Homework 1 DNA Gel Electrophoresis Buffer Preparation Question 1 Use the followi
ID: 143642 • Letter: H
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Homework 1 DNA Gel Electrophoresis Buffer Preparation Question 1 Use the following information to determine the masses and volumes of each component needed to prepare 2 liters of 50XTAE. You must first prepare a 0.5M stock solution of EDTA (1 liter) before preparing the 50X TAE buffer. This buffer also contains 114.2ml of glacial acetic acid in addition to the Tris and EDTA. Include a statement about any adjustment made for the final volume. 50X TAE DNA Electrophoresis Buffer (2 M Tris, 50 mM EDTA) Tris, MW 121.13 g/mol EDTA, MW 292.25 g/molExplanation / Answer
A. Components required 1.EDTA (MW 292.25 g/mol) :molarity in 50X buffer would have to be 50mM
2. Tris (MW 121.13 g/mol) :molarity in 50X buffer would have to be 2M
3. glacial acetic acid 114.2 ml in 2L of 50X buffer
B. Preparation of 0.5M EDTA stock solution: For 1 liter
1M EDTA solution should have 292.25 grams EDTA in 1 liter solution, therefore 0.5M EDTA solution should have 292.25/2 or 146.125 grams EDTA in 1 liter solution.
# Weigh out 146.125 grams of EDTA
# Dissolve that in 800 milliliter deionized water.
# Top up the solution to a final volume of 1 liter.
# Autoclave the stock solution properly.
C. Preparation of 50X TAE Buffer: 1 liter of 1M Tris solution would contain 121.13 grams Tris, therefore 1 liter of 2M Tris solution should contain 121.13 x 2 or 242.26 grams Tris and 2 liter of 2M Tris solution should contain 242.26 x 2 or 484.52 grams Tris.
# Weigh out 484.52 grams of Tris-base and dissolve in approximately 1400 milliliters of deionized water
# Cautiously add 114.2 milliliters of glacial acetic acid and 200 milliliters of 0.5 M EDTA (from autoclaved EDTA stock solution)
# Finally adjust the solution to a final volume of 2 liter by adding deionized water.
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