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Flashcards in 4.1-5.17 Deck (42)
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1
Q

kind of independent variables

A

MANIPULATED

  • age
  • sex
  • race
  • SES
  • standardized measures and scores
2
Q

4 sampling biases

A

a NOT random sample. types of bias include

  1. special real area - people are selected in a physical space (the quad - this is not representative of all the students)
  2. self-selection bias - participant choose to participate
  3. advertising - only the advertised people
  4. healthy user bias - picking only healthy subjects (say, people who use the gym)
3
Q

standard error

A

standard deviation / (sample size)^(1/2)

4
Q

test-retest reliability

A

taking the MCAT multiple times should result in equivalent scores

5
Q

inter-rater reliability

A

the degree to which two researchers or raters agree in; two doctors come up with the same diagnosis

6
Q

validity

A

how well an experiment measures what it is trying to measure

7
Q

internal validity

A

demonstrate a causal relationship between two variables (highly controlled), avoid confounding factors

8
Q

external validity

A

results of study can be generalized to other situations and other people

9
Q

construct validity

A

does the survey ask the question clearly?

10
Q

liquid-liquid extraction

A

like dissolves like

organic compound is extracted with water; inorganic salts, acids/bases, and polar low-molecular weight compounds (alcohols, amines, carboxylic acids)

11
Q

acid extraction

A

basic (amines) can be extracted from mixtures of organic compounds upon treatment by an acid

formation of a positively charged ion (cation), soluble in AQUEOUS solution and removed from organic compounds that remain dissolved in the organic phase

12
Q

base extraction

A

converts carboxylic acids into anionic salt -> found in aqueous layer

NaHCO3 cannot extract phenols, but NaCl can

convert the acid into a SALT, which can be extracted away

13
Q

chromatography

A

SEPARATE MIXTURES

“Chromatography involves the SEPARATION of colors”

14
Q

thin layer chromatography (TLC)

A

“The polar ice caps are dangerously thin layered”

POLARITIES

more polar -> travels SLOWER (POLAR STATIONARY PHASE)

less polar -> travels FASTER

Rf = ratio (1/1 is extremely not polar)

good for small amounts

thin layer of absorbant (silica, SiO2) = POLAR STATIONARY PHASE

15
Q

column (flash) chromatography

A

POLARITY - good for BULK

pour down a column, SiO2 slows down the polar, so you capture the non-polar first

16
Q

Ion exchange chromatography

A

VARIOUS CHARGES

MIXTURES OF PROTEINS

a resin (anionic sulfate groups) captures positive charges, the negative and neutral charged particles are eluted first. Later, the positive charged species can be eluted afterward with sodium-containing solution

CATION exchange resin -> positively charged proteins with pI greater than pH elute elute SLOWLY (CATION exchange KEEPS positively charged) -> proteins with pI below pH pass through

anion exchange -> hold on to low pI, while high pI (positive charged) elute first

17
Q

High performance liquid chromatography

A

reverse phase HPLC:

opposite of TLC; more polar compounds elute first (stationary phase is silica gel bonded to a non-polar group = NONPOLAR STATIONARY PHASE)

Mobile phase = POLAR

18
Q

size exclusion chromatography

A

MOLECULAR SIZE

POROUS BEADS

BIG = FAST

19
Q

affinity chromatography

A

PURIFY PROTEINS/macromolecules

Target is TRAPPED in the STATIONARY PHASE

ANTIGEN/ANTIBODY

Enzyme/Subtrate

Receptor/Ligand

Protein/Nucleic acid

trapping in a stationary phase, washing to remove unwanted components; target protein is released off the solid phase

affinity tags = His tags

20
Q

Gas chromatography

A

DIFFERENT VOLATILITIES

MORE VOLATILE = carried away FASTER

21
Q

distillation

A

raise temperature, overcome intermolecular forces, vapor is collected and condensed

SIMPLE -> salt water is boiled, removing the salt

22
Q

Fractional distillation

A

when difference in boiling points is not large

remove something of a lower boiling point

23
Q

spectroscopy (light)

A

SEEING structural features based on absorption patterns; light excites the molecules, energy is released

24
Q

Mass spectroscopy

A

determines the MASS of compounds in a sample

ionized in a high vacuum, bombarded by high energy ELECTRONS, magnetic field, flight path of charged species alters

