Dr. Dannelly’s BIO274 – Flashcards
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| Differential media |
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| Make it easy to distinguish colonies of different microbes Different colors |
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| Selective media |
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| Suppress unwanted microbes and encourages desired microbes Staphylococcus aureus can grow on both differential and selective media too. It is differential because of menotal(type of sugar) and pH indicator(which turn media yellow from a red color, red at pH of 7, yellow when it is acidic) It is selective because the specific media they use is 7.5% salt which Staph is the only microorganism that grow in those conditions. |
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| Blood agar |
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| Uses the blood from sheeps(red blood cells) Hemolysin=breaks red blood cells(can cause damage to other cells too) Basically this is seeing if the microorganism can cause damage to the sheep's red blood cells. Farms that have sheeps on it that are only used as blood donors for this type of media Complete hemolysis(beta hemolysis clear zone), and partial hemolysis(alpha hemolysis Green zone) Streptococcus hemolysis' the red blood cells |
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| Enriched culture |
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| Encourages growth of desired microbes Assume a soil sample contains a few phenol-degrading bacteria and thousands of other bacteria Inoculate phenol-containing culture medium with the soil, and incubate Transfer 1ml to another flask of the phenol medium, and incubate Transfer 1ml to another flask of the phenol medium, and incubate Only phenol-metabolizing bacteria will be growing Example: if you want to find an organism that can break down something such as a phenol or oil, make a culture with the specific thing you are looking for(phenol or oil) |
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| Obtaining pure cultures |
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| A pure culture contains only one species or strain A colony is a population of cells arising from a single cell or spore or from a group of attached cells A colony is often called a "Colony-forming unit" (CFU) The streak plate method is used to isolate pure cultures |
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| Understanding the bacterial growth curve |
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| Lag phase-intense activity preparing for population growth, but no increase in population Shortest lag you can have is 1.5-2 hours You can't get rid of this phase, something about spreading cells out that makes them still go through lag phase Log phase-logarithmic, or exponential increase in population Stationary phase-period of equilibrium; microbial deaths balance production of new cells Cells will always go through this phase too. During stationary phase, microbes are more resistant to antibiotics Normal cells stop when they touch another cells, cancer cells lose that mechanism that tells them to stop replicating when they touch, tumors form because they are too crowded Death phase-population is decreasing in a logarithmic rate. First microbes to die are usually the first cells "born", oldest die first |
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| Spectrophotometer |
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| Measures the amount of light that goes through the test tube of liquid broth culture. Can't measure the death phase with the spectrophotometer because their dead cells are still in the broth and it still absorbs light Percent transmittence=how much light that goes through the liquid broth culture. They plotted the growth of microorganisms that grew in the liquid culture and came up with a graph that didn't "look" like it was growing, so they took the reciperacle of the numbers and came up with a graph that "looks" like it grew. |
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| Sepsis |
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| Refers to microbial contamination |
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| Asepsis |
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| The absence of significant contamination Working without significantly contaminating wound Aseptic surgery techniques prevent microbial contamination of wounds |
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| Sterilization |
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| Removing ALL microbial life ALL life is gone NO degrees of steril, it is either steril or not If it has only 1 microbe, it is not steril anymore |
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| Disinfection |
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| Removing pathogens from inanimate objects |
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| Antisepsis |
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| Removing pathogens from living tissue Same substance as disinfectant, just uses lower strenght so it doesn't hurt skin |
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| Sanitation |
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| Lowering microbial counts on eating utensils Government dictated |
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| Biocide/germicide |
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| Killing microbes Cide=to kill |
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| Bacteriostasis |
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| Inhibiting, not killing, microbes Stasis=to inhibit, but not kill Different products might kill bacteria, but only inhibit virus, you need to read the side of the bottles |
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| Effectiveness of treatment |
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| Depends on: -Number of microbes-more that you start with, the longer it takes to kill them -Environment(organic matter, temperature, biofilms) -Time of exposure -Microbial characteristics -pH Organic material(fecal matter) binds to chlorine and neutralizes it, it ends up breaking down the sheets, hospitals have enormous laundry bill because of this Some won't "clean" up vomit because of the low pH environment |
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| Actions of microbial control agents |
