cell bio homework 3
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 acrylamide refers to the size of the pores as percent acrylamide increases the size of the pores decreases.
2. Describe the purpose of each loading buffer ingredient added to protein samples for SDS-PAGE analysis (hint- there are 4 ingredients).
3. You purified protein X via affinity chromatography (no diafiltration step performed) and ran an SDS-PAGE gel of the sample with a set of controls. Below is the result of your SDS-PAGE analysis.
1 2 3 4 Figure 1. SDS-PAGE of purified protein X. Lane 1, Protein ladder (in Daltons). Lane 2, purified protein X (affinity chromatography). Lane 3, purified protein X (company manufactured). Lane 4, elution buffer.
a. What is the benefit of a protein ladder/molecular weight marker in an SDS-PAGE gel? Describe what you can learn about the protein bands found in lanes 2, 3 and 4 based on the protein ladder bands. The benefit of protein ladder is to have a point of reference for the molecular weight found in the wells next to it. I found that well 2 contained the proteins found in both well 3 and well 4 because it matched up with the bands for each of them. So well 2 evidently has 2 proteins thus 2 bands. Well 3 has one protein 1 band but with a high concentration. Well
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 acrylamide refers to the size of the pores as percent acrylamide increases the size of the pores decreases.
2. Describe the purpose of each loading buffer ingredient added to protein samples for SDS-PAGE analysis (hint- there are 4 ingredients).
3. You purified protein X via affinity chromatography (no diafiltration step performed) and ran an SDS-PAGE gel of the sample with a set of controls. Below is the result of your SDS-PAGE analysis.
1 2 3 4 Figure 1. SDS-PAGE of purified protein X. Lane 1, Protein ladder (in Daltons). Lane 2, purified protein X (affinity chromatography). Lane 3, purified protein X (company manufactured). Lane 4, elution buffer.
a. What is the benefit of a protein ladder/molecular weight marker in an SDS-PAGE gel? Describe what you can learn about the protein bands found in lanes 2, 3 and 4 based on the protein ladder bands. The benefit of protein ladder is to have a point of reference for the molecular weight found in the wells next to it. I found that well 2 contained the proteins found in both well 3 and well 4 because it matched up with the bands for each of them. So well 2 evidently has 2 proteins thus 2 bands. Well 3 has one protein 1 band but with a high concentration. Well