Essay on cell bio homework 3

940 Words Nov 16th, 2013 4 Pages
Cellular Biology Lab – Homework #3
Due the week of Nov. 4th
You may use the lab manual, pre-lab lectures, and credible internet resources, however you may not use your cell bio lab classmates as a resource. You will most likely see this material again on the Final and I highly encourage you to work individually and seek help from myself or your TA. Plagiarism will result in an automatic zero.

1. In the cell bio lab, we use company manufactured gels, however you can make you own polyacrylamide gels. List all of the ingredients found in an SDS-PAGE gel. Which ingredients are responsible for polymerizing the solution? How does the percentage of acrylamide effect the migration of proteins (ex: 4% gel vs. 18% gel)?
The percent
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Rf= distance traveled by protein / total distance traveled

4. In lab 9, we will use differential centrifugation to separate cauliflower cell organelles into individual fractions. Describe the basic principles of differential centrifugation. Discuss why a relatively low speed centrifuge spin is enough to separate nuclei from a cell lysate while chloroplasts and lysosomes require higher speeds to separate. Relatively Low speed centrifuge spin is enough to separate nuclei from a cell lysate because the molecular weight difference of nuclei and the cell lysate is very large. Higher Centrifuge speeds are required to separate chloroplasts and lysosomes because they have a small difference in molecular weight.

5. You need to prepare 200 uL of each protein at a concentration of 1mg/mL for an upcoming experiment. Calculate the recipe to make each desired solution at the above concentration and volume. Do you have enough materials to make each dilution? Note: You diluent is water.

a. Alpha-tubulin: you have 500 uL at 5 mg/mL
a.i. (V1)(5 mg/mL)=(200uL)( 1mg/mL ) = 40 uL of stock Alpha-tubulin solution and 160 uL of water Has enough stock solution

b. TGFbeta: you have 300 uL at 2.4 mg/mL
b.i. (V1)(2.4 mg/mL)=(200uL)( 1mg/mL )= 83.33 uL of stock TGFbeta solution and 116.67 uL of water Has enough stock solution

c. Albumin: you have 150 uL at 1 mg/mL
c.i. (V1)(1 mg/mL)=(200uL)(

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