists of MANY layers of peptidoglycan - teicoic acids (alcohol + phosphate) - regulate flow of cations in/out cell - promotes growth - allow it to be antigenic specificity |
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Mycoplasm Cell Wall |
1. smallest known bacteria that can grow/reproduce outside living host cells 2. NO CELL WALLS, pass through bacteria filters, mistakened as viruses at first 3. plasma membrane has sterols - helps them from rupturing |
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Archaea |
- No cell walls or unusual walls made of polysaccharides/proteins but not peptidoglycan - have pseudomurein in cell walls instead - appear Gram negative due to lack of cell wall |
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Acid-Fast Cell Walls |
- contain high concentrations (60%) of a hydrophobic waxy lipid (mycolic acid) which prevents uptake of dyes - cell walls soluble to red color of carbol fuchism |
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Prokaryotic Plasma Membrane: - regulates what goes in/out of cell, also called cell membrane - ultra-thin layer of fat and protein |
- (inner membrane) is a thin structure lying inside the cell wall and enclosing the cytoplasm of the cell - phospholipids, lack sterols which makes them less rigid than eurkaryotic membranes - Phospholipid Bilayer contains: Peripheral, Intergral, Transmembrane, Glycoproteins, Glycolipids, Fluid Mosaic Model |
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Simple Diffusion |
net movement of molecules or ions from an area of high to low concentration to point of equilibrium - small molecules and fat-soluble molecules diffuse best |
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Facilitated Diffusion |
integral membrane proteins function as channels or carriers that facilitate the movement of ions or large molecules across a selectively permeable membrane - high to low concentration |
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Osmosis |
the net movement of water molecules across a selectively permeable membrane from an area of high to low concentration |
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Active Transport |
1. uses energy (ATP) to move stuff from low to high concentration 2. transport proteins required |
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Nucleoid |
- contains a single long, continuous and frequently circularly arranged thread of double stranded DNA called the bacterial chromosome - cells genetic info required for cell structures/functions - PLASMIDS - small, circular, double stranded DNA not connected to main bacterial chromosome, contain genetic info not crucial for survival but may be helpful such as antibiotic resistance |
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Ribosomes |
- site of protein synthesis. gives cytoplasm a granular appearance due to abundance of ribosomes - consists of: 1. protein 2. ribosomal RNA (rRNA) |
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Identify the functions of 4 inclusions |
bruh |
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Describe the functions of endospores, sporulation, and endospore germination |
bruh |
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Differentiate between prokaryotic and eukaryotic flagella movement |
Prokaryotic: flagella rotates Eukaryotic: flagella wavelike pattern ie. spermies |
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Define organelles and cytoplasm |
Organelles: structures with specific shapes and specialized functions and are characteristic of Eukaryotic cells ie. nucleus, endoplasmic reticulum, golgi, lysosomes, mitchondria, chloroplasts Cytoplasm: substance inside the plasma membrane and outside the nucleus, (water, protein and other chemicals) - forms a colloidal system 1. sol state - raw egg white 2. gel state - cooked egg white |
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Evidence of Endosymbiotic Theory of Eukaryotic Evolution |
Origin of eukaryotes from prokaryotes by Lynn Morgulis. Larger bacteria lost their cell walls and engulfed smaller bacterial cells. One organism lives inside another. 1. Ancestral Eukaryote formed a rudimentary nucleus when the plasma membrane folded around the chromosome - host provides nutrients while the smaller bacteria produced energy Ex. Chloroplasts may be descendants of photosynthesizing prokaryotes ingested by this nucleo plasm (big bacteria) Mitochondria and chloroplasts both have DNA that allows them to reproduce independently of their host cell Mitochondria and chloroplasts are similar in bacteria in size, shape, and protein synthesis, The same antibiotics that inhibit protein synthesis on ribosomes in bacteria also inhibit protein synthesis in mitochondria and chloroplasts. |
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Bacterial capsule |
- function: protection of cell from dying, chemicals, host body defenses; attachment to host cells - increases virulence in pathogenic species -chemical nature: polysaccharide (starch like material) - to view: use special capsule stains where capsule displaces stain to appear as a halo around the cell |
