Micro 2

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Micro 2
2015-10-05 23:58:23

Micro 2
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  1. sterilization
    *the removal or destruction of all microorganisms and viruses on or in a product
  2. Processes to sterilize
    • filtration
    • heat
    • chemicals
    • irradiation
  3. What does it mean for something to be sterile
    • it is free of microbes, including endospores and viruses
    • does not consider prions, they are not destroyed by standard sterilization procedures
  4. What is process of disinfection
    • the elimination of most or all pathogens on or in a material
    • Term generally implies use of antimicrobial chemicals
    • suggests some living microbes may remain
  5. What can disinfectants do?
    • are antimicrobial chemicals used for disinfecting inanimate objects
    • toxic to many forms of life
    • typically targets microorganisms and viruses
    • often called germicides
  6. Germicides
    agents that target microorganisms & viruses
  7. bactericidal
    • includes germicides
    • means they kill bacteria
  8. antiseptics
    • are antimicrobial chemicals non-toxic enough to be used on skin or other body tissue
    • routinely used for invasive procedures like surgery
  9. pasteurization
    • a brief heat treatment that reduces the number of spoilage organisms and destroys pathogens
    • can be done to foods and inanimate objects
  10. decontamination
    a process used to reduce number of pathogens to a level considered safe to handle
  11. Sanitization
    • generally implies a process that reduces microbial population to meet accepted health standards
    • *term does not indicate a specific level of control
  12. preservation
    • the process of delaying spoilage of foods or other perishable products
    • ~can adjust storage conditions to slow microbe growth
    • ~can also add chemical preservates
  13. What is bacteriostatic
    an agent that can inhibit the growth of bacteria but not kill them
  14. What situations warrant microbial control
    • Daily home life
    • foods and food production facilities
    • water treatment facilities
    • hospitals
  15. Healthcare associated infections
    Infections caused by pathogens found in the healthcare setting
  16. aseptic technique
    How does it relate to BSL levels
    • Aseptic technique refers to the use of specific methods to prevent microorganism from contaminating an environment
    • BSL are biosafety levels (1-4) ranging from microbes not known to cause disease (1) to deadly microbes (2)
  17. Which are the highly resistant microbes
    • The endospores Bacillus and Clostridium
    • *Only extreme heat or chemical treatments ensures their complete destruction
  18. What is the D value and what is it used for?
    • D value= decimal reduction time
    • Is the time required for killing 90% of bacterial population under specific conditions
    • Temp of process indicated by subscript ( D121)
    • **Review figuring values pg 111
  19. What environmental conditions can affect death rates in microbe populations?
    • Dirt, grease, and body fluids such as blood can interfere with heat penetration and the action of chemical disinfectants
    • Temp & pH also influence microb death rates
  20. Which instruments pose greater threat of transmission of microbes
    Critical instruments: those that come in direct contact w body tissues. (needles, scalpels)
  21. How does the type of material dictate the sterilization and disinfection procedures
    • Heat treatment can damage many types of plastics & other materials
    • Irradiation provides an alternative to heat, but process damages some plastics
    • Moist heat and liquid chemical can't be used to treat moisture-sensitive material
  22. What physical methods are used to destroy microorganisms and viruses
    • Moist heat
    • Dry Heat
    • Filtration
    • Radiation
    • High pressure
  23. What does high-temp-short-time mean
    What does ultra high temp mean
    • HTST ~ product is held at high heat for a short period of time (ex: pasteurization, used with milk)
    • UHT ~ destroys all microorganism that grow under normal storage conditions, considered "ultra-pasteurization" Ex: heat milk rapidly to extra high temp, hold for few sec, then cool quickly
  24. Autoclaves
    • expensive pressure cooker
    • used to sterilize heat and moisture tolerant items like surgical instruments
  25. What does it mean to be commercially sterile
    • means that the endospores of some thermophiles may survive
    • Ex: canned foods
    • Not usually a concern though cause they grow only at temps well above those of normal storage
  26. What are membrane filters, what do they do
    paperthin filters that have microscopic pores that allow liquid to flow through while trapping particles too large to pass
  27. what are depth filters
    • filters that trap material within thick porous filtration material such as cellulose fibers
    • have complex passages that retain microbes while letting fluid pass
  28. What are HEPA filters
    • High-efficiency particulate air filters
    • remove nearly all airborne particles 0.3μ or larger
    • used in special hospital rooms (ex: for TB pts)
  29. what is electromagnetic radiation
    • a form of energy that travels in waves and has no mass
    • amount of energy is related to the wavelength, which is distance from crest to crest of the wave
    • Ex: radio waves, microwaves, visible and UV rays, x rays, and gamma rays
  30. ionizing radiation & how is it used against microbes?
