QBM exam 2| Questions Solved with
Verified Correct Answers | Latest Update
2024-2025
What would you expect absorbance of a sample to be if it had a transmittance of 71.28%
- ANSWER 0.147
A DNA sample with an A_260 of 1.92 and an A_280 of 1.35 is sufficiently pure. - ANSWER False
What region of an enzyme is often found to be highly conserved at the amino acid level
across different species? - ANSWER Active site
Which of the following is correct regarding enzymes? - ANSWER Enzymes can increase the
rate of a reaction, but do not shift the equilibrium of a reation.
Which wavelength would you use to measure protein concentration directly (without any
chromagenic assay)? - ANSWER 280
Alligning the tertiary structures of chymotrypsin and subtilisin illustrates - ANSWER convergent
evolution
How would you prepare 25 ml of a 200 mM solution of HEPES (M_w = 238g/mol) pH 7.5? -
ANSWER Add 1.19 grams HEPES to approx 20 ml of water, pH to 7.5, bring up to 25 ml.
75 M is equivalent to - ANSWER 75 moles per liter
, An 8-ounce cup of coffee contains approximately 95 mg of caffeine (M_w= 194g/mol). What is
the molarity of caffeine in a cup of coffee in millimolar? Note: 1 ounce=30ml - ANSWER 2.04
mM
You wish to perform an ammonium sulfate (M_w=132) cut, and need 10ml each of 10%,
20%, 30%, and 40% w/v ammonium sulfate (so 40 ml total). How many total grams of
ammonium sulfate do you need to prepare these four solutions? - ANSWER 10 g
How do you prepare 260 ml of 60% v/v of ethanol? - ANSWER
Add156mlofethanoltoabeaker,bringupto260mlwithdH2O
In 1 cup of whole milkthere are 124 IUs of vitamin D (M_w= 384 g/mol); for vitamin D, 1 IU=
0.025 micrograms. What is the concentration of vitamin D in 1 cup of whole milk in
nanomolar? Note: 1cup=236ml - ANSWER 34.20 nM
28 ng/ul is equivalent to which of the following? - ANSWER 28 ug/ml
The concentration of hemoglobin (17 kDa) in a patient suffering from sickle cell anemiea is
approximately 7 grams per deciliter of hemoglobin in this patient in millimolar? - ANSWER 4.11
mM
An experiment calls for 40 ul of the GST enzyme at a concentration of 2000 units/ul. If you
have a stock solution of the enzyme at 65,000 units/ul, how many microliters of the stock are
required? - ANSWER 1.2 ul
How do you prepare 450 ml of 3 M HCL from a 7 M stock of HCL? - ANSWER Add 193 ml of
the 7 M stock to a beaker, bring up to 450 ml with dH2O
To conduct research and receive a grant for project involving human subjects, the
researchers must first obtain approval from the - ANSWER IRB
Verified Correct Answers | Latest Update
2024-2025
What would you expect absorbance of a sample to be if it had a transmittance of 71.28%
- ANSWER 0.147
A DNA sample with an A_260 of 1.92 and an A_280 of 1.35 is sufficiently pure. - ANSWER False
What region of an enzyme is often found to be highly conserved at the amino acid level
across different species? - ANSWER Active site
Which of the following is correct regarding enzymes? - ANSWER Enzymes can increase the
rate of a reaction, but do not shift the equilibrium of a reation.
Which wavelength would you use to measure protein concentration directly (without any
chromagenic assay)? - ANSWER 280
Alligning the tertiary structures of chymotrypsin and subtilisin illustrates - ANSWER convergent
evolution
How would you prepare 25 ml of a 200 mM solution of HEPES (M_w = 238g/mol) pH 7.5? -
ANSWER Add 1.19 grams HEPES to approx 20 ml of water, pH to 7.5, bring up to 25 ml.
75 M is equivalent to - ANSWER 75 moles per liter
, An 8-ounce cup of coffee contains approximately 95 mg of caffeine (M_w= 194g/mol). What is
the molarity of caffeine in a cup of coffee in millimolar? Note: 1 ounce=30ml - ANSWER 2.04
mM
You wish to perform an ammonium sulfate (M_w=132) cut, and need 10ml each of 10%,
20%, 30%, and 40% w/v ammonium sulfate (so 40 ml total). How many total grams of
ammonium sulfate do you need to prepare these four solutions? - ANSWER 10 g
How do you prepare 260 ml of 60% v/v of ethanol? - ANSWER
Add156mlofethanoltoabeaker,bringupto260mlwithdH2O
In 1 cup of whole milkthere are 124 IUs of vitamin D (M_w= 384 g/mol); for vitamin D, 1 IU=
0.025 micrograms. What is the concentration of vitamin D in 1 cup of whole milk in
nanomolar? Note: 1cup=236ml - ANSWER 34.20 nM
28 ng/ul is equivalent to which of the following? - ANSWER 28 ug/ml
The concentration of hemoglobin (17 kDa) in a patient suffering from sickle cell anemiea is
approximately 7 grams per deciliter of hemoglobin in this patient in millimolar? - ANSWER 4.11
mM
An experiment calls for 40 ul of the GST enzyme at a concentration of 2000 units/ul. If you
have a stock solution of the enzyme at 65,000 units/ul, how many microliters of the stock are
required? - ANSWER 1.2 ul
How do you prepare 450 ml of 3 M HCL from a 7 M stock of HCL? - ANSWER Add 193 ml of
the 7 M stock to a beaker, bring up to 450 ml with dH2O
To conduct research and receive a grant for project involving human subjects, the
researchers must first obtain approval from the - ANSWER IRB
