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101 Cards in this Set
- Front
- Back
What is a microorganism?
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An organism too small to be seen without a microscope
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What are the 3 domains of the current system of classification?
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Bacteria, Archaea, Eukarya
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What are the 4 kingdoms of eukaryotes?
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Protista, Fungi, Animalia, Plantae
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What are the general, distinguishing characteristics of bacteria?
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- prokaryotes
-peptidogylcan cell wall - unicellular and lack nuclei - reproduce asexually - much smaller than eukaryotes - found everywhere there is sufficient moisture |
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What are the general, distinguishing characteristics of archaea?
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- prokaryotes
- pseudopeptidoglycan cell wall - unicellular and lack nuclei - reproduce asexually - much smaller than eukaryotes - many live in extreme environments |
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Three types of archaea that live in extreme environments
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Methanogens (decomposers, methane)
Halophiles (salt loving) Thermophiles (heat loving) |
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General characteristics of algae
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Eukaryote
Kingdom Protista Photosynthetic Unicellular or multicellular Reproduce asexually OR sexually Most are sessile Categorized by storage products, pigmentation, cell wall composition |
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General characteristics of protozoans
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Eukaryote
Kingdom Protista Unicellular Heterotrophic Free-living in water, or parasitic in host Reproduce asexually or sexually Most are motile |
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Sessile
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Fixed in one place, immobile
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Motile
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Able to move spontaneously and actively
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General characteristics of fungi
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Eukaryote
Kingdom Fungi Unicellular or multicellular heterotrophic detrivores Reproduce asexually OR sexually Cell walls made of chitin |
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2 types of fungi
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Molds
yeasts |
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heterotrophic detritivores
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obtain nutrients by consuming detritus (decomposing organic matter)
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Characteristics of molds
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type of fungi
multicellular grow hyphae reproduce by spores |
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Characteristics of yeasts
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type of fungi
unicellular reproduce by budding some produce spores |
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General characteristics of viruses
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Acellular
Obligate parasites Host and/or tissue specific basic types have a protein coat and nucleic acid, no membrane - Can't be seen w/o electron microscope |
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Robert Hooke
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early observations 1665
coined the term "cell" observed dead cork cells in plants |
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Antoni von Leeuwenhoek
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1673 - 1723
lensmaker, created first microscope (primitive), discovered "animalcules / beasties" in plaque and pond water |
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Francesco Redi
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1626 - 1697
Did experiments to investigate spontaneous generation (meat in open jar, corked jar, and jar covered with gauze) |
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Louis Pasteur
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1861 - swan neck flask experiments disproved spontaneous generation (abiogenesis)
- germ theory of disease - fermentation - discovered facultative anaerobes - introduced industrial microbiology |
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Robert Koch
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- 1843 - 1910
- Koch's Postulates 1. causative agent must be found in all cases of the disease and absent in healthy hosts 2. agent must be isolated and grown outside the host 3. when agent is introduced in healthy host, the host must get the disease 4. Same agent must be re-isolated from the diseased experimental host |
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Hans Christian Gram
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- 1884
- Gram stain - Differentiation of bacteria based on staining procedures - Two types of bacteria (Gram positive or Gram negative) - Allowed Koch's 1st postulate to be tested |
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Ignaz Semmelweis
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- 1818 - 1865
- Suggested physicians wash hands before examining patients - reduced maternal death rate from puerperal fever from 12 % to 1 % - Father of Aseptic Technique |
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Joseph Lister
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- 1827 - 1912
- Recognized Semmelweis's work - Lister's Antiseptic Technique 1. spray wounds and incisions with carbolic acid 2. soak surgical instruments and dressings |
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Florence Nightingale
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1820 - 1910
- observed that death rates were higher in hospitals than battlefields during Crimean War - Called for fresh water, improved hygiene, fresh food - established Nightingale School of Nursing |
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John Snow
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1823 - 1854
- pioneer of epidemiology - mapped London cholera outbreak in 1854, isolated source to the local water pump - advised officials to remove handle of pump - when done, this contained the epidemic |
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Edward Jenner
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1749 - 1823
- Pioneer of immunology - Observed that milk maids who had cow pox were immune to small pox - injected boy with cow pox, then small pox ... boy was immune - Vaccinations (vacca is Latin for cow) |
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Paul Ehrlich
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- 1854 - 1915
- pioneer of chemotherapy - hunted for the magic bullet (harmful to microbes, not the host) - identified Salvarsen (salvation using arsenic), effective against syphilis |
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What are the steps of the scientific method?
