Test 1 – Microbiology Answers – Flashcards
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| microbes or microoraganisms |
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| are minute living things that individually are usuallly too small to be seen with the unaided eye |
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| genus |
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| the two names that scientific nomenclature assigns each organism |
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| specific epithet |
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| follows the genus and is not capitalized |
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| bacteria |
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| are relatively simple, single-celled organisms, their genetic material is not enclosed by a nuclear membrane; therefor they are called prokaryotes |
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| prokaryotes |
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| meaning preneuclus; this included bateria and archaea |
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| archaea |
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| consists of prokaryothic cells, but if they have cell walls, the walls lack prpitdoglycan; usually found in extreem enviornemtns such as excess salt and heat |
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| eukaryotes |
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| organisms whose cells have a distinct nucleus containing the cells genetic material, surrounded by a special envelope called the nuclear membrane |
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| protozoa |
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| are unicellular eukaryotic microbes |
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| algae |
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| are photosynthetic eukaryotes with a wide variety of shapes and both sexual and asexual reproductive forms |
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| heleminths |
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| the two major groups of parasitic worms are the flatworms and the round worms |
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| cell theory |
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| the theory that all living things are composed of cells |
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| spontaneous generation |
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| some forms of life could arise spontaneously from nonliving matter |
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| biogenesis |
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| the claim that living thing cells can arise from only preexisiting cells |
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| eptic technologies |
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| techniques that prevent contamination by unwanted microbes |
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| fermentation |
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| paster found that instead of the air converting sugars into alchol it was actually a microorganism called yeast convert sugars to alchol in the absence of air |
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| pasteurization |
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| pasteur found a solution the the spoilage of many foods, the solution to the problem was to heat beer, wine, and cheese to kill off many of the bacterium |
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| germ theory of disease |
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| the realization that yeast plays a crutial role in fermentation, this showed the link between the activity of a microbe and physical and chemical changes in organic material |
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| Koch's postulates |
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| koch cultured a bacterium found in cows blood, thus established a sequence of experimental steps for directly relating a specific microbe to a specific disease |
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| immunity |
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| Jenner discovered that a milk maid was immune to small pox he isolated the blood in the cow and injected it into a 8 year old boly and thus he was immune to small pox |
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| chemotherapy |
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| treatment of a disease from use of chemicals |
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| antibiotics |
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| chemicals produced natrually by bacteria and fung to act against other microorganisms |
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| synthetic drugs |
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| drugs made within a labratory |
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| bacteriology |
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| the study of bacteria, started with van-Leeuwenhoek's first examination of tooth scrapings |
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| mycology |
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| the study of fungi |
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| parasitology |
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| the study of parasites |
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| genomics |
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| the study of all organisms genes |
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| immunology |
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| the study of immunity |
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| virology |
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| the study of viruses |
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| recombinant DNA |
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| Paul Berg showed that fragments of human or animal DNA (genes) that code for important proteins to attach to the bacterial DNA |
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| microbial genetics |
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| studies the mechanisms by which microorganisms inherit traits |
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| molecular biology |
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| specifically studies how genetic information is carried in molecules of DNA and how DNA directs the sythesis of protiens |
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| microbial ecology |
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| the study of the relationship between microorganisms and their enviornment, originated with the work of Beijerneck and Winorgradsky |
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| biotechnology |
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| commercial use of microorganisms to produce common foods and chemicals |
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| gene therapy |
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| insertikng a missing gene or repacing a defective one in human cells |
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| normal microbiota |
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| the normal microbes we are born with |
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| resistance |
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| the ability to ward off disease |
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| biofilm |
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| a complex aggregation of microbes |
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| infectious disease |
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| is a disease in which pathogens invade a susceptible host |
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| atom |
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| the smallest componet of a pure substance that exhibits physical and chemical properties of that substance |
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| molecules |
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| atoms interact with each other in certain combinations |
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| chemisrty |
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| the interaction between atoms and molecules |
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| ionic bonds |
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| is the attraction between ions of opposite charges that holds them together to forma stable molecule |
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| cations |
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| possitivly charged |
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| antions |
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| negitivly charged ion |
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| hydrogen bond |
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| a hydrogen atom that is covelently bonded to one oxygen or nitrogen attom is attracted to another oxygen or nitrogen atom |
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| mole |
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| the molecular weight expressed in grams |
