Purpose: DNA is present in all living organisms. The purpose of this lab is to extract DNA (get DNA) out of cells so that we can see it.
Materials: cups, spoon, knife, filter, kiwi, detergent, water, salt, pipette, test tube, ethanol, lab
Procedure: You must check off each step as you do it!
Questions: Do these while you mix up the kiwi solution (10 minutes).
1. What is DNA?
2. What four nucleotides make up DNA?
3. What are the three parts of a nucleotide?
4. How many chains of nucleotides make up a DNA model?
5. Read the paragraph below and then answer the questions related to it:
-Extract means to get something out of something else. Today we are extracting DNA, which means we are pulling DNA out of cells. To pull DNA out of cells, we must first separate the DNA from the rest of the cell. As you know, DNA is found in the nucleus. In order to break down the plasma membrane and open up the nucleus, we add detergent which breaks down the membranes by breaking apart the lipids that make up the membranes. We then add salt, which allows the DNA to separate from the rest of the cell.
A. What does extract mean?
B. What do we need to do to get DNA out of the cells?
C. Why do we add detergent and salt to the kiwi cells?
D. How does the detergent break down the plasma membrane?
Questions: Do these while you wait for the DNA to come out of the solution (3 minutes).
1. Read the paragraph below and answer the questions related to it:
The kiwi mixture was added to the cold alcohol to separate the DNA from the rest of the cell. When alcohol is added to the kiwi mixture, everything else is heavy and stays in the bottom of the mixture. The DNA is lighter, so it floats to the top of the alcohol mixture. You should see little pieces of white string which are the DNA.
A. Why do we add alcohol to the kiwi mixture?
B. Why does the DNA separate when added to the alcohol?
C. Why do you think you’re not supposed to shake the test tube while the DNA is separating?