Biochemistry Lab Practical Flashcards
What is accuracy and precision?
Accuracy indicated how close a measurement is to the true value.
Precision is how repeatable a result for the same measurement.
If 180 µL sample is needed, which micropipette do you prefer for higher accuracy? P-1000 or P-200? *
P-200 because it is more accurate
What is the function of a buffer?
Prevents pH changes.
What is the pH of our blood?
7.4
What is the unit of A in the Beer-Lambert law?
Absorbance
What are the four advantages of Bradford assay for figuring out protein concentration?
Fast, affordable, stable, and sensitive.
How to do a dilution to achieve dilution factor = 4?
Divide final volume/ 4
1 to 4 dilution. One part of the original solution is diluted into total of 4 parts.
Which protein samples is used to obtain a standard curve?
Bovine Serum Albumin (BSA)
What is the function of a standard curve?
Helps to determine the concentration of the unknown.
Why is it necessary to collect the baseline without adding enzyme?
To have something to compare it. The Ko
Why is it necessary to collect the baseline without adding enzyme?
To have something to compare it. The Ko
What is the function of ammonium persulfate?
Creates free radicals and initiates chain reactions .
What is the function of SDS?
Sodium dodecyl sulfate is a detergent that denatures protein.
What is the function of DTT or beta mercaptoenthanol?
Is a reducing agent to break disulfide bonds between two Cystine residues.
What is the pH of the buffer to make the separating and stacking gel?
Stacking gel pH 6.8
Separating/Resolving Gel pH8.8
Does larger or smaller peptide migrate faster in SDS Page?
The smaller peptide
What is the function of the DNA marker or ladder?
Serves as a standard sized DNA molecules.
Can we use 1000V to run the electrophoresis? Why/why not?
No. Because it can melt the gel and lower the resolution.
What is the function of low and high concentrations of imidazole in the buffers?
Low concentration is the wash buffer.
The high concentration s the elution buffer.
Why does the histidine tag bind to the Ni column?
The lone pair electrons on histidine bind to the Ni2+ on the column.
Why should we not vortex samples in plasmid purification?
It can shear chromosomal DNA.
What is a restriction enzyme?
It cleaves DNA at a specific sequence.
Write a palindromic sequence with 6 nucleotides.
5-GAATTC-3’
3-CTTAAG-5’
Given the pKa of CAPS is 10.4 what is a good buffer range system?
pH 9.7-11.1
In the lab, what are the two substrates and products of the reaction catalyzed by LDH?
Substrate= Pyruvate and NADH Products= Lactate and NAD+