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| chemical reactions |
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| the making or breaking of bonds between atoms |
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| chemical energy |
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| some change of energy occurs whenever bonds between atoms are formed or broken during chemical reactions |
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| endergonic reaction |
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| a reaction that absorbs energy |
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| exergonic reaction |
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| a reaction that gives off energy |
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| anabolism |
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| to elements combine to produce a product A+B --> AB |
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| catabolism or decomposition reaction |
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| when a molecule breaks down into two or more elements AB---> A+B |
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| exchange reactions |
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| when three or more elements recombine to form new products AB+CD ---> AD+BC |
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| reversiable reactions |
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| a chemical reaction that is readily reversable when the end product can revert back the the original molecule, usually indicated by two arrows |
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| Inorgaic Compounds |
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| typically lack carbon in which ionic bonds may play an important roll |
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| organic compounds |
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| always contain carbon and hydrogen and typically are structurally complex |
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| polar molecule |
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| any molecule that is not symetric and has an unequal distribution of charges (has two polls like a magnet) |
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| solvent |
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| a disolving medium usually water |
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| dissasociation |
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| seperation into individual molecules |
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| solute |
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| the substance being disloved like salt in water |
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| ionization |
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| or dissasociation, the breaking apart of molecules into ions |
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| light microscope |
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| any microscope that uses visible light to observe a speciem |
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| compound light microscope |
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| has a series of lenses and uses visible light as a source of its illimunation, the shorter wavelenghts makes the resolution better, immersion oil stops the light from refracting as much |
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| illuminator |
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| the light source |
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| condensor |
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| where the light form the illuminator passes through, which has lenses that direct the light rays through the specimen |
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| total magnification |
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| the oculars magnification (x10) x the objectives magnifications |
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| resolution |
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| the ablility of the lenses to distinguish fine detail and structure |
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| refractive index |
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| is a measure if the light bendin ablity of a medium |
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| brightfeild illumination |
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| the area around the specimen is light |
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| darkfeild microscope |
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| the area around your specimen is dark |
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| phase contrast microscope |
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| gives detailed examination if internal structures in living microorganisms, Accentuates diffraction of the light that passes through a specimen |
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| antibodies |
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| are natural defense molecules that are produced by humans and many animals in reaction to a foreign substance |
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| flurescence microscopy |
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| uses uv light, Fluorescent substances absorb UV light and emit visible light Cells may be stained with fluorescent dyes (fluorochromes) |
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| confocal microscopy |
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| Cells stained with fluorochrome dyes Short wavelength (blue) light used to excite the dyes The light illuminates each plane in a specimen to produce a three-dimensional image Up to 100 µm deep |
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| electron microscope |
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| Uses electrons instead of light The shorter wavelength of electrons gives greater resolution |
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| two-photon microscopy |
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| Cells stained with fluorochrome dyes Two photons of long- wavelength (red) light used to excite the dyes Used to study cells attached to a surface Up to 1 mm deep |
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| scanning acoustic microscopy (SAM) |
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| Measures sound waves that are reflected back from an object Used to study cells attached to a surface Resolution 1 µm |
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| transmission electron microscopy (TEM) |
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| Ultrathin sections of specimens Light passes through specimen, then an electromagnetic lens, to a screen or film Specimens may be stained with heavy metal salts |
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| scanning electron microscope |
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| An electron gun produces a beam of electrons that scans the surface of a whole specimen Secondary electrons emitted from the specimen produce the image |
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| scanned-prob microscopy |
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| Scanning tunneling microscopy (STM) uses a metal probe to scan a specimen Resolution 1/100 of an atom Atomic force microscopy (AFM) uses a metal- and-diamond probe inserted into the specimen. Produces three-dimensional images. |
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| staining |
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| Coloring the microbe with a dye that emphasizes certain structures |
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| smear |
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| A thin film of a solution of microbes on a slide A smear is usually fixed to attach the microbes to the slide and to kill the microbes |
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| basic dye |
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| the chromophore is a cation |
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| acidic dye |
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| the chromophore is an anion |
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| negitive staining |
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| Staining the background instead of the cell |
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| simple stain |
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| Use of a single basic dye |
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| mordant |
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| may be used to hold the stain or coat the specimen to enlarge it |
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| differential stains |
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| Used to distinguish between bacteria Gram stain Acid-fast stain |
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| gram stain |
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| Classifies bacteria into gram-positive or gram-negative Gram-positive bacteria tend to be killed by penicillin and detergents Gram-negative bacteria are more resistant to antibiotics |
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| acid-fast stain |
