the final days

Question 1

Tell me something about accuracy/precision and random/systematic error.

Answer 1

AS PER.

Accuracy is more affected by systematic error. Precision is more affected by random error.

Question 2

H-H equation:

Answer 2

pH = pKa + log [base]/[acid]
pH = pKa + log [A-]/[HA]

Question 3

pH equation:

Answer 3

pH = -log[H+]

Question 4

pI equation:

Answer 4

pI = (pK1 - pK2) / 2

on a graph, the pKs are the flat parts surrounding the zero-charge part.

Question 5

Checking the H-H equation:

Answer 5

When pH is less than pKa, more acid

Question 6

Absorbance equation:

Answer 6

A = log (1/T)

Question 7

Beer-Lambert equation:

Answer 7

A = elc

Question 8

Bradford assay:

Answer 8

Coomassie binds AAs. Unbound dye is 465 nm, bound dye is 595 nm. Absorbance varies with protein shape, AA composition/pH. Upper limit of 1 mg/mL. Fast.

Question 9

Biuret assay:

Answer 9

Copper sulfate (CuSO4) interacts with peptide bonds in alkaline conditions. Bound dye is 540 nm. Upper limit of 10 mg/mL. Slow.

Question 10

Resolution equation:

Answer 10

R = 0.61 λ / NA
NA = n sin θ
θ = 1/2 angle that light enters

Question 11

Absorbance wavelengths of: bacteria, DNA, RNA, proteins

Answer 11

Bacteria: 595-600 nm
DNA and RNA: 260 nm
Proteins: 280 nm

Question 12

Equation for DNA concentration:

Answer 12

abs * dilution factor * 50 = [DNA] in ug/mL

Question 13

Gram stain:

Answer 13

CV. Iodine. Alcohol. Safranin.
+ purple
- pink

Question 14

Acid-fast stain:

Answer 14

Carbol-fuschin. Acid. Meth blue.
+ red
- blue

Question 15

Negative stain:

Answer 15

Nigrosin (or other big negative dye). Maybe CV.

To visualize glycocalyx.

Question 16

Leifson stain:

Answer 16

CV. Mordant (phenol, tannic acid).

To visualize flagella.

Question 17

Endospore stain:

Answer 17

Malachite green. Safranin.
+ green
- red

Question 18

Macconkey agar:

Answer 18

Select for gram neg. Differential for lactose fermentation (purple).

Question 19

MSA plate:

Answer 19

Mannitol salt agar. Select for halophiles. Differential for mannitol fermentation (yellow).

Question 20

Blood agar:

Answer 20

Differential for hemolysin activity (alpha, beta, gamma).

Question 21

Saboraud dextrose agar:

Answer 21

Select for high sugar and pH.

Question 22

SIM deep:

Answer 22

Differential for:
Sulfur reduction. + black.
Indole production. + red (with Kovak).
Motility.

Question 23

Oxidase test:

Answer 23

Cytochrome 3 oxidase. + purple.

Question 24

Catalase test:

Answer 24

Differentiate staphcocc and strepcocc. + staph, - strep.

Question 25

CFU plating equation:

Answer 25

(cfu/mL)/desired count * volume plated = 1/dilution factor

Question 26

Reaction rate equation:

Answer 26

v = - Δ[S] / Δt 
v = + Δ[P] / Δt

Question 27

M-M equation:

Answer 27

v0 = [S] * Vmax / [S] + Km

Question 28

Km:

Answer 28

Km = [S] when V0 = 1/2 Vmax

Question 29

Turnover number equation:

Answer 29

kcat = Vmax / [E]t

Question 30

1 Unit of enzyme activity:

Answer 30

Can catalyze 1 umol in 1 minute

Question 31

Activity:

Answer 31

U / mL or U / uL

Question 32

Specific activity:

Answer 32

Activity / [protein], in U / mg or U / ug

Question 33

Yield vs purity of purification:

Answer 33

Yield - compares activity before/after

Purity - compares specific activity before/after

Question 34

Partition coefficient:

Answer 34

Kav = (Ve - Vo) / (Vt - Vo)

Question 35

PCR equation:

Answer 35

# of copies = (2^n - 2*n) * x
x = # you started out with

Question 36

Melting temp (PCR):

Answer 36

Tm = 2ºC (A+T) + 4ºC (G+C)