Name:__________________________ Period: 1 2 3 4 5 6 7 Date:____________________
Strawberry DNA
Extraction Lab
Background Information:
DNA (deoxyribonucleic acid) is the blueprint for every cell. As a blueprint, DNA tells each and
every cell what its function and structure needs to be. The DNA found in strawberry cells can be
extracted using common, everyday materials. We will use an extraction buffer containing salt, to
break up protein chains that bind around the nucleic acids, and dish soap to dissolve the lipid
(fat) part of the strawberry cell wall and cell membrane. This extraction buffer will help provide
us access to the DNA inside the cells.
Lab Materials:
 Heavy Duty Ziploc Bag (Freezer or Storage Bag)
 1 Strawberry
 10 mL DNA extraction buffer (soapy, salty water)
(900mL water, 50mL dishwashing detergent, 2
teaspoons of salt)
 Coffee Filter or Cheesecloth
 Funnel
 50 mL Test Tube
 Glass Rod, Inoculating Loop, or Popsicle Stick
 20 mL Ethanol (needs to be cold)
Lab Procedure:
1. Place one strawberry in a Ziploc bag.
2. Smash/grind up the strawberry using your fist and fingers for 2 minutes. Be careful not to
break the bag.
3. Add the provided 10mL of extraction buffer (salt and soap solution) to the bag.
4. Kneed/mush the strawberry in the bag again for 1 minute.
5. Assemble your filtration apparatus as shown in the picture to the upper right.
6. Pour the strawberry slurry into the filtration apparatus and let it drip directly into your test
tube. The filtration process may take some time so be patient and make sure that your mixture is
completely filtered before you move on.
7. Slowly pour 20mL of cold ethanol into the test tube. Take one minute and observe what is
happening inside of the test tube.
8. Carefully dip the inoculating loop or glass rod into the tube where the strawberry extract and
ethanol layers come into contact with each other. Observe what happens.
Lab Questions:
1. What does one single strand of DNA look like? Draw and describe this shape below.
2. At the conclusion of this lab when you had combined many strands of DNA together what
did they look like? Draw and describe the way it looked below.
3. Before any cell in our bodies undergoes mitosis it copies its DNA. Why is it important that
each cell has an individual copy of DNA?
4. What is the relationship between genes, chromosomes, and DNA? How are they organized
inside of a cell?
5. DNA codes for ___________ which are the building materials for cells, tissues, organs, and
organ systems within our bodies.
6. It is important that you understand the steps in the extraction procedure and why each step
was necessary. Each step in the procedure aided in isolating DNA from other cellular materials.
Match the procedure with its function:
Procedure
A. Filter strawberry slurry through cheesecloth
B. Mush strawberry with salty/soapy solution
C. Initial smashing and grinding of strawberry
D. Addition of ethanol to filtered extract
Function
______ To precipitate DNA from solution
______ Separate components of the cell
______ Break open the cells
______ Break up proteins and dissolve cell
membranes
7. Each strawberry cell has 8 chromosomes. How many chromosomes does each of your cells
have?
8. For the final question for this lab list any and all information you have learned about DNA
this year. Please write at least 4-5 sentences summarizing what you have learned. You can
definitely use some of the information in the questions above if needed.