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| Stained waxy cell wall is not decolorized by acid- alcohol Mycobacterium Nocardia |
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| special stains |
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| Used to distinguish parts of cells Capsule stain Endospore stain Flagella stain |
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| endospore staining |
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| Primary stain: Malachite green, usually with heat Decolorize cells: Water Counterstain: Safranin |
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| flagella staining |
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| Mordant on flagella Carbolfuchsin simple stain |
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| carbon skeleton |
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| The chain of carbon atoms in an organic molecule |
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| functional groups |
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| responsible for most of the chemical properties of a particular organic compound. |
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| organic compounds |
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| Small organic molecules can combine into large macromolecules |
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| macromolecules |
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| polymers consisting of many small repeating molecules |
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| monomers |
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| smaller organic molecules |
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| polymers |
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| Monomers join by dehydration synthesis or condensation reactions |
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| carbohydrates |
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| Cell structures and energy sources Consist of C, H, and O with the formula (CH2O)n Monosaccharides are simple sugars with 3 to 7 carbon atoms |
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| disacharides |
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| are formed when 2 monosaccharides are joined in a dehydration synthesis Disaccharides can be broken down by hydrolysis |
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| Oligosaccharides |
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| consist of 2 to 20 monosaccharides |
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| Polysaccharides |
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| consist of tens or hundreds of monosaccharides joined through dehydration synthesis Starch, glycogen, dextran, and cellulose are polymers of glucose that are covalently bonded differently Chitin is a polymer of 2 sugars repeating many times |
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| lipids |
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| Primary components of cell membranes Consist of C, H, and O Are nonpolar and insoluble in water |
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| simple lipids |
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| Fats or triglycerides Contain glycerol and fatty acids; formed by dehydration synthesis |
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| Saturated fat |
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| No double bonds |
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| Unsaturated fat |
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| One or more double bonds in the fatty acids cis: H atoms on the same side of the double bond trans: H atoms on opposite sides of the double bond |
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| complex lipids |
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| Contain C, H, and O + P, N, or S Membranes are made of phospholipids |
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| steriods |
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| 4 carbon rings with an ?OH group attached to one ring Part of membranes |
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| proteins |
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| Are essential in cell structure and function Enzymes are proteins that speed chemical reactions Transporter proteins move chemicals across membranes Flagella are made of proteins Some bacterial toxins are proteins |
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| amino acids |
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| Proteins consist of subunits |
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| peptide bonds |
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| are between amino acids are formed by dehydration synthesis |
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| primary structure |
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| polypeptide chain |
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| secondary structure |
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| occurs when the amino acid chain folds and coils in a regular helix or pleats |
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| tertiary structure |
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| occurs when the helix folds irregularly, forming disulfide bonds, hydrogen bonds, and ionic bonds between amino acids in the chain |
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| quaternary stucture |
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| consists of 2 or more polypeptides. |
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| nucleotides |
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| Nucleotides consist of a Pentose Phosphate group Nitrogen-containing (purine or pyrimidine) base |
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| nucleosides |
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| consist of a Pentose Nitrogen-containing base |
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| DNA |
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| Deoxyribonucleic acid Has deoxyribose Exists as a double helix A hydrogen bonds with T C hydrogen bonds with G |
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| RNA |
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| Ribonucleic acid Has ribose Is single-stranded A hydrogen bonds with U C hydrogen bonds with G |
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| ATP |
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| Adenosine triphosphate Has ribose, adenine, and 3 phosphate groups. Is made by dehydration synthesis Is broken by hydrolysis to liberate useful energy for the cell... when water is added to ATP --> ADP |
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| Prokaryote |
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| pre neucleus One circular chromosome, not in a membrane No histones Average size: 0.2 ?1.0 µm ? 2 ? 8 µm Most bacteria are monomorphic A few are pleomorphic No organelles Peptidoglycan cell walls if Bacteria Pseudomurein cell walls if Archaea Binary fission |
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| Eukaryote |
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| true neucleus Paired chromosomes, in nuclear membrane Histones Organelles Polysaccharide cell walls Mitotic spindle |
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| Bacillus |
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| rod shaped |
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| Coccus |
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| spherical |
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| Spiral |
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| Spirillum Vibrio Spirochete |
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| Pairs |
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| Diplococci, diplobacilli |
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| Clusters |
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| Staphylococci |
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| Chains: |
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| Streptococci, streptobacilli |
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| Glycocalyx |
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| Outside cell wall Usually sticky Capsule: neatly organized Slime layer: unorganized and loose Extracellular polysaccharide allows cell to attach Capsules prevent phagocytosis |
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| Flagella |
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| Outside cell wall Made of chains of flagellin Attached to a protein hook Anchored to the wall and membrane by the basal body |
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| Motile Cells |
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| Rotate flagella to run or tumble Move toward or away from stimuli (taxis) Flagella proteins are H antigens (e.g., E. coli O157:H7) |
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| Axial Filaments |
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| Also called endoflagella In spirochetes Anchored at one end of a cell Rotation causes cell to move |
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| the cell wall |
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| Prevents osmotic lysis Made of peptidoglycan (in bacteria) |
