Lab Final Flashcards

(60 cards)

1
Q

Logarithmic Graphs are used to…

the dependent variable plots as…

…when it is proportional to…

A
  • represent large numbers in a short space
  • a straight line
  • a constant power of the
    independent variable.
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2
Q

Semi-logarithmic Graphs are used when…

A

successive values of one quantity increase in geometric

progression as another quantity increases in arithmetic progression.

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3
Q

Linear Scale Graphs are used when…

A

relationships are in non-geometric progression.

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4
Q

The independent variable belongs on the

The dependent variable belongs on the

A

x-axis (horizontal line)

y-axis (vertical line)

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5
Q

What is bolded in a figure/graph

A

Table 1/Figure1

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6
Q

Where does the title go:
on a graph =
on a table =

A
graph = title below
table = title below
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7
Q

What is the difference between a logarithmic and semi-logarithmic graph?

A

Log graphs have x & y axis as log functions (also used when we have large values in a small scale)
Semi-log graphs have either x or y as log functions (also used when one value is progressing geometrically but the other is progressing arithmetically)

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8
Q

True or False:

Dependent variables are plotted on the abscissa

A

False, the independent variable is plotted on the abscissa

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9
Q

x axis =

y axis =

A
x = abscissa = independent
y = ordinate = dependent
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10
Q

practice quiz 1 question 3

A

plzzzz don’t u want a big fat throbbing AAAAA

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11
Q

practice quiz 1 question 4

A

plzzzz don’t u want a big fat wet AAAAA

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12
Q

What is calibration? Explain calibration relative to photospectrometry:

A

Calibration is comparing what you have to what is known in order to set a standard/control in an experiment without calibration in photospectrometry values would be inaccurate

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13
Q
True or False:
Working distance (distance between the objective and the slide where the slide is in focus) of the microscope increases as the magnification power of the objective lens increases
A

False

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14
Q

The revolving power improves by changing the yellow light source to (red or violet)

A

violet

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15
Q

resolving power equation

A

d = lambda / (NAoc - NAobj)

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16
Q

Higher wavelength means _____ resolving power

A

lower

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17
Q

the resolution can improve with the increase or decrease in numerical aperture

A

increase

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18
Q

monochromatic

A

light of one wavelength/nm (incident beam Io)

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19
Q

True or False:

A standard curve can be established by measuring the absorbance of a solution at various concentrations

A

True

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20
Q
  • Cell fractionation is…

- by either…

A
  • …a general procedure that consists of disrupting the cell membrane (and cell wall of plants) to release the cell contents and then separate the organelles based upon differences in size or density
  • …differential centrifugation or density gradient centrifugation.
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21
Q

isoelectric point (pI) =

A

the pH at which a particular molecule carries no net electrical charge or is electrically neutral

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22
Q

At a pH below their pI, proteins carry…

At a pH above their pI, proteins carry…

A

…a net positive charge

…a net negative charge.

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23
Q
  • @ its pI, proteins are at their…

- Therefore, by changing the pH of the solution to the pI, the…

A

…lowest solubility (due to net 0 charge)

…solubility of the protein will be lowered

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24
Q
  • As the salt concentration is increased…
  • Further increases in the salt concentration result in…
  • Finally, the protein starts to…
  • This phenomenon of protein precipitation in the presence of excess salt is known as…
A

… a point of maximum protein solubility is usually reached
…fewer water molecules available to solubilize protein (since the water molecules are being used to solubilize the salts)
…precipitate when there is not a sufficient number of water molecules to interact with (solubilize) the protein molecules
…salting-out.

