Question

1) You have two unknown, unlabeled clear solutions. One is DNA and the other is protein. How do you determine which solution is DNA, which one is protein

2)In an SDS gel larger proteins travel ________________(longer/shorter) distance compared to smaller proteins.

3) Assuming that the isolation and purification of Rubisco went as expected, which fraction isolated should have the highest concentration of pure Rubisco? Please explain. (There was a total of 11 fractions)

4) Your first task as a graduate student researcher was to have isolated and purify 7 different proteins from various sources. One of these proteins that you have isolated was Rubisco. Unfortunately, you did not label which tubes contained Rubisco. State the experiment(s) that can be done to ensure the identity of Rubisco.

Answer 1

1) by using UV-Spectrometry analysis, we can determine the type of sample. All we have to do is scan both the unlabeled sample between the wavelength of 200nm to 300nm and read the pick. If the sample will have DNA it will give a peak at 260nm wavelength will protein will give a pick at 280nm wavelength.

2)In an SDS gel, larger proteins travel shorter distance compared to smaller proteins.

3) the highest concentration of Rubisco will be nearly in somewhere fraction number 4 to 8 as initial fraction will contain the smaller size protein or other free salt molecules having higher Rf value, therefore, move faster than Rubisco and fractionate first.

4) rubisco can be identified from the unlabeled tube by Western blotting technique, using anti- Rubisco antibodies.