DNA Extraction from Wheat

Materials:

• 200 ml beaker 100 ml tap water
• 1.5 g RAW wheat germ
• thermometer balance
• water bath at 50-60 degrees Celsius
• plastic spoon
• glass rod-bent or inoculating loop
• 10ml graduated cylinder ice bucket and ice
• 3g Adolph's 100% Natural Tenderizer (unseasoned) - the tenderizer has to contain papain.
• filter paper
• solutions: Sodium Bicarbonate - ph 8.0: 8.4g baking soda to 100ml tap water 5ml full strength Palmolive liquid 95% ethanol

Procedure:
1. Prepare water bath at 55 degrees Celsius
2. Fill 200ml beaker with 100ml water and place into water bath. Mix in 1.5g wheat germ with plastic spoon into beaker until dissolved as much as possible.
3. Add 5ml Palmolive. Maintain temperature at 55 degrees and stir occasionally. Caution: do not allow temperature to exceed 60 degrees because this may denature DNA.
4. Dissolve 3g meat tenderizer in the wheat germ solution and add 10ml baking soda solution. Maintain the temperature at 55 degrees for 10 minutes.
5. Place the solution on ice for 15 minutes.
6. Using the 10ml graduated cylinder, gently layer 10ml of 95% ethanol over the solution, forming a second layer.
7. Use the glass rod/inoculating loop to spool the DNA which precipitates at the interface. DO NOT did at the bottom or you will disturb the waste wheat germ.
8. Pull as much DNA out of the solution as possible and place on the filter paper to dry overnight.
9. Weigh the DNA you isolated.

Data/Observations:
Record your observations of DNA and grams of dry DNA = _________g

Analysis:
1. Draw a picture of a wheat germ cell and label the cell wall, cell membrane, nuclear membrane and DNA.

2. With regard to the structure of the cell membrane/nuclear membrane, what was the purpose of the Palmolive detergent?

3. With regard to the structure of the cell membrane/nuclear membrane, what was the purpose of the meat tenderizer?

4. What was the purpose of the baking soda? Would we have been able to extract the DNA from the wheat germ cells without the baking soda? Why or why not?

5. What would have happened if we mixed the 95% ethanol into the solution instead of gently layering it on top?

Questions? Comments??
Shannon Tice