1. What is the importance of micropipettes and gel electrophoresis in genetic en
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Question
1. What is the importance of micropipettes and gel electrophoresis in genetic engineering?
2. During the labs, you were often reminded to avoid contact with the pipette tips—for example, you were asked to put the pipette tip on without using your hands, to avoid setting down the micropipette, to use the ejector button to remove the tip, and to keep the tip box closed. If you were working with plasmids and bacterial cells, why would these precautions be important?
3. Study your gel electrophoresis results:
4. Which solution sample contained a single dye: S1, S2, or S3? How do you know?
5. The molecular weights for the dyes are 452.38 atomic units (au) for orange G, 669.98 au for bromophenol blue, and 538.62 au for xylene cyanole. How do these weights compare with your original conclusions about the weights of the dyes?
6. Do you think there was a difference in the amount of charge on one of the dye molecules? Explain the reasoning for your response.
Explanation / Answer
1. What is the importance of micropipettes and gel electrophoresis in genetic engineering?
A micropipette is an essential tool for the dispensing of very small quantities of DNA into microtubes. Gel elecrophoresis is used to separate and identify a mixture of different biomolecules including DNA. Gel electrophoresis works by using electricity to push DNA from the negative pole to the positive pole. The wells represent the negative side of the gel. The lightest pieces of DNA will move the farthest, and the heaviest pieces of DNA will move the least. Individuals with stripes in the same places are very likely related individuals. The components of each mixture can then be identified by their location in the gel.
2. During the labs, you were often reminded to avoid contact with the pipette tips—for example, you were asked to put the pipette tip on without using your hands, to avoid setting down the micropipette, to use the ejector button to remove the tip, and to keep the tip box closed. If you were working with plasmids and bacterial cells, why would these precautions be important?
All these precautions are only to avoid cross contamination of samples.
3.Study your gel electrophoresis results:
4. Which solution sample contained a single dye: S1, S2, or S3? How do you know?
The dyes with negative charge are bromophenol blue, orange G and xylene cyanol. So they move towards positive charge. S1 is organge G, is a single dye, with lesser molecular weight as it moves greatest distance in the gel.
When the dyes are loaded in the middle of an agarose gel and current is applied, the molecules migrate according to their charge and size. After a period of exposure to the electrical current, the dye molecules will be separated, their relative positions determined by their mobility through the agarose sieve and their charges.Smaller DNA fragments move through agarose faster than largerDNA molecules.
5. The molecular weights for the dyes are 452.38 atomic units (au) for orange G, 669.98 au for bromophenol blue, and 538.62 au for xylene cyanole. How do these weights compare with your original conclusions about the weights of the dyes?
Orange G is 453 au, Xylene Cyanole and Bromophenol Blue, with molecular weights of 670 daltons and 539 daltons, respectively. When the dyes are loaded in the middle of an agarose gel and current is applied, the molecules migrate according to their charge and size. After a period of exposure to the electrical current, the dye molecules will be separated, their relative positions determined by their mobility through the agarose sieve and their charges. Orange G moves fast towards positive electrode and then Bromophenol Blue migrate toward the positive electrode,and Xylene cyanole comes last.The Orange G is only 50 bp in size and is easily run off the end of the gel. It runs far ahead of the Bromophenol blue which is the easiest dye to see.
6. Do you think there was a difference in the amount of charge on one of the dye molecules? Explain the reasoning for your response.
NO. all the dyes are negatively charged .It could be said by seeing the movement of dyes towards the positive charge.
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