    • has enough energy to remove electrons from atoms
    • harms cells directly by destroying DNA and damaging cytoplasmic membranes
    • used extensively to sterilize heat-sensitive materials including med equipment, disposable surgical supplies, and drugs like penicillin
  31. What is ultraviolet radiation and how is it used against microbes
    • in wavelengths approx 220 to 300 nm
    • destroys microbes by damaging their DNA
    • actively multiplying organisms are most easily killed
    • bacterial endospores most UV resistant
  32. what are microwaves ~ can they be used against microbes?
    • waves btwn infrared and radio waves
    • do no affect microbes directly, but heat can be lethel
    • Recall, microwave ovens heat unevenly, so even heat-sensitive cells can sometimes survive
  33. how can high pressure be used against microbes?
    • used to decrease # of microbes in commercial foods, like guacamole, w/o using high temp
    • thought to destroy by denaturing proteins and altering cell permeability
    • treated products keep color and flavor w fresh foods
  34. How are germicides grouped according to potency
    • Sterilants
    • High-level disinfectants
    • Intermediate-level disinfectants
    • Low level disinfectants
  35. Sterilants
    • destroy all microorganisms, including endospores and viruses
    • also called sporocides
    • used to treat critical instruments like scalpels
  36. High-level disinfectants
    • destroy all viruses and vegetative microorganism, but do not reliable kill endospores
    • Used on semicritical instruments like GI endoscopes
  37. Intermediate-level disinfectants
    • destroy all vegetative bacteria including mycobacteria, fungi, and most, BUT NOT ALL, viruses
    • Do not kill endospores
    • Used on noncritical instruments like stethoscopes
  38. Low-level disinfectantsLo
    • destroy fungi, vegitative bacteria EXCEPT mycobacteria and enveloped viruses
    • Do not kill endospores, nor destroy naked viruses
    • In hospitals, used for disinfecting furniture, floors, and walls
  39. What points should be considered when choosing a germicide
    • Toxicity
    • Activity in the presence of organic matter
    • Compatibility with the material being treated
    • Residue
    • Cost & availability
    • Storage and stability
    • Environmental risk
  40. What are the germicidal chem groups
    • "Alcohol Always Makes Onry People Horney Because Everyone's Ass & Pussy"
    • Alcohols
    • Aldehydes
    • Biguanides
    • Ethylene Oxide Gas
    • Halogens
    • Metals
    • Ozone
    • Peroxygens
    • Phenolic compounds
    • Quaternary Ammonium Compounds
  41. Alcohols as a germicidal group
    • ethanol and isopropanol
    • Characteristics:
    • Easy to obtain, inexpensive
    • Rapid evaporation limits contact time
    • Uses: antiseptics to clear skin for procedures that break intact skin & disinfectants for treating instruments
  42. Aldehydes for germicide
    • capable of destroying all microbes
    • irritating to respiratory tract, skin and eyes
    • Uses: sterilize med instruments
    • Formalin used in vaccine production and to preserve biological specimens
  43. Biguanides
    • chlorhexidine
    • relatively low toxicity, destroys wide range of microbes, adheres to and persist on skin and mucous membranes
    • Used as antiseptic in soaps, lotions
    • often impregnated in catheters and surgical mesh
  44. Ethylene Oxide Gas as germicide
    • easily penetrates hard to reach places and fabrics w/o damage to moisture sensitive material
    • Is toxic, explosive, carcinogenic
    • commonly used to sterilize med devices
  45. Halogens as germicide
    • chlorine and iodine
    • inexpensive, readily available
    • inorganic compounds neutralize activity
    • Cholrine widely used to disinfect inanimate objects
    • Iodine used as disinfectants or antiseptics
  46. Metals as germicide
    • silver
    • most metal compounds too toxic for medical use
    • used in topical dressings to prevent infection of burns
    • eye drops in newborns prevent eye infections
  47. Ozone
    • unstable form of oxygen readily breaks down into infective form
    • used to disinfect drinking water and wastewater
  48. Peroxygens
    • Hydrogen peroxide/peracetic acid
    • readily biodegradable, less toxic
    • used to sterilize containers for jucies and milk
  49. Phenolic compounds as germicide
    • wide range of activity, reasonable cost, remains effective in presence of detergents
    • Used in variety of personal care products (toothpaste, lotions, deodorant soaps)
  50. Quaternary ammonium compounds
