Biochemistry Lab Practical

Question 1

What is accuracy and precision?

Answer 1

Accuracy indicated how close a measurement is to the true value.

Precision is how repeatable a result for the same measurement.

Question 2

If 180 µL sample is needed, which micropipette do you prefer for higher accuracy? P-1000 or P-200? *

Answer 2

P-200 because it is more accurate

Question 3

What is the function of a buffer?

Answer 3

Prevents pH changes.

Question 4

What is the pH of our blood?

Answer 4

7.4

Question 5

What is the unit of A in the Beer-Lambert law?

Answer 5

Absorbance

Question 6

What are the four advantages of Bradford assay for figuring out protein concentration?

Answer 6

Fast, affordable, stable, and sensitive.

Question 7

How to do a dilution to achieve dilution factor = 4?

Divide final volume/ 4

Answer 7

1 to 4 dilution. One part of the original solution is diluted into total of 4 parts.

Question 8

Which protein samples is used to obtain a standard curve?

Answer 8

Bovine Serum Albumin (BSA)

Question 9

What is the function of a standard curve?

Answer 9

Helps to determine the concentration of the unknown.

Question 10

Why is it necessary to collect the baseline without adding enzyme?

Answer 10

To have something to compare it. The Ko

Question 11

Why is it necessary to collect the baseline without adding enzyme?

Answer 11

To have something to compare it. The Ko

Question 12

What is the function of ammonium persulfate?

Answer 12

Creates free radicals and initiates chain reactions .

Question 13

What is the function of SDS?

Answer 13

Sodium dodecyl sulfate is a detergent that denatures protein.

Question 14

What is the function of DTT or beta mercaptoenthanol?

Answer 14

Is a reducing agent to break disulfide bonds between two Cystine residues.

Question 15

What is the pH of the buffer to make the separating and stacking gel?

Answer 15

Stacking gel pH 6.8

Separating/Resolving Gel pH8.8

Question 16

Does larger or smaller peptide migrate faster in SDS Page?

Answer 16

The smaller peptide

Question 17

What is the function of the DNA marker or ladder?

Answer 17

Serves as a standard sized DNA molecules.

Question 18

Can we use 1000V to run the electrophoresis? Why/why not?

Answer 18

No. Because it can melt the gel and lower the resolution.

Question 19

What is the function of low and high concentrations of imidazole in the buffers?

Answer 19

Low concentration is the wash buffer.

The high concentration s the elution buffer.

Question 20

Why does the histidine tag bind to the Ni column?

Answer 20

The lone pair electrons on histidine bind to the Ni2+ on the column.

Question 21

Why should we not vortex samples in plasmid purification?

Answer 21

It can shear chromosomal DNA.

Question 22

What is a restriction enzyme?

Answer 22

It cleaves DNA at a specific sequence.

Question 23

Write a palindromic sequence with 6 nucleotides.

Answer 23

5-GAATTC-3’

3-CTTAAG-5’

Question 24

Given the pKa of CAPS is 10.4 what is a good buffer range system?

Answer 24

pH 9.7-11.1

Question 25

In the lab, what are the two substrates and products of the reaction catalyzed by LDH?

Answer 25

Substrate= Pyruvate and NADH
Products= Lactate and NAD+