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| Alteration of membrane permeability Damage to proteins Damage to nucleic acids(DNA) |
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| Thermal death point(TDP) |
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| Lowest temperature at which all cells in a culture are killed in 10 minutes Sporeformers-120C is the TDP |
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| Thermal death time(TDT) |
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| Time during which all cells in a culture are killed |
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| Decimal reduction time(DRT) |
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| Minutes to kill 90% of a population at a given temperature |
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| Moist heat sterilization |
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| Moist heat denatures proteins Autoclave: steam under pressure |
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| Steam sterilization |
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| Steam must contact item's surface |
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| Pasteurization |
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| Reduces spoilage organisms and pathogens (usually liquids) Equivalent treatments -63C for 30 minutes -High-temperature short-time: 72C for 15 seconds -Ultra-high-temperature:140C for <1sec -Thermoduric organisms survive Capris Sun=growing fungus inside |
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| Dry heat sterilization |
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| Kills by oxidation(high levels of oxygen added) -Dry heat -Flaming -Incineration -Hot-air sterilization Hot-air=170C for 2 hours Autoclave=121C for 15 minutes |
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| Filtration |
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| HEPA removes microbes >0.3 Membrane filtration removes microbes>0.22 Used to keep microbes out of a certain area, not used to kill |
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| Physical methods of microbial control |
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| Low temperature inhibits microbial growth(doesn't necessarily kill microbes, but it stops growth) -Refrigeration -Deep-freezing -Lyophilization High pressure denatures proteins Desiccation prevents metabolism Osmotic pressure causes plasmolysis High sodium diets-skin secretes salt, good in a way because if you touch something that has E.coli or something that doesn't like salt, it will not survive, Staph will survive though |
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| Radiation |
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| Ionizing radiation(X rays, gamma rays, electron beams) -Ionizes water to release OH* -Damages DNA Nonionizing radiation(UV, 260nm) -Damages DNA Microwaves kill by heat, not especially antimicrobial Kills some but not all microbes, least effective way |
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| Principles of effective disinfection |
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| Concentration of disinfectant Organic matter(sneeze vs. vomit) pH Time-Time increases, death of organisms increases 100% ethanol won't kill microbe because of the semipermeable membrane, it doesn't want the ethanol in, so it doesn't let it in. You have to add some water to the ethanol in order for it to kill microbes, it will let the water into the cells, but the water carries some ethanol with it, it ruptures the cell |
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| Zone of inhibition |
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| Zone around a disk of an antibiotic where the microbes do NOT grow |
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| Phenol and phenolics |
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| Disrupt plasma membrane Phenol is the "gold standard" of disinfectants and other disinfectants are often compared to phenol to rate their effectiveness |
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| Bisphenols |
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| Hexachlorophene, tricosan -Disrupt plasma membrane |
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| Biguanides |
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| Chlorhexidine Disrupts plasma membrane |
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| Halogens |
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| Iodine -Tinctures: in aqueous alcohol -Iodophors: in organic molecules -Alter protein synthesis and membranes Chlorine -Bleach:hypochlorous acid (HOCl) -Chloramine:chlorine+ammonia -Oxidizing agents Swab arm with iodine before shot because this kills natural flora. If natural flora gets deep in skin, it can cause problems |
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| Endospores |
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| Hardest bacteria to kill overall Only forms in certain bacteria Once endospore is formed, it is easily spread by air/wind Very heat resistant, hard to kill, adverse environments Puts membrane and peptidoglycan around the new cell DNA |
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| Eukaryotic cells |
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| Chloroplast=energy making body Protazoa uses vacuoles to drink Major difference is membranes Flagellum is different in prokaryotes and eukaryotes Eukaryotes flagella whip like a tail, more advanced |
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| The cell wall and glycocalyx |
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| Cell wall -Plants, algae, fungi -Carbohydrates Cellulose, chitin, glucan, mannan Glycocalyx -Carbohydrates extending from animal plasma membrane -Bonded to proteins and lipids in membrane Long chain sugars(carbohydates) that are bound to cell |
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| Plasma membrane |
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| Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Proteins in membrane are what make a prokaryote and a eukaryote cell Selective permeability allows passage of some molecules Simple diffusion Facilitative diffusion Osmosis Active transport Endocytosis -Phagocytosis:(cell eating)pseudopods extend and engulf particles, process of eating, pulling something into cell via pseudopod -Pinocytosis:(Cell drinking)membrane folds inward, bringing in fluid and dissolving substances, drinks fluids and dissolved substances-ameba |
