Exam 1: Intro to Lab Skills

Question 1

SI (units)

Answer 1

The Systeme International D-Unites (SI) is internationally agreed upon system of measurements, using the meter, kilogram, and second as the fundamental units for measurement of length, mass and time

Question 2

SI- Length

Answer 2

measured quantitiy - length
SI unit - meter
Symbol - m

Question 3

SI - Mass

Answer 3

measured quantity - mass
SI unit - kilogram
symbol - kg

Question 4

SI - Amount of substance

Answer 4

measured quantity - amount of substance
SI unit - mole
symbol -mol

Question 5

SI - Time

Answer 5

measured quantity - time
SI unit - second
symbol - s

Question 6

SI -Temperature

Answer 6

measured quantity- temperature
SI unit - kelvin
symbol - K

Question 7

Convert milliliters to micro-liters, reverse

Answer 7

Think of base as liters

milli - 10^-3, 1000 mililiters in 1 liter

micro- 10^-6, 1 million micro-liters in 1 liter
(1000 micro-liters in milliliter)

Question 8

Know what the following lab equipment looks like

Answer 8

Scale, conicle, and cuvette

Question 9

Coosmassie G-250

Answer 9

a dye, binds to the R groups of the protein and the color changes to blue

a stronger blue color indicates stronger concentration of protein

Question 10

spectrophotometer

Answer 10

generates light of specific wavelength, measures the absorption of light in a sample in a defined container (a cuvette)

Question 11

Bradford Assay Procedure

Answer 11

-a method for quantitative analysis of a protein, necessary before futher processing such as isolation, separation, and analysis of proteins by electrophoresis

Question 12

Four main steps of Bradford Assay procedure

Answer 12

• prepare dilution series of known protein standards and preparation of unknowns
• addition of bradford dye and incubate for 5-60 minutes
• bind of dye to protein,resultin in color change to blue and produces quantitative reading of absorption at A595 on spectro.
• standard curve to determine unknown protein conccentration

Question 13

Why are visual comparisons important in Bradford Assay?

Answer 13

Comparing colors of unknown samples to known samples can give a closer estimate of the unknown protein sample’s concentration

Question 14

spectrophotometer

Answer 14

• generates light of specific wavelength
  -measures absorption of light in a sample in defined container (cuvette!!)

Question 14

Beer-Lambert Law/Beer’s Law

Answer 14

linear relationship between absorbance and concentration of an absorbing species

Question 15

What is the principle behind Bradford Assay?

Answer 15

It provides simplicitiy for a conclusion to an experiment (also qualitative measurement by the eye or quantitatively by spectrophotometer). It will provide a correlation between the amount of blue color and the amount of proteins in the sample (more proteins, more intense blue).

Question 16

Steps of a Dilution Series Simplified

Answer 16

• prepare a dilution of milk samples
  -prepare protein standars and unkown protein samples for assay
  -visually compare colors of sample A and sample B with known concentrations (to estimate concentration qualitatively)
• measure cuvettes in spectrophotometer
• generate standard curve and calculate concentration of sample protein A and B