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- observations
- questions - hypothesis - experimentation - accept, reject, or modify hypothesis |
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Some achievements of the modern age of microbiology
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- understanding of the shared biochemistry of all life (the transfer of e- and H+)
- identification of the domain archaea using molecular techniques - use of genetic engineering to produce drugs in microbes (insuline, hGH) - discovery of new species of microbes through genetic prospecting - understanding that bacteria are essential to the environment (nitrogen fixation, decomposition, mutualism) |
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Why is understanding cell structure and function important to humans?
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understanding cells allows us to:
- understand how microbes cause disease - understand how microbes defend themselves - develop treatments to inhibit or kill microbes - not harm our own cells in the process |
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basic characteristics of living organisms
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- cells (cell theory)
- growth and development - reproduction - responsiveness - metabolism - evolution and adaptation to environment |
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glycocalyx of bacteria
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slime layer and capsule
gelatinous sticky substance composed of polysaccharides, polypeptides, or both. Protects cells from dessication. prevents drying out/dehydration |
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pathogen with glycocalyx
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streptococcus pneumoniae
pneumococcal pneumonia pathogenesis due to capsule |
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flagella of prokaryotes
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composed of proteins
differences in proteins identify serovars (in blood - serum) allow motility and taxis |
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taxis
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movement toward or away, in one direction
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flagella arrangements
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monotrichous
lophotrichous amphitrichous peritrichous |
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runs and tumbles
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reg. flagella:
runs result from counterclockwise rotation, tumbles result from clockwise rotation runs in one direction, but can tumble when something is detected that would cause harm |
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characteristics of flagella
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rotate 360 degrees at over 100,000 rpm
can change from counter clockwise to clockwise runs punctuated by tumbles multiple flagella always rotate in unison receptors signal flagella to adjust speed and direction of rotation |
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pathogen with flagella
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Helicobacter pylori (lophotrichous flagella)
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endoflagella (axial filament)
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endoflagella form axial filaments, allow spirochete motility
(spirochete corkscrews and moves forward) |
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pathogen with endoflagella
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Borrelia burgdorferi
(Lyme's disease) the spiraling movement of bacteria facilitates penetration of host tissues. |
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fimbriae
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attachment in Gram negative cells
shorter than flagella hundreds per cell can act as "grappling hooks" important in formation of biofilms |
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pathogen with fimbriae
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Neisseria gonorrhea
fimbriae attachment to epithelial cells of reproductive tract |
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pili
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- conjugation and genetic exchange
longer than fimbriae shorter than flagella allow exchange of genetic information |
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internal structures of prokaryotic cells
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plasmids, endospores, inclusions, nucleoid region, ribosome, cytosol, cytoskeleton
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plasmids
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extra chromosomal DNA, special genes
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endospores
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- the main chromosome of bacterial cells
- thick protective coat - protected copy of bacterial chromosome - resistant to drying, heat, radiation, chemicals |
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inclusions
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reserve deposits of lipids, starch, nitrogen compounds, sulfur
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nucleoid region
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not a nucleus, circular, naked, single chromosome
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ribosome
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two subunits - 50S and 30S = 70S (sedimentative, not a direct correlation)
Proteins and RNA |
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cytoskeleton
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protein filaments
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what is the shape of a bacterial cell determined by?
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cell wall
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what are the arrangements of bacterial cells?
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chains
packets clusters |
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what are the basic shapes of prokaryotic cells?
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coccus, bacillus, spirillum
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describe bacterial cell wall composition
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they have a carbohydrate backbone of alternating peptidoglycan sugars (NAG - N-acetylgucosamine) and (NAM - N-acetylmuramic acid), connected vertically by tetrapeptide crossbridges and horizontally by connecting chains of amino acids.
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chains
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cells divide in one plane (streptococcus spp)
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packets
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cell divides in two or more planes perpendicular to each other (Sarcina spp)
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clusters
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cell divides in several planes at random (Staphyloccus spp)
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teichoic acid
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unique polyalcohol found in Gram positive cell walls. Can be covalently linked to lipids, forming lipoteichoic acid.
Have a negative charge, give the surface of Gram-positive cells a negative charge and affect ion passage. |
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lipopolysaccharide
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The outer leaflet of Gram-negative cell walls. The lipid portion is known as Lipid A.
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lipid A
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The lipid portion of LPS. It is released from the LPS when the cell dies.
can cause shock, blood clotting, and fever in humans |
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porin
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proteins that cross a cellular membrane and act as a pore through which molecules can diffuse.
