BSCI 171 - Lab Practical

How to find the concentration of pNP (from measured absorbance)?

Absorbance/extinction coefficient (Beer’s Law)

How to find the AMOUNT of pNP?

concentration of pNP X total volume of sample

How to find the rate of pNP formation?

Amount of pNP/incubation time

How to calculate working solution in a fold problem

If its a fold dilution, divide stock solution by fold to get working solution

mM

10^-3

uM

10^-6

What is the extinction coefficient in a linear equation of absorbance as a function of concentration?

The slope

Ex: y = 22.4x + 0.031

• extinction coefficient is 22.4 M^-1cm^-1

How to read a P20 micropipette?

• 0 - tens

• 1 - ones

• 7 - tenths

17 uL

2-18 uL

• 1

• 3

• 2

13.2 uL

How to read a P200 micropipette?

• 1 - hundreds

• 7 - tenths

• 0 - ones

170 uL

20 - 195 uL

• 0

• 8

• 0

80 uL

How to read a P1000 micropipette?

• 0 - hundredths

• 1 - tenths

• 7 - units

170 uL

150-900 uL

• 9

• 0

• 0

900 uL

What should you do before putting a cuvette into the spectrophotometer?

Blank it, wipe your blank, close the lid, and press 0 to calibrate the machine to zero absorbance.