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Biofilms |
- slimy layers of bacteria that form organized, coordinated, and functional communities - quorum sensing -form on teeth, contact lenses, IUDs, lungs, ear infections, other infections, shower door scum etc. - protect bacteria from drugs and body defenses - estimated that 99% of bacteria in nature exist in biofilms |
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Fimbriae |
short, finger-like projections for attachment - important for virulence (attach to host cells) - not cilia for bacteria! |
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Why should we know gram + and gram - ? |
1. One of the important characteristics for identifying bacteria 2. choosing the best control method ie. penicillin, prevents construction of petidoglycan layer ie. lysozyme attacks peptidoglycan, causing cell wall to break down ie. lipopolysaccharide layer plays a protective role (in gram - bacteria) |
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Inclusion bodies |
- store nutrients (starch, glycogen, fats) for later use during periods of starvation - could store iron oxide or phosphate depending on cell |
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Endospore |
- survival form of bacteria produced within the cell in response to adverse environmental conditions - Central, terminal, sub terminal spores ie. Bacillus sp. and Clostridium spp. |
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Endospore |
spores can survive: 1. boiling 2. freezing 3. drying 4. vacuum 5. many disinfectants 6. time |
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Killing Spores |
1. steam autoclave 2. gas autoclave 3. some disinfectants 4. powerful radiation |
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Sporogenesis |
spore formation |
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Germination |
reactivation |
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Vegetative cells |
not spores |
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Fungus-like (filamentous) bacteria |
gram positive bacilli that form branching filaments, may form fungus like spores 1. common in soil |
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Antibiotics |
- substances produced by microbes that in small amounts inhibits another microbe (not all antibacterial drugs are antibiotics) - more than half of our antibiotics are produced by a Streptomyces spp. |
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Actinomyces |
- branching filaments and spore-case (sporangium) - cause actinomycosis (lumpy jaw) large abscess in jaw, fungal-like bacterial disease |
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Acid-fast bacteria |
- gram positive bacilli with wax coat on cell wall which increase survival in environment 1. Mycobacterium tuberculosis - tuberculosis 2. M. leprae - leprosy 3. Nocardia - abscesses linked to death in Aids |
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Mycoplasmas (fungus envy) |
- smallest known cells (submicroscopic) - never have cell walls - don't rupture because of small size and tough cell membrane - myco: filamentous - plasma: fluid - pleomorphic - variable in shape, look like fried egg colonies |
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Chlamydias (Gram - and oval shaped) |
- submicroscopic, have cell walls - Obligately intracellular parasites, will only grow inside of living host cells - energy parasites - no energy releasing metabolism - Cause: genital chlamydia, pneumonia |
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2 Forms of Chlamydia Cells |
1. Elementary Body - 0.3 um - rigid cell wall - can survive outside of host cells - infectious 2. Reticulate Body - 0.5 to 1.0 um - fragile cell wall - can't survive outside of host cells - not infectious - adapted for growth |
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Rickettsias |
- tiny oval to rod-shaped bacteria; just visible with light microscope - obligate intracellular parasites - but now widely separated from the chlamydia - most have arthropod vectors - genera: Rickettsia and Ehrlichia - Cause: 1. Rocky Mountain spotted fever 2. Typhus fevers (various vectors) |
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Inclusions |
reserve deposits found in prokaytotic and eukaryotic cells. Among the inclusions found in bacteria are: 1. metachromatic 2. polsaccharide 3. lipid 4. sulfur granules 5. carboxysomes 6. magnetosomes 7. gas vacuoles |
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Sulfur granules |
energy reserve |
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Carboxysomes |
contain Carbon Dioxide fixating enzymes |
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Manetosomes |
protect cell from hydrogen peroxide accumulation |
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Gas Vacuoles |
buoyancy |