    • non toxic enough to be used on food preparation surfaces
    • widely used to disinfect inanimate object & preserve non-food substances
  51. What are some chemical preservatives that can be used on food items
    • Benzoic, sorbic, propionic acids
    • nitrate
    • affect cell membrane functions
  52. Why is sugar and salt used when canning
    sugar and salt draw water out of cells, dehydrating them
  53. lyophilization
    • freeze-drying
    • food is first frozen, then dried in vacuum
    • water is added to lyophilized material, it reconstitutes
    • food quality is often better than using ordinary methods
  54. catabolism
    processes that harvest energy released during the breakdown of compounds such as glucose, using it to synthesize ATP
  55. what is anabolism
    • Processes that synthesize and assemble the subunits of macromolecules, using energy of ATP
    • Also called biosynthesis
  56. What is the relationship btwn catabolism and anabolism
    • Catabolic processes produce precursor metabolites used in biosynthesis
    • Anabolic processes use the ATP and precursor metabolites produced in catabolism
  57. What is energy
    • the capacity to do work
    • can exist as potential (stored) or kinetic (energy in motion)
    • can never be destroyed
  58. How do photosynthetic organisms get energy
    they harvest energy from sunlight using it to power the synthesis or organic compound from CO

    By doing so, they convert kinetic energy of photons to potential energy of chemical bonds
  59. How do chemoorganotrophs get energy
    by degrading organic compounds, thus they depend on the metabolic activities of photosynthetic organisms
  60. What is the difference btwn exergonic and endergonic reactions?
    • Exergonic reactions: energy is released in the reaction
    • Endergonic reactions: reaction requires an input of energy
  61. What is a metabolic pathway
    • Use a series of sequential chemical reactions to convert a starting compound into intermediates and then, ultimately, into an end product
    • Can be linear, branched or cyclical
    • Actions can be adjusted at certain points, which allows cell to regulate certain processes
    • See Fig 6.4, pg 129
  62. What are enzymes
    What is the substrate
    Proteins that function as biological catalysts, accelerating the conversion of one substance, the substrate, into another, the product
  63. what is activation energy
    • the energy it takes to start a reaction
    • this can be lowered by an enzyme
  64. What is ATP
    • Adenosine triphosphate (ATP) is the main energy currency of cells, serving as the ready and immediate donor of free energy
    • Composed of ribose, adenine, and 3 phosphate groups
  65. What is ADP
    • Adenosine diphosphate
    • What is left after ATP gives energy
    • When an inorganic phosphate group is added, it forms ATP
  66. What kind of reaction happens when making ATP
    What kind of action happens when converted to ADP
    • Cells constantly produce ATP during exergonic reactions of catabolism
    • Cells then use ATP to power endergonic reactions of anabolism
  67. What happens during substrate-level phosphorylation
    the energy released in an exergonic reaction is used to power the addition of an inorganic phosphate (P) to ADP
  68. *recall proton motive force
    is form of energy that results from electrochemical gradient established by electron transport chain
  69. What happens in oxidative phosphorylation
    the energy of a proton motive force which drives the reaction (adding P to ADP)
  70. What is photophosphorylation
    • Process by which photosynthetic organisms generate ATP
    • Uses the suns' radiant energy and an electron transport chain to create a proton motive force
  71. What is the role of the chemical energy source and the terminal electron acceptor~ regarding how cells obtain energy
    • energy source is the chemical that serves as the electron donor
    • The terminal electron acceptor is the one that ultimately accepts those electrons
    • *The greater the difference btwn the electron affinities of energy source and terminal electron acceptor, the more energy released
    • Review pg 130
  72. what are redox reactions
    • also called oxidation-reduction reactions
    • Process by which cells remove electrons from the energy source

  73. Explain oxidized and reduced in regards to oxidation-reducation reactions
    • The substance that loses electrons is oxidized by the reaction
    • The substance that gains those electrons is reduced (think of it as the electron reduced the negative power a little charge a little more)
