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25 Cards in this Set
- Front
- Back
Means of introducing new genetic material into bacterial cells:
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Conjugation
Transduction Transformation |
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Conjugation-
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Mating involving F(+) cell (or Hfr cell) and F(-) cell.
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Transduction-
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The infection of a bacterium by a bacterial virus (bacteriophage)
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Transformation-
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Which is stable introduction of free DNA into the bacterium.
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Antibiotic:
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-Defined as a metabolic product of one organism that, inu very small amounts, is detrimental or inhibitory to microorganisms.
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Light Source-
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This is built into the base with a lens that focuses light onto the condenser underneath the stage.
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Condenser-
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If present, this contains a system of lenses that focuses light on the object placed on the stage. Condensers can be either movable or fixed.
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Iris Diaphragm-
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Used to adjust the amount of light striking the object. It can be opened or closed using the lever on the side of the condenser.
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Stage-
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Holds the slide to be viewed. The stage can be moved verticall by turning the coarse adjustment knob and the fine adjustment knob.
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Stage clips-
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HOlds teh slide so that it can be moved by hand.
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Base and arm-
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These support parts of the microschope; these also allow for easy carrying and stability during use.
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Objective lenses-
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Mounted on a revolving nosepiece or turret. Most new microscopes are parfocal; that is, when an object is in focus with one lens, the lenses can be changed without completely losing focus. Each objective contains a complex lens system. The lens closest to the specimen produces the magnification. Magnification is indicated on the side of the objective.
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Resolving power (R) is dependent on what three factors?
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-Angular aperture(θ)
-Refractive index(n) -Wavelength of light(λ) |
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Angular aperture-
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Note the cone of ligth entering the objective. The optimum value for θ is the angle that produces a cone of light whose diameter just matches the diameter of the objective.
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Refractive index-
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The medium through which the light must travel will affect the shape of the cone of ligth that thus resolution. Air has a refractive index of n=1. Oil has a greater refractive index than air (n=1.5) and is often used to increase resolution of the microscope at higher powers by increasing the angle of teh cone of light that passes into the objective.
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Wavelength of light(λ)
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The shorter the wavelength of light, the greater is the resolution of the objective. The value of λ can be changed by using colored filters.
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Resolving poer expression:
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R= λ/(2(n * sin θ))
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Numerical aperture (NA)
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(n * sin θ)
R= λ/(2NA) |
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Osmosis-
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Specialized type of diffusion. It is the process where water diffuses from high water content (low solute) to low water content (high solute).
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Hypertonic-
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The solution on one side of the membrane contains a greater concentration of substance compared to the other.
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Isotonic-
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Equal amounts of the substance are found on each side of the membrane.
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Hypotonic-
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The solution on one side of the membrane contains a lower concentration of a substance compared to the other.
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Diffusion-
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Substances may move across the membrane by diffusion. In the context of memebranes, diffusion is the movement of molecules across a membrane from areas of high concentration to areas of low concentration.
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Simple diffusion-
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Where the diffusing substance passes directly through the phosopholipid bilayer.
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Facilitated diffusion-
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Diffusing substance is helped across the tightly packed hydrophobic interior of the bilayer by a specific transport protein.
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