Block One Text 5

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Block One Text 5
2014-09-25 07:30:06
Test One
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  1. Physical requirements of growth
    Temp (have max, optimum, and min growth temperatures)
  2. What does a refrigerator do?
    The temp inside a properly set fridge will slow the growth of most spoilage organisms and prevent the growth of all but a few pathogenic bacteria
  3. pH: very few bacteria grow at an __
    acidic pH below about pH 4
  4. a.       When bacteria are cultured in lab, they __. These acids are __
                                                                                                                                          i.      The peptones and amino acids  in some media act as buffers, and many media contain __
    1.       Phosphate salts have the advantage of __; they are also nontoxic; in fact, they provide phosphorus, an essential nutrient
    • produce acids that interfere with their own growth
    • neutralized by chemical buffers in the growth medium
    • phosphate salts
    • exhibiting their buffering effect in the pH growth range of most bacteria
  5.                                                               i.      Osmotic Pressure
    1.       Microorganisms obtain almost all their nutrients in solution from the __ and require __for growth (__)
    2.       High osmotic pressures have the effect of __
    a.       When a microbial cell is in a solution whose concentration of solutes is higher than in the cel (the environment is __to the cell), the cellular water __, causing __
    • surrounding water
    • water 
    • their composition is 80-90% water

    • removing necessary water from a cell
    • hypertonic 

    passes out through the plasma membrane to the high solute concentration, causing plasmolysis, or shrinkage of the cell’s cytoplasm
  6. 1.       The growth of the cell is inhibited as the __; and, the addition of salts to a solution can be used to preserve foods
    plasma membrane pulls away from the cell wall
  7. 1.       Most microorganisms must be grown in a medium that is nearly all __
    2.       If the osmotic pressure is unusually low, water tends to __ the cell rather than __. Some microbes that have a relatively weak cell wall may be __by such treatment
    • water
    • enter
    • leave it
    • lysed
  8.                                                               i.      Carbon: __of living matter; needed for all the __ that make up the living cell
    1.       Half the __ of a typical bacterial cell is carbon and a __comes from carbon (chemoheterotrophs do this)
    2.       __ and __ derive their carbon from CO2
    • structural backbone 
    • organic compounds
    • dry weight
    • lot of energy 
    • Chemoautotrophs and photoautotrophs
  9.                                                               i.      Nitrogen, Sulfur, and Phosphorus
    1.       Protein synthesis requires __ and __
    2.       The syntheses of __ and __ also require nitrogen and some __, as does the __
    3.       Nitrogen is about __the dry weight of abackterial cell, and sulfur and phosphorus are about another __%
    • nitrogen and sulfur
    • DNA and RNA
    • phosphorus
    • synthesis of ATP
    • 14% 
    • 4
  10. 1.       Nitrogen: used primarily for the __
    a.       Obtained by __ and reincorporating the amino acids into newly made proteins and other nitrogen-containing compounds
    b.      Also obtained from __
    c.       Some important bacteria use __ directly from the atmosphere in __ and can live freely or cooperatively in symbiosis with the roots of legumes
    • amino group of proeteins
    • decomposing protein-containing material
    • ammonium (NH4+)
    • N2
    • nitrogen fixation
  11. 1.       Sulfur: used to make sulfur-containg amino acids and vitamins like __ and __
    2.       Phospohorus: essential for the synthesis of __ and the __; found in ATP bonds
    a.       Source: phosphate ion
    3.       __(3)__ are also elements that microorganisms require
    • thiamine and biotin
    • nucleic acids and the phospholipids of cell membranes
    • Potassium, magnesium, and calcium
  12. 1.       Elements required in small amounts, like iron and copper
    2.       Most are essential for __ and naturally present in tap water an dother components of media
    enzmy efunction
  13. 1.       __ is a poisonous gas; many current forms of life have metabolic systems that require oxygen for aerobic respiration
    a.       Hydrogen atoms that have been stripped from organic compounds __ to form _, yielding a great deal of energy while __
    • O2
    • combine with oxygen to form water
    • neutralizing a toxic gas
  14. 1.       Microbes that use O2 extract more energy from __than microbes that do not use it. Organisms that require oxygen to lvie are called __.
    They are disadvantaged because -----> __, which grow in the absence of oxygen
    • nutrients 
    • obligate aerobes
    • oxygen is poorly soluble in water of their environment
    • facultative anaerobes
  15. Facultative anaerobes
                                                                                                                                          i.      They can use oxygen when present but can continue growth through fermentation or anaerobic respiration when oxygen is not available 
  16. 1.       __ are bacteria that cannot use molecular oxygen for energy-yielding reactions; most are harmed by it
    Obligate anaerobes
  17. Singlet oxygen
    normal molecular oxygen that has been boosted into a higher energy state and is extremely reactive
  18. Superoxide radicals (superoxide anions): 
    toxic to cellular compoents that all organisms attempting to grow in atmospheric oxgen must produce an enzyme, superoxide dismutase, to neutralize them