  74. What are electron carriers?
    What do they do
    carriers that help transfer harvested electrons to the terminal electron acceptor
  75. Name electron carriers
    • NAD+/NADH
    • FAD/FADH2

    Also considered hydrogen carriers, since along with electrons they carry protons
  76. NADH
    • can carry 2 electrons and 1 proton
    • used to generate a proton motive force that can drive ATP synthesis
  77. NADPH
    • carries 2 electrons and 1 proton
    • used in biosynthesis
  78. FADH
    • Carries 2 electrons and 2 protons
    • Also used to generate a proton motive force that can drive ATP
  79. What are the precursor metabolites
    • intermediates of catabolic pathways, used in anabolic pathways
    • serve as carbon skeletons for which subunits of macromolecules can be made
  80. What are the two key processes involved in catabolism of glucose
    • Recall glucose is preferred energy source of many cells
    • Two encompassed processes:
    • 1. Oxidizing glucose molecules to generate ATP, reducing power and precursor metabolites (done by central metabolic pathways)
    • 2. Transferring the electrons carried by NADH and FADH(reducing power) to the terminal electron acceptor (done by respiration and fermentation)
  81. Central metabolic pathways
    • 3 key metabolic pathways
    • gradually oxidize glucose to CO

  82. Why are central metabolic pathways referred to as amphibolic pathways
    • amphi means "both kinds"
    • they have a dual role:
    • Pathways are catabolic, but the precursor metabolites and reducing power they generate also can be diverted for biosynthesis
  83. What are the 3 central metabolic pathways
    • Glycolysis
    • Pentose Phosphate pathway
    • TCA cycle (Tricarboxylic acid)
  84. What happens in glycolysis
    • splits glucose and gradually oxidizes it to form 2 molecules of pyruvate
    • Provides small amount of energy, some reducing power and 6 precursor metabolites
  85. Entner-Doudoroff pathway
    An alternative to glycolysis used by some microbial cells
  86. Pentose phosphate pathway
    • breaks down glucose
    • primary role is production of compounds used in biosynthesis
    • includes reducing power in form of NADPH and 2 precursor metabolites
    • Product of pathway feeds into glycolysis
  87. TCA cycle
    • Tricarboxylic acid cycle
    • prelude to this cycle, transition step converts pyruvate from glycolysis into acetyl-CoA
    • TCA cycle then accepts 2-carbon acetyle group
    • oxidizes it to release 2 CO2

    • Generates most power out of all 3 pathways
    • produce 3 precursor metabolites and ATP
  88. What happens during respiration
    uses the reducing power accumulated in the central metabolic pathways to generate ATP by oxidative phosphorylation
  89. What is aerobic respiration
    uses Oas a terminal electron acceptor
  90. What is anaerobic respiration
    uses a molecule other than Oas a terminal electron acceptor
  91. What does fermentation solve
    • Cells that cannot respire are limited in ability to recycle reduced electron carriers
    • If electrons aren't moved from reduced carriers, none will be available to accept electrons
    • no more glucose molecules can be broken
    • solves this problem

    *respire = respiration
  92. How does fermentation solve the problem
    • uses pyruvate of a derivative as a terminal electron acceptor
    • recycles the NADH
  93. What suffix do all enzymes share
  94. What happens at the active site
    • the active site is a small crevice where substrate binds
    • binding causes shape of enzyme to change slightly
  95. what is induced fit
    • a mutual interaction btwn substrate and enzyme
    • creating enzyme-substrate complex
  96. what are cofactors
    a non-protein components that assistant enzymes
  97. What are coenzymes
    • organic cofactors that function as loosely bound carriers of molecules or electrons