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| Cytoplasm membrane |
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| Everything inside plasma membrane and outside nucleus Same for prokaryote and eukaryote cells |
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| Cytosol |
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| Fluid portion of cytoplasm Only fluid If you spin a centrifuge 105,000 times gravity you will separate the cytosol |
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| Cytoskeleton |
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| Microfilaments, intermediate filaments, microtubules All run on cell-use networks to move things in cell |
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| Cytoplasmic streaming |
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| Movement of cytoplasm throughout cells When the pseudopod stretches out, the cytoplasmic streaming is basically the movement of the rest of the cell to catch up with the pseudopod |
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| Ribosomes |
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| Protein synthesis 80S Ribosomes(eukaryotes) Membrane-bound:attached to ER Free in cytoplasm 70S Ribosomes(Prokaryotes) In chloroplasts and mitochondria(These used to be bacteria, evolutionarly speaking) |
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| Nucleus |
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| Contains chromosomes |
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| Lysosome |
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| Digestive enzymes Found in phagocyte cells(white blood cells) Bag of enzymes Digest bacteria to protect you |
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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 Energy=ATP |
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| Chloroplast |
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| Photosynthesis Gives cell energy-plant cell |
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| Peroxisome |
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| Oxidation of fatty acids; destroys H2O2 Breaks down fat and destroys peroxide-white blood cells make peroxide Peroxide kills both bacteria and cells-so your body has to have a way to protect itself from the peroxide too. |
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| Endosymbiotic theory |
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| Mitochondria has DNA that is the same as DNA of bacteria. Our cells(eukaryote) have long paired chromosomes(DNA) and our cells have DNA in mitochondria that is like bacteria DNA Has control mechanisms in DNA that we don't have, convincing that our mitochondria is the same as bacteria |
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| Metabolism |
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| The sum of the chemical reactions in an organism |
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| Catabolism |
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| Provides energy and building blocks for anabolism Get energy-breaking down food and get nutrients(carbon intermediates) and energy Breaks down food to get ATP Transfer energy from complex molecules to ATP, heat is released |
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| Anabolism |
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| Uses energy and building blocks to build large molecules Building up-use engergy from catabolism makes cell parts Use ATP to make cell parts, heat is released |
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| Metabolic pathways |
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| A sequence of enzmatically catalyed chemical reaction in a cell Metabolic pathways are determined by enzymes Enzymes are encoded by genes |
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| Collision theory |
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| States that the chemical reactions can occur when atoms, ions, and molecules collide(exactly right confirmation-angle and speed) May hit each other more than once before they bond Organic catalysts=made of proteins, speed up reaction. Not used up, can turn around and be used again. It grabs and puts them in just the right configuration to let them bond everytime |
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| Activation energy |
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| Needed to disrupt electric configuration Amount of energy involved to get reaction to happen, get right confirmation to bond Enzyme lowers activation energy, speeds up reaction Cells can't survive without enzymes They can speed up the reaction by 1x10 to the power of 20, wouldn't survive without this, very efficient and speedy |
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| Reaction rate |
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| The frequency of collisions with enough energy to bring about a reaction Reaction rate can be increased by enzymes, or by increasing temperature or pressure |
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| Biological catalysts |
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| Enzymes Specific for a chemical reaction; not used up in that reaction |
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| Apoenzyme |
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| Protein portion Inactive until cofactor comes along |
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| Cofactor |
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| Nonprotein component(not all enzymes have a cofactor) Can modify, carry electrons Activator |
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| Holoenzymes |
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| Apoenzyme plus cofactor |
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| Important coenzymes |
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| NAD+ NADP+ FAD Above 3 are all electron carriers in cell Coenzyme A |
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| Oxidoreductase |
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| Oxidation-reduction reactions-takes one electron and gives to another atom Major category of enzymes |
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| Transferase |