25
Q

UV/VISIBLE light spectroscopy

A

conjugated systems = wavelength of maximum absorption increases

if a compound absorbs UV, all visible wavelengths will be reflected (white)

if a compound absorbs BLUE light, it is will appear ORANGE

MEMORIZE THIS:
RED - GREEN (725 nm - 525 nm)
Orange - blue (625 nm - 460 nm)
Yellow - violet (580 nm - 415 nm)

MORE CONJUGATED = ABSORBS LOWER FREQUENCY = more likely blue/violet

26
Q

infrared spectroscopy (identify functional groups)

A

IR == STRETCH (“I REALLY need to STRETCH”)

IR (2.5 - 20 micrometers) can excite organic molecules

Wavenumber = 1/wavelength = 1/c * v (measured in reciprocal centimeters)

MEMORIZE THE STRETCH FREQUENCIES (p. 64)

carbonyl = 1700 cm-1
Alkene = 1650
triple bond = 2260-2100
hydroxyl -> 3600-3200

C-H for sp3 = 3000-2850
C-H for sp2 = 3150-3000
C-H for sp = 3300

27
Q

NMR Spectroscopy (proton NMR)

A

look at unique hydrogens (group them)

peaks is number of neighboring hydrogens + 1

area is the number of protons (the integration)

if EN atom is in close proximity, decreases electron density and DESHIELD it, DOWNfield shift (goes LEFT)

AROMATIC proton = 6.5-8 ppm shift
ALKENE = 5-6 ppm shift

attached to O, N are DESHIELDED (2-5 ppm)
carboxylic acid = 10-13 ppm
alcohol = 2-5 ppm
ALKYL = 0-2 ppm

28
Q

ELISA*

A

enzyme-linked antibodies

determines PRESENCE of ANTIGENS/PROTEINS/CYTOKINES/ANTIBODIES

LOOK AT PICTURE

“Enzyme-linked ANTIBODY” is the DETECTION enzyme, which leads to COLOR CHANGE

29
Q

radioimmunoassay (RIA)*

A

measures RADIOACTIVITY in immune complexes via RADIOLABELED ANTIBODIES

measure radioactivity

determine amount of HORMONES or drugs

30
Q

electrophoresis*

A

SEPARATION based on SIZE or CHARGE

acrylamide and agarose (GEL) form “nets” as they solidify

DNA is negatively charged

SMALL moves FASTER

NEGATIVE move FASTER

31
Q

Southern blotting

A

blotting = transfer of DNA/proteins from electrophoresis to nitrocellulose

SPECIFIC SEQUENCES within a heterogenous sample of DNA -> isolate and purify target DNA sequences

filter is PROBED with radiolabeled NUCLEOTIDES that are complementary to portion of target DNA -> allows visualization

  1. Cleave DNA (endonuclease)
  2. Run on gel electrophoresis
  3. Add filter
32
Q

Northern blotting

A

RNA is separated via gel electrophoresis, rather than DNA

determines if GENE PRODUCTS are being expressed

33
Q

Western blotting

A

presence of certain PROTEINS, DIAGNOSTIC TOOL

an enzyme FLOURESCES when detecting a substrate, brightness is proportional to abundance

Use of PRIMARY/SECONDARY ANTIBODIES instead of nucleotides

34
Q

restriction endonuclease

A

bacterial enzyme

RESTRICT the reproduction of hostile viruses

CUTS in the MIDDLE of DNA chain (exo cuts on the ends)

STICKY END is GOOD

35
Q

plasmid

A

can have a gene for antibiotic resistance, and incorporate a gene of interest, and can survive while the other bacteria die

36
Q

heating DNA can separate the strands

A

primers bond, then DNA pol adds nucleotides to the 3’ end

37
Q

DNA fingerprinting depends on …

A

POLYMORPHISMS = 2-100 base pair stretches of repetitive DNA

  1. Restriction Fragment Length Polymorphism (10-100 base pairs) - RESTRICTION ENDONUCLEASE followed by GEL ELECTROPHORESIS
  2. Short tandem repeats - DNA obtained, PCR’d, and repetitive DNA in introns is analyzed via SOUTHERN BLOTTING
38
Q

knocking down gene expression with …

A

RNA interference

  • microRNA
  • small interfering RNA

degrade mRNA

39
Q

ddNTPs

A

dideoxynucleotide triphosphate
lack the 3’ hydroxyl group, cannot elogate

important for DNA sequencing (Sanger)

40
Q

immunohistochemistry

A

specific for protein expression

41
Q

Bradford Quantification

A

protein quantification

proteins bind to blue pigment

42
Q

dna sequencing

A

ddNTPs