    • include electron carriers FAD, NAD, and NADP
  98. What do coenzymes do
    • transfer substances from one compound to another
    • some remain bound to enzyme during transfer
    • some separate from enzyme, carrying substance being transferred w them
    • some can assist different enzymes
  99. What are coenzymes derived from
    most are derived from vitamins
  100. How does temp, pH and salt affect enzymes
    • each enzyme has narrow range of conditions which it works in best
    • Temp can affect speed of reactions
    • most operate best in low salt 
    • most operate in pH values slightly above 7
  101. What are allosteric enzymes?
    • enzymes that the cell can control
    • they have an allosteric site as well as an active site
  102. What happens when a molecule binds with the allosteric site
    • the shape of the enzyme changes
    • in some cases it enhances the affinity for the substrate
    • in other cases it decreases it
  103. How does feedback inhibition work?
    • allosteric enzymes generally catalyze 1st step of pathway
    • if pathway is biosynthetic, end product generally acts as allosteric inhibitor (which is feedback inhibitation)
    • allows cell to shut down a pathway when the product begins accumulating
  104. What happens during competitive inhibition
    the inhibitor binds to the active site of the enzyme, blocking access of the substrate to that site
  105. What happens during non-competitive inhibition
    • occurs when inhibitor binds to a site other than active site
    • binding changes enzyme shape so substrate can't bind to active site
    • except for allosteric inhibitors, non-competitive inhibition is permanent
  106. What do central metabolic pathways generate
    • ATP by substrate-level phosphorylation
    • Reducing power in the form of NADH, FADH, and NADPH
    • Precursor metabolite
  107. What happens in the glycolysis pathway
    • Generates:
    • 2 ATP 
    • 2 NADH + 2 H+
    • 6 different precursor metabolites
  108. What are 2 phases of glycolysis
    • Investment or preparatory phase
    • Pay-off phase
  109. What happens in glycolysis investment/preparatory phase
    • consumes energy by transfering hi-energy P to 6-carbon sugar
    • 6 carbon sugar than split to yield 2 3-carbon mol, w phosphate
  110. Pay off phase of glycolysis
    • oxidizes and rearranges 3-carbon molecules, generating 1 NADH and 2 ATP
    • ultimatily forms pryuvate
  111. For each molecule of glucose, what does glycolysis produce
    • 2 molecules ATP, net gain
    • (4 ATP are made, but costs 2 in investment)
    • 2 NADH + 2 H+
    • 5 intermediates as well as end product, pyruvate
  112. Why is the pentose phosphate pathway important
    it contributes to biosynthisis
  113. What does pentose phosphate pathway generate
    • varies, depending on which of several possible atlernatives
    • Produces:
    • Reducing power ~ variable amount of NADPH produced
    • Precursor metabolites~ two intermediates are precursor metabolites
  114. What is the transition step
    • links glycolysis and pentose phosphate pathway to TCA cycle
    • converts pyruvate to acetyl-CoA
  115. What does transition step produce
    • repeated twice
    • produces 2 NADH + 2 H
    • end product is precursor metaboite
  116. how does eukaryotic cells get pyruate to the trasition step
    must transport pyruate molecules into mitochondria for the transition step to occur
  117. what is the yeild of the transition yield
    • reducing power: 2 NADH + 2 H
    • Precursor metabolites ~ one precursor metabolite
  118. what happens during TCA cycle
    completes oxidation of glucose
  119. What does TCA generate
    • 2 ATP
    • Reducing power: 6 NADH + 6 H AND 2 FADH
    • 2 intermediates
  120. what are the two processes of oxidative phosphorylation