    • a.       use oxgen as a final electron acceptor forming water
  19. Peroxide anion
    • located in hydrogen peroxide
    • micrboes have developed enzymes to neutralize it
    • 1.       Human tissue also has catalase

    peroxidase breaks down H2O2
  20. 1.       These toxic forms of oxygen are important in one of the body’s most important defenses against pathogens, which is __, where what happens?
    2.       Obligate anaerobes usually produce neither __ nor __. Because aerobic conditions probably lead to an accumulation of __ in their cytoplasm, obligate anaerobes are extremely sensitive to oxygen
    • phagocytosis
    • ingested pathogens are killed by exposure to these oxidative compounds
    • superoxide dismutase nor catalase
    • superoxide radicals
  21. Aerotolerant anaerobes
    can’t use oxygen but tolerate it; they usually ferment carbohydrates to lactic acid
  22. microaerophiles
    aerobic and do require oxygen
  23. a.       In nature, microorganisms seldom live in the isolated single-species colonies seen on lab plates. They more typically live in communities called __, which was visible with the confocal microscope
    b.      Biofilms reside in a matrix made up primarily of __, but also containing DNA nad proteins, called __
    c.       It can be considered a __, which is a complex polymer containing many times its dry weight in water
    • biofilms
    • polysaccharides
    • slime
    • hydrogel
  24. a.       Cell-to-cell chemical communication, or __, allows bacteria to coordinate their activity and group together into communities that provide benefits similar to multicellular organisms 
    quorum sensing
  25. a.       Within a biofilm community, bacteria can __ and are __
    b.      The close proximity of microorganisms within a biofilm might have the advantage of __
    • share nutrients
    • sheltered from harmful factors in the environment, like dessication, antibiotics, etc.
    • facilitating the transfer of genetic info by, i.e., conjugation
  26. a.       Formation: __
    Extension of biofilmà relocation of some bacteria
    • free-swimming bacteria attaches to surface
    • If grown uniformly-->overcrowded, lack of nutrients, and build up of toxins

    ii. Therefore, they form pillars with channels between them through which water can carry incoming nutrients and outgoing wastes= circulatory system
  27. a.       A nutrient material prepared for the growth of microorganisms in a lab is called a __
                                                                  i.      Microbes that are introduced into a culture medium to initiate growth are called an __. The mirobes that grow and multiply in or on a culture medium are referred to as a __
    • culture medium
    • inoculum
    • culture
  28. a.       Solid media include __, which is good because __.
    •  Agar
    • few microbes can degrade it; it liquefies at 100oC and and remains liquid until about 40oC. For lab, it is held in water baths at about 50oC so as not to injure most bacteria 
  29. a.       Chemically Defined Media (reserved for autotrophic bacteria)
                                                                  i.      For microbes to grow, a medium must provide an __ and __ the organism can’t make
                                                                ii.      This is one whose exact __ is known
                                                              iii.      Organisms that require several growth factors are __and are used in tests to determine the concentration of a particular vitamin in a substance
    • energy source
    •  elements and growth factors 
    • chemical composition
    • fastidious
  30.                                                               i.      Vitamins and growth factors are provided by __ or __
    1.       The soluble vitamins and minerals from the meats or yeasts are __, which is then evaporated so that these factors are concentrated
    2.       Yeast extracts are rich in __
                                                                ii.      If a complex medium is in liquid form, it is called __
                                                              iii.      Wen agar is added, it is a __
    • meat extracts or yeast extracts
    • dissolved in the extracting water
    • B vitamins
    • nutrient broth
    • nutrient agar
  31.                                                               i.      Cultivation of anaerobic bacteria is problematic because anaerobes might be killed by exposure to oxygen. They require __, which contain ingredients that chemically combine with dissolved oxygen and deplete the oxygen in the culture medium
    1.       This is stored in ordinary, tightly capped test tubes and heated before use to drive off oxygen
    reducing media
  32. 1.       Selective media: __
    2.       Differential media: __
    designed to suppress the growth of unwanted bacteria and encourage the growth of the desired microbes

    makes it easier to distinguish colonies from other colonies
  33. a.       Enrichment Culture
                                                                  i.      Used for bacteria present in small numbers and often the case for soil or fecal samples