Lab Exam Flashcards

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1
Q

equipment

A

distance: 15 cm ruler
weight: electronic balance
volume: graduated cylinder
- pipette - come in 10 ml, 2 ml, and 1 ml
- micropipette - to measure 1 ml or less
2-20 uL
20 - 200 uL
100 - 1000 uL
microscope

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2
Q

accuracy

A

measure of how close measured values come to true value

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3
Q

precision

A

measure of consistency and sometimes referred to as reproducibility

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4
Q

formula using a dry solute & a solvent

A

g solute needed = g/mole x mole/L x Liter

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5
Q

units of measurement - m

A
deci  = 0.1
centi = 0.01
milli (m) = 0.001
micro (u) = one millionth 0.0001
nano (n) = one billionth 10-9
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6
Q

parallel dilutions

A

making different dilutions of different concentrations with no relationship to each other

C1V1 = C2 V2
nearly always solve for V1

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7
Q

serial dilutions

A
  • using a dilute solution to an even more dilute solution
  • making several dilutions where there is a constant dilution factor
  • OR where diluted solution is much, much less concentrated than the stock

V1 + V2
________ = dilution factor
V1

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8
Q

spectrophotometer

A

will register:
1. transmittance - light passing thru the sample (ex. 630 nm)
OR
2. absorbance - like absorbed by the sample (range 0.00 - 1.99)

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9
Q

independent variables

A
  • those the scientist chooses (concentration of potassium; dosage of Rx, etc)
  • plotted on x-axis
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10
Q

dependent variable

A
  • results of the experiment
  • dependent on the experiment
  • plotted on y-axis
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11
Q

pH

A

percentage of H+ and OH- ions

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12
Q

acid

A

proton donor

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13
Q

base

A

proton acceptor

  • can decrease the [H+] in 2 ways
    1. dissociate to form OH- (H+ decreases b/c they combine w/OH- for form H2O)
    2. combine directly w/H+ ions (e.g. NH3 combines w/H+ to form NH4
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14
Q

buffers

A
  • release or mine H+ in order to keep a (relatively) constant pH; not keep it neutral
  • most consist of a weak acid (release H+) and a weak base (bind to H+))
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15
Q

why is it important to keep pH stable?

A
  • most biochemical processes proceed normally only when pH stays w/in a fairly narrow range
  • excess of H+ or OH- can interfere w/structure and activity of many biomolecules, esp. proteins (e.g. human blood)

3 buffer systems in body

  1. bicarbonate buffer system
  2. phosphate buffer system
  3. protein buffer system
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16
Q

buffering range

A
  • pH range where buffer is effective to maintain pH even the adding acid or base
  • beyond its range, can no longer stabilize pH
  • can have more than one range
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17
Q

buffering capacity

A
  • ability of buffer to resist changes in pH when acid or base is added
18
Q

Brightfieqld microscopes

A
  • a compound microscope

- magnify & provide resolution

19
Q

prokaryotic cells

A
  • has a cell wall
  • no nucleus
  • no endomembrane system
    e. g. bacteria
20
Q

eukaryotic cells

A
  • nucleus & organelles
  • much bigger than prokaryotic cells
  • no cell wall
    4 main groups:
    1. protists - mostly unicellular
    2. plants
    3. fungi
    4. animals
21
Q

similarities between prokaryotic and eukaryotic cells

A
Both have:
1.  plasma membrane
2.  ribosomes
3, cytosol
4. DNA
22
Q

what affects diffusion rate

A

3 factors

  1. size of molecule
  2. temperature
    - heated = faster diffusion
    - gas move faster than liquid
    - liquid moves faster than solid
  3. medium through which they are moving
23
Q

simple diffusion

- non polar molecules that will diffuse thru plasma membrane

A

oxygen
carbon dioxide
lipids

24
Q

facilitated diffusion

A
  • molecules still go down the concentration gradient, but membrane proteins regulate coming and going
25
Q

molecules that require facilitated diffusion

A

polar molecules, such as:

  • water
  • amino acids
  • simple sugars
  • ions
26
Q

active transport

A
  • goes against the concentration gradient
  • requires ATP
    ex. Na+-K+ pump
27
Q

enzymes

A
  • proteins that speed up reactions by binding to substrates
28
Q

what affects enzymes?

A

temperature
pH
substrate concentration

29
Q

enzyme assay

A

technique to visualize activity of an enzyme

30
Q

thin layer chromatography

A

technique for separating mixture of molecules

31
Q

mobile phase of TLC

A

the moving substance

32
Q

stationary phase of TLC

A

the TLC plate

33
Q

how does TLC work?

A
  • solvent flows up the place
  • most soluble molecules move along the fastest
  • least soluble molecules are left behind as bands on TLC plate
34
Q

how do you differentiate the pigments using the spectrophotometer?

A

the Spec 20 is used to determine the wavelengths at which pigments absorb light.
- some colors may absorb light at more than one wavelength

35
Q

green fluorescent protein (GFP)

A
  • produced by sea jelly Aequorea victoria
  • light is activated by UV light
  • made of 238 amino acids
  • used as a molecular marker
  • can be inserted into DNA vectors so they replicate in E. Coli
36
Q

blue fluorescent protein (BFP)

A
  • not naturally occurring
  • was created by altering the nucleotide sequence of GFP gene
  • only 2 amino acids were changed
  • emits a blue fluorescence instead of green
37
Q

column chromatography

A

isolates specific proteins from a mixture of proteins and other molecules

38
Q

fractions

A

the separated molecules that are collected

39
Q

Sephadex

A
  • polysaccharide beads used to separate proteins
  • pores in the beads separate proteins by size
  • small proteins pass thru the pores, so go slower
  • larger proteins go around the beads, so go faster
40
Q

electrophoresis

A
  • placing molecules in a porous matrix and applying an electric field to move them thru the matrix
  • separates molecules according to their size, shape and charge
41
Q

polyacrylamide gel

A
  • smaller and negatively charged proteins will travel further down the gel, but globular will not travel as far as linear ones (even if same size and similar charge)
  • that is why proteins are denatured before