Coarse extraction and identification of DNA

tothe crude extraction and identification of DNAthe method of coarse extraction and identification of DNA from theSociety to observe the extracted DNA material.TheofDNA in the sodium chloride solution changes with the concentration of sodium chloride. DNA is the least soluble when the concentration of sodium chloride is 0.14mol/L. Using this principle, DNA dissolved in a solution of sodium chloride can be dissected.
DNA is insoluble in an alcohol solution, but certain substances in cells can be dissolved in an alcohol solution. Using this principle, DNA with less impurities can be further extracted.
DNA is dyed blue when met with dhiphenylamine (boiling water bath), so it can be used as a reagent
DNA
.Instruments and Equipment ) 1. Iron stand 2. Glass rod (1) 3. Filter paper 4. Measuring tube (100ml, 1) 5.
Beech
(100ml 1, 50ml and 500ml 2 each) 6.
Test tube
(20ml, 2)
7.
Funnel
(1) 8. Test tube clip (2)
9. Gauze (15 pieces) 10.
centrifuges
(1)( experimental )1. Chicken blood cell fluid (5 ml to 10 ml) 2. 95% ethanol (pre-cooled 24h) 3. Distilled water 4. Sodium citrate (mass concentration 0.1g/ml) 5. Sodium chloride (2mol/L and 0.015mol/L) 6. Diphenylamine 7. Perchloric acid 8.acetaldehyde 9. ice acetic acidexperimental steps )The preparation method is: take the mass concentration of sodium citrate 0.1g/ml solution (anticoagulant) 100ml, placed in 500ml berrott. Inject the chicken blood (about 180ml) from slaughtering live chickens into the beo bowl and stir with a glass stick to mix the blood well with the sodium citrate solution to avoid clotting. The blood is then poured into the centrifugal tube and centrifuged by 2min at 1000 rpm, at which point the blood cells settle at the bottom of the centrifuge tube. In the experiment, by removing the clarification fluid from the upper part of the centrifuge tube by using a straw, you can obtain chicken blood cell fluid (if there is no centrifuge, the blood in the beech can be placed in the refrigerator, rest for a day, so that the blood cells precipitate themselves).
1.to extract the nuclear material of chicken blood cellsthe prepared chicken blood cell fluid 5 ml to 10 ml, into 50 ml berries. Add 20 ml of distilled water to the beech and stir 5min thoroughly with a glass stick to speed up the rupture of the blood cells. Then, use a funnel with gauze to filter the blood cell

to 500 ml of beaker, take its filter.

2 .DNAin the nuclei of dissolved cells adds 40 ml of sodium chloride to the filter with a solution of 2mol/L and shakes the beech to mix it evenly, when the DNA carrier solution is dissolved.

3 .to extract the DNA containing the viscosealong the inner wall of the beech slowly add distilled water, while using a glass stick to gently stir, when the beech appears in the silk, pay attention to observe what color the silk. Continue to add distilled water, the solution will appear more and more viscous. Stop adding distilled water when the viscous material no longer increases (at this point the concentration of sodium chloride in the solution is equivalent to 0.14mol/L).
4 .to filter the viscous materialcontaining DNAwith a funnel with multiple layers of gauze, the solution in step 3 is filtered into a 500 ml beaker, and the DNA-containing viscose is left on the gauze.
5 . of DNA and then dissolved 1 50 ml beoth, the amount of substance injected into the bea cup sodium chloride concentration of 2mol/L solution 20 ml. Clamp the viscous material on the gauze into the solution of sodium chloride with a blunt tweezer and stir constantly with a glass rod to dissolve the viscous material as much as possible in the solution.

6 . 1 100ml beaker is taken from a sodium chloride solution containing DNA is filtered, and the solution in step 5 is filtered with a funnel with two layers of gauze. The filter is taken and the DNA is dissolved in the filter.

7 . Extracts DNA containing less impurities in the above filtered solution, adds 50 ml of the cooled solution with a volume fraction of 95% alcohol (using cooled alcohol, which is better for the coagulation of DNA), and stirs with a glass rod, which contains less impurities. Roll up the silk with a glass rod and use filter paper to absorb the moisture from the top. The main component of this silk is DNA. Pay attention to what color the silk is.

8 . Dna identification take two 20 ml test tubes, each added sodium chloride in a solution concentration of 0.015mol/L 5 ml, the silk into one of the test tubes, stirred with a glass rod, so that the silk dissolved. Then, add 4 ml of diphenyl reagents to each of the two test tubes. After mixing evenly, place the test tube in boiling water
heat
5min, after the test tube cools down, observe and compare the changes in the color of the solution in the two test tubes. Fill in the results of the observations in the Lab Report Book.




the change in the color of the solution



8 in the two test tubes in step 8? The conclusions will be filled out in the Experimental Report Book.

2. Why remove the fluid from the blood when extracting DNA from chicken blood?

3. Distilled water is required for both step 1 and step 3, does the two additions work the same way? Why?




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