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| Transfer functional groups Vast group Major category of enzymes |
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| Hydrolase |
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| Hydrolysis Vast group breaking a molecule-add water to bond to break it Major category of enzymes |
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| Lyase |
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| Removal of atoms without hydrolysis Don't tear apart Major category of enzymes |
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| Isomerase |
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| Rearrangement of atoms Major category of enzymes |
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| Ligase |
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| Joining of molecules;uses ATP Building up of molecules Put DNA back together with this Major category of enzymes |
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| Factors influencing enzyme activity |
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| Temperature(out of range temps denature proteins) pH(out of rang pH denatures proteins) Substrate concentration At body temperature, protein is folded up correctly. If we were to take proteins out of body, and heated it up, they would start to unfold Adult brain at 107F starts to cook(unfolding of proteins), temp is lower in babies Slows growth of bacteria when we heat tempuratures If protein unfolds all the way, it is over, can't be refolded Glutenation-sticks together |
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| Acidophiles |
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| Grow in acidic places (pH of 5) |
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| Temperature curve for an enzyme |
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| Tells you what temperature an enzyme is most active(37C) You would have to run multiple cultures at multiple temperatures in separate tubes in order to get the curve Environmental pathogens grow best at 22C(room temp) |
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| Why is the curve above asymmetrical? (temperature curve for an enzyme) |
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| The protein is irreversibly denatured due to heat |
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| What is a boichemical pathway? |
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| Set of enzymes-work in order-make product and uses it's enzyme for next reaction and so on Metabolic pathway-sequence of enzymatically catalyzed chemical reaction in a cell Metabolic pathways are determined by enzymes They are necessary to make products for use by the cell -In anabolic pathways, the compounds being worked through the pathway will ultimately be the product that the cell will use -In catabolic pathways, the cell is breaking down compounds, such as sugars(food sources), and energy is being stored as ATP, or you could say ATP is being made |
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| Glycolosis |
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| Starts with 6 carbons and ends with (2) 3 carbon compounds Ends with pyruvic acid 2 NADH-electron transport molecules(will yeild more energy) |
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| Alcohols |
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| Ethanol, isopropanol(rubbing alcohol) Denatures proteins, dissolve lipids Requires water Remember Gram-negative cells decolorization step Not good to do, but if you pour alcohol on a wound, it forms a false membrane over wound, bacteria can survive under false membrane. Becomes hard to treat wound after this too. Pure alcohol evaporates too quickly to work Alcohol is hydroscopic=sucks up water |
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| Heavy metals |
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| Ag, Hg, and Cu prevent microbial growth Silver nitrate may be used to prevent gonorrheal ophthalmia neonatorum(put in babies eyes when they are first born to prevent gonorrhea of the eye) Silver sulfadiazine used as a tropical cream on burns Copper sulfate is an algicide Oligodynamic action-stainless steal sinks prevent microbial growth -Denatures proteins |
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| Suface-active agents, or surfactants |
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| Soaps and detergents don't kill germs, you are mechanically washing them off your hands-Keeps cutting the numbers down If it says anti-microbial soap then it has an agent to kill microbes Triclosine=good stuff, this is the anti-microbial stuff they put in the soap, lots of people are allergic to it though Found in Dial soap, bright yellow |
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| Chemical food preservatives |
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| Organic acids Inhibit metabolism Sorbic acid, benzoic acid, and calcium phopionate -Makes product more acidic to inhibit metabolism of foods to help inhibit growth The microbes will overcome eventually the acids, you will know because of the smell Nitrite-prevents endospore germination, but it is a carcinogen-found in bacon Antibiotics Nisin and natamycin prevent spoilage of cheese Help after cheese is done, antibiotic gets completely distroyed in stomach |
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| Aldehydes |
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| Inactive proteins by cross-linking with functional groups(-NH2, -OH, -COOH, -SH) Use: medical equipment -Glutaraldehyde, formaldehyde(preserves and prevents microbial growth), and ortho-phthalaldehyde |
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| Gaseous sterilants |
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| Denatures proteins Use: heat-sensitive material -Ethylene oxide More expensive than autoclaves You can use this to sterilize equipment that can't handle the moist heat environment |
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| Order of resistance of microorganisms to chemical biocides |
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| Most resistant to least resistant: -Endospores of bacteria -Mycobacteria -Cysts of protozoa -Vegetative protozoa -Gram-negative(because of the two membranes) -Fungi, including most fungal spores -Viruses without envelopes -Gram positive bacteria -Viruses with lipid envelopes(membrane) |