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25
- At low salt concentrations... | - This is commonly known as...
...the presence of salt stabilizes the various charged groups on a protein molecule, thus attracting the protein into the solution and enhancing the solubility of protein. ...salting-in.
26
the role of temperature in fractionation of cellular components such as chloroplasts, mitochondria and proteins =
cold to stop enzyme reactions/maintain the integrity of the organelles and enzymes during the fractionation procedure
27
some factors that can effect protein function:
pH, temperature, fixation, etc
28
Lowry Assay Methods:
1. ) Prepare a series of BSA protein standards from 0.8 to 0.025 mg/ml 2. ) Prepare your unknowns (from lab 7) according to instructor specifications. (Try diluting S1b and S2 to 1/10 concentration by separately adding 100 μl of the each protein solution to 900 μl of HB. Dilute the resuspended microfibil pellet to 1/10 concentration by adding 100 μl of HB to 900 μl of FRB. Save the remainder of each protein extraction for a future lab). 3. ) Prepare 15 ml tubes by labeling them as either BSA concentration, blank or unknown (10 tubes total). Add 1.5 ml of Solution A to each tube then 1.0 ml of either BSA, diluted unknown, or deionized water to the appropriately labeled tube. 4. ) Let the solutions sit for 15 minutes at room temperature. 5. ) During this time dilute 5 ml of Solution B with 5 ml of H20. It is now at 1.0 N. (There will be an aliquot of diluted Solution B under the fume hood. Only do this step if there is not enough dilute Solution B in the aliquot). 6. ) Add 0.4 ml of Solution B to each tube. 7. ) Let the solutions sit for 15 min at room temperature. (Precipitate may form at the bottom of the tubes. If so do not resuspend the precipitate or pipette it into the curvette in the next step.) 8. ) Read all of the absorbances in the Spec 20 at a wavelength of 580 nm (Curvettes are full at 2.5 ml solution. Do not overfill them. Be sure to calibrate using the blank between measurements.) 9. ) Plot a standard curve. 10. ) Calculate the protein concentrations for each of the unknowns
29
Bradford Assay is based on... When the dye binds to the protein... The amount of light absorbance at a wavelength of 595 nm is directly proportional to...
- the simple binding affinity for a particular dye (Bio Rad Protein Assay Dye) to protein. - it changes from red to blue. - the amount of protein
30
Beer's Law
The amount of light absorbance at a wavelength of 595 nm is directly proportional to the amount of protein
31
In isoelectric focusing, the proteins migrate...
along a pH gradient
32
LDH staining is used to show
enzymatic activity
33
With native gel electrophoresis, the proteins are subjected to... The proteins will then separate based on their...
...an electrical field while in an agarose gel ...inherent charges
34
Buffers in gel electrophoresis are used to
provide ions that carry a current and to maintain the pH at a relatively constant value
35
2 gels in one run = The first gel... The separating gel then allows for...
= discontinuous gel electrophoresis ...“stacks the proteins” (condenses the protein), so that all of the proteins meet the second gel (i.e., the separating gel) all at the same time. ...separation based on molecular weight
36
(Gel Electrophoresis) positive ions go to = negative ions go to =
``` + = cathode (negatively charged) (blue) - = anode (positively charged) (red) ```
37
(Non-Native Electrophoresis) | Factors that affect the mobility
charge and size
38
Histochemistry =
= the utilization of various stains and chemical staining procedures to visualize where specific cellular components are located in tissue sections (or thin layers of cells)
39
The basic steps in histotechnique: (4)
1. ) The tissue or organ is removed from the organism and preserved = FIXATION 2. ) The fixed tissue is sectioned (thinly sliced) using a microtome = SECTIONING 3. ) The sectioned tissue is placed on a microscope slide and stained = STAINING 4. ) The stained tissue sections are then permanently mounted = MOUNTING
40
Immunohistochemistry is simply...
an advanced histochemical procedure that utilizes antibodies to detect specific proteins of interest
41
Immunohistochemistry basic steps are the same as... except that...
...histotechnique ...the staining procedure utilizes the primary and secondary antibodies and a final reporter protein for visualization of the antibody-antigen complex, usually horseradish peroxidase, alkaline phosphatase, or a fluorochrome (i.e., a fluorescent molecule) [rhodamine (red) and fluorescein (green) are commonly used].
42
In our gel fractionation procedure, did we use differential centrifugation or density gradient centrifugation?
Both
43
In comparison to the particles present in the post-chloroplast supernatant, the particles present in the post-mitochondrial supernatant will generally have greater or smaller sedimentation coefficient?
smaller
44
protein A salts out at 30% ammonium sulfate, while protein B salts out at 70% ammonium sulfate. Which protein has a higher solubility in water?
protein B
45
purpose of the Lowry assay:
To quantify proteins based on their solution absorbance and comparing it to a standard curve. Also to "normalize" the amount of starting protein material for subsequent assays.
46
Purpose of sucrose in homogenization buffer
aids in stabilizing the pH of the solution and maintains the integrity of the structures by reducing the chances of osmosis.
47
What technique is used during the Lowry assay to quantify protein? differential centrifugation photospectrometry light microscopy
photospectrometry
48
why is protein quantification important?
it attempts to "normalize" the amount of starting protein material for subsequent assays.
49
True or False: | the standard curve is established by measuring the transmittance of the solution at various concentrations.
True | transmittance = absorbance
50
Why do we blank/zero at every wavelength, prior to measuring the absorbance of the colored solution?
in order to calibrate the spectrophotometer. without this, the absorbance values would be inaccurate.
51
- Cell fractionation is... | - by either...
- ...a general procedure that consists of disrupting the cell membrane (and cell wall of plants) to release the cell contents and then separate the organelles based upon differences in size or density - ...differential centrifugation or density gradient centrifugation.
52
differential centrifugation = the homogenate is...
= the homogenate is centrifuged repeatedly at successively higher speeds, sedimenting progressively smaller particles.
53
density gradient centrifugation = the homogenate is... - As the tube spins... - The topmost layer contains... - Afterwards...
= the homogenate is added to the top of a centrifuge tube that contains a sucrose gradient in which the most concentrated (most dense) sucrose solution is at the bottom of the tube and the least concentrated (least dense) sucrose solution is at the top. - ...the organelles distribute themselves in the sucrose gradient by size, the largest organelles sedimenting most rapidly - ...the cytosol - ...the cell fractions are removed by puncturing the bottom of the tube and allowing the contents in each layer to drip into a separate test tube
54
The sedimentation coefficient =
= a physical constant frequently encountered in biological literature
55
A particle’s sedimentation coefficient(s) is determined from...
...its rate of sedimentation under conditions of unit acceleration.
56
The factors that determine how rapidly a particle sediments in a centrifugal field are: (2)
1. ) the particle’s radius | 2. ) its effective density (the difference between its density and the density of the liquid through which it is moving)
57
In general, the _____ the particle, the ______ its sedimentation coefficient will be
larger | greater
58
The force generated by the centrifuge is expressed as... | With units...
...a relative centrifugal force (RCF) | ...“g” being the force of the earth’s gravity exerted upon a mass
59
RCF =
= a function of the speed of centrifugation in revolutions per minute (rpm) and the distance of the particle from the axis of rotation.
60
the purpose of an cold isotonic homogenization buffer in the fractionation of chloroplasts and mitochondria = (3)
1. ) cold to stop enzyme reactions/maintain the integrity of the organelles and enzymes during the fractionation procedure 2. ) isotonic to stop osmosis 3. ) buffer to stop pH changes