DNA Extraction
Banana, Strawberry, Corn, Pea
Why DNA Isolation?
• The extraction of DNA from cells & its purification are of primary
importance to the field of biotechnology & forensics.
• Extraction & purification of DNA are the first steps in the analysis and
manipulation of DNA that allow scientists to detect genetic disorders,
produce DNA fingerprints of individuals, and even create genetically
engineered organisms that can produce beneficial products such as insulin,
antibiotics, and hormones!
Process & Procedures
• You will be extracting DNA from at least 3 out
of the 4 fruits & vegetables. Your choices
include:
– Strawberries
– Peas
– Corn
– Bananas
Question & Hypothesis
Question: Which fruit/vegetable will produce
the most DNA?
Hypothesis: You will not be able to add a
“because” to your hypothesis, as we have not
completed background research. Just state
which fruit/vegetable you think will produce
the most DNA.
Procedures
1. Construct a data table. Determine how you will collect
quantitative data (for a graph in your lab report).
2. Working in pairs, use a weigh boat to measure 4g of food.
3. Mash the food using the mortar and pestle (2 min).
4. Add 12 mL of extraction buffer & continue mashing for an
additional minute.
5. Allow mixture to sit for 5 minutes.
6. Pour mixture into a funnel lined with filter paper and
allow the liquid and solids to separate.
7. Pour liquid into a test tube. Add 7 mL of 90% ethyl alcohol
and observe the DNA precipitate out of the solution.
8. Use a stirring rod to gather DNA.
Information to include in your lab (part
of Background Information)
• Research the answers to the following
questions:
– What was the purpose of mashing the food with a
mortar and pestle?
– The extraction buffer is composed of soap/water,
meat tenderizer, and salt. What is the reason for
using each ingredient?
– At the end we added ethyl alcohol to the test
tube. Why?