Name: ___________________Period: ____

DNA EXTRACTION

Now that you’ve learned a little about DNA, you’re probably curious as to what it actually looks like! For this lab you will be extracting DNA from dried split peas. Follow the directions carefully to get the best results.

Materials: ½ cup Peas (100 ml)

1/8 tsp salt (less than 1 ml)

1 cup cold water (200 ml)

2 Tbsp. liquid dish detergent (30ml)

Meat tenderizer

Isopropyl alcohol

Test Tube

Stir stick

Step 1 : Blend! (teacher)

Put in a blender

½ cup peas (100 ml)

1/8 tsp. table salt (less than 1 ml)

1 cup cold water (200 ml)

Blend on high for 15 seconds.

The blender separates the pea cells from each other and breaks down the cell wall, so you

now have a thin pea-cell soup.

Step 2: Soapy Peas (teacher)

Pour the pea soup through a strainer into another container.

Add 2 tablespoons liquid detergent (30 ml) and swirl to mix.

Let mixture sit for 5-10 min.

STUDENTS:

Pour the mixture into test tube until 1/3 full.

Detergent breaks apart lipid bi-layer of cell membrane and nuclear membrane.

Step 3: Enzyme Power (students)

Add a small pinch of tenderizer and stir gently.

Tenderizer acts as an enzyme to cut proteins out of DNA to help unravel it.

Step 4: Alcohol Separation

Tilt test tube and slowly pour in alcohol down the side. Pour until alcohol amount

is the same as the pea mixture.

Let this sit for about 2 minutes. DNA will rise into the alcohol layer from the pea

layer. You can use a wooden stick or hook to draw the DNA from the alcohol.

Alcohol is less dense than other materials, creating a separate layer in which to

draw up DNA.

Analysis Questions:

1. Why was it important to use detergent once the peas had been blended?

2. Why was meat tenderizer used in the lab?

3. Which was more dense, the alcohol or the DNA? How did you know?

4. What did the DNA look like once it separated out of the pea mixture?

5. What are the four base pairs that make up a strand of DNA?

6. In what organelle of the cell is DNA found?

7. In your opinion, why is it important for scientists to study DNA? How can these

studies affect your life?