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| Fimbriae and Pili |
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| Pili Facilitate transfer of DNA from one cell to another Gliding motility Twitching motility Fimbriae allow attachment |
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| Fimbriae and Pili |
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| Pili Facilitate transfer of DNA from one cell to another Gliding motility Twitching motility Fimbriae allow attachment |
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| Peptidoglycan |
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| Polymer of disaccharide: N-acetylglucosamine (NAG) N-acetylmuramic acid (NAM) |
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| Peptidoglycan in Gram-Positive Bacteria |
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| Linked by polypeptides |
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| gram possitive cell wall |
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| Thick peptidoglycan Teichoic acids 2-ring basal body Disrupted by lysozyme Penicillin sensitive |
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| gram negitive cell wall |
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| Thin peptidoglycan Outer membrane Periplasmic space 4-ring basal body Endotoxin Tetracycline sensitive |
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| gram negitive outter cell membrane |
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| Protection from phagocytes, complement, and antibiotics O polysaccharide antigen, e.g., E. coli O157:H7 Lipid A is an endotoxin Porins (proteins) form channels through membrane |
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| Gram stain mechanism |
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| Crystal violet-iodine crystals form in cell Gram-positive Alcohol dehydrates peptidoglycan CV-I crystals do not leave Gram-negative Alcohol dissolves outer membrane and leaves holes in peptidoglycan CV-I washes out |
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| atypical cell walls |
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| Acid-fast cell walls Like gram-positive Waxy lipid (mycolic acid) bound to peptidoglycan Mycobacterium Nocardia |
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| Mycoplasmas atypical cell walls |
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| Lack cell walls Sterols in plasma membrane |
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| Archaea atypical cell walls |
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| Wall-less or Walls of pseudomurein (lack NAM and D-amino acids) |
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| damage to the cell wall |
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| Lysozyme digests disaccharide in peptidoglycan Penicillin inhibits peptide bridges in peptidoglycan Protoplast is a wall-less gram-positive cell Spheroplast is a wall-less gram-negative cell Protoplasts and spheroplasts are susceptible to osmotic lysis L forms are wall-less cells that swell into irregular shapes |
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| the plasma membrane |
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| Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane Proteins Selective permeability allows passage of some molecules Enzymes for ATP production Photosynthetic pigments on foldings called chromatophores or thylakoids Damage to the membrane by alcohols, quaternary ammonium (detergents), and polymyxin antibiotics causes leakage of cell contents |
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| fluid mosaic model |
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| Membrane is as viscous as olive oil Proteins move to function Phospholipids rotate and move laterally |
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| facilitated diffusion |
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| Solute combines with a transporter protein in the membrane |
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| movement of materials acros the membrane |
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| Through lipid layer Aquaporins (water channels) |
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| osmotic pressure |
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| The pressure needed to stop the movement of water across the membrane |
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| osmosis |
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| The movement of water across a selectively permeable membrane from an area of high water to an area of lower water concentration |
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| Group translocation: |
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| Requires a transporter protein and PEP |
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| Active transport: |
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| Requires a transporter protein and ATP |
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| cytoplasm |
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| The substance inside the plasma membrane |
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| nuecluotide |
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| Bacterial chromosome |
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| The Prokaryotic Ribosome |
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| Protein synthesis 70S 50S + 30S subunits |
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| Polysaccharide granules Lipid inclusions Sulfur granules |
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| energy reserves |
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| phosphate reserves |
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| Metachromatic granules (volutin) |
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| Gas vacuoles |
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| protein covered cylinders |
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| Magnetosomes |
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| iron oxide destroyes H2O2 |
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| endospopres |
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| Resting cells Resistant to desiccation, heat, chemicals Bacillus, Clostridium Sporulation: Endospore formation Germination: Return to vegetative state |
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| cell wall |
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| Plants, algae, fungi Carbohydrates Cellulose, chitin, glucan, mannan |
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| Glycocalyx |
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| Carbohydrates extending from animal plasma membrane Bonded to proteins and lipids in membrane |
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| plasma membrane |
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| Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Selective permeability allows passage of some molecules Simple diffusion Facilitative diffusion Osmosis Active transport Sterols Glycocalyx carbohydrates Endocytosis Phagocytosis: Pseudopods extend and engulf particles Pinocytosis: Membrane folds inward, bringing in fluid and dissolved substances |
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| Cytosol |
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| Fluid portion of cytoplasm |
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| Cytoskeleton |
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| Microfilaments, intermediate filaments, microtubules |
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| Cytoplasmic streaming |
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| Movement of cytoplasm throughout cells |
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| ribosomes |
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| Protein synthesis 80S Membrane-bound: Attached to ER Free: In cytoplasm 70S In chloroplasts and mitochondria |
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| Nucleus: |
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| Contains chromosomes |
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| ER: |
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| Transport network |
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| Golgi complex |
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| : Membrane formation and secretion |
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| Lysosome |
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| : Digestive enzymes |
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| Vacuole: |
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| Brings food into cells and provides support |
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| Mitochondrion: |
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| Cellular respiration |
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| Chloroplast: |
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| Photosynthesis |
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| Peroxisome: |
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| Oxidation of fatty acids; destroys H2O2 |
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| Centrosome: |
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| Consists of protein fibers and centrioles |