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periplasmic space
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space that contains periplasm, it is between the outer membrane and the cell membrane of Gram-negative organisms.
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group translocation
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type of active transport, occurs in some prokaryotes
the substance being carried across the cell membrane is chemically changed during transport. Very efficient at bringing substances into a cell |
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why are Gram-negative cells more pathogenic than Gram-positive
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the outer membrane may prevent the movement of penicillin to the underlying peptidoglycan
killing a cell causes it to release lipid A, which makes people more sick. |
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what are the differences between Gram positive and Gram negative cell walls?
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The G-+ cell wall has a thick layer of peptidoglycan and teichoic acids that anchor the wall to the cell membrane.
The G - cell wall has a thin layer of peptidoglycan and an outer membrane composed of LPS, phospholipids, and proteins. |
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simple diffusion
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movement of a chemical down a concentration gradient, from high concentration to lower. Requires no energy output from the cell.
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facilitated diffusion
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movement of substances across a cell membrane through channel proteins.
no energy required from the cell, it is provided by electrochemical gradient |
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active transport
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the movement of a substance against its electrochemical gradient via carrier proteins.
Requires ATP |
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uniport system
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one substance transported at a time
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antiport
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simultaneously transport 2 chemicals, but in opposite directions ... one in, one out
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cotransport
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uniport and symport,
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isotonic
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solutions on either side of a selectively permeable membrane have the same concentration of solutes.
neither side of a selectively permeable membrane will experience a net movement of water |
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hypertonic
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concentrations of solutes are unequal, the solution with the higher concentration is hypertonic
cells in hypertonic solutions shrink due to the net movement of water out of the cell. |
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hypotonic
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the solution with lower concentration of solutes is hypotonic in comparison
cells in hypotonic solutions undergo a net gain of water. animal cells burst, in plants (cells with a wall) the pressure of the water pushing against the interior movement of the wall eventually stops the movement of water into the cell. |
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Streptococcus pneumonia
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cellular structure - GLYCOCALYX contributes to pathogenesis
pneumonia |
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Heliobacter pylori
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pathogenesis due to strong
LOPHOTRICHOUS flagella stomach ulcers, stomach cancer |
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Borrelia burgdorferi
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pathogenesis due to spiraling movement of endoflagella
Lyme disease |
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Neisseria gonorrhea
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pathogenesis from fimbriae attachement to epithelial cells of reproductive tract
Gonorrhea, PID, epidymitis |
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what are the energy sources used for light microscopy
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the energy of electrons, electrons are shot at the image
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magnification
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the apparent increase in the size of an object that results from the bending or refraction of light as it passes through a lens
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empty magnification
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lacks clarity
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why does a blue filter enhance resolution?
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blue light provides shorter wave length ratiation
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resolution
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the ability to distinguish between objects that are close together
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difference between a simple microscope and a compound microscope
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a simple microscope contains a single magnifying lens
compound light microscopes have more than one magnifying lens (ocular and objective), uses visible light passing through a specimen (light source and blue filter). |
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contrast
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differences in intensity between two objects
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condenser
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focuses light through specimen
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diaphragm
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controls the amount of light entering the condenser
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coarse focusing knob
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moves stage up and down to focus the image
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body
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transmits the image from the objective lens to the ocular lens using prisms
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ocular lens
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remagnifies the image formed by the objective lens
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how is total magnification calculated
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ocular magnification x objective magnification
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what is a simple stain?
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composed of a single basic dye, ex: crystal violet
types of info: size, shape, arrangement of cells |
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differential stain
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more than one dye is used (Gram stain, acid fast stain, endospore stain), allows for different cells, chemicals or structures to be examined
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types of organisms identified by an acid fast stain
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stains cells of the genera mycobacterium and nocardia. These types of cells have a waxy lipid in their cell walls that doesn't work well with the Gram stain.
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special stain
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special stains are simple stains designed to reveal special microbial structures (ex: negative stains, flagellar stains, fluorescent stains)
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why is Carl Woese important in the field of taxonomy?
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compared rRNA subunits in cells
proposed a new classification system to reflect differences: eukarya, bacteria, archaea |
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phage typing
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method of classifying microorganisms in which unknown bacteria are identified by observing plaques
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serology
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the study and use of immunological tests to diagnose and treat disease or identify antibodies or antigens
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how is a dichotomous key used?
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stepwise between paired characteristics to assist in identifying microbes
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