Strawberry DNA extraction questions – Please write the question and answer
using complete sentences on a separate piece of paper, typed (30 pts.)
1. What kind of cells are strawberries made of? What is the main source of
sugar found in plants? Where is DNA found in these cells? (2 pts.)
2. What structure surrounds the cells of strawberries? Describe it. What do
you think strawberries naturally contain that make them a good choice if we
want to break down this structure? (Hint: think back to the potato enzyme
lab and why potatoes change color)(4 pts.)
3. What kind of molecules make-up the membranes of cells? How are these
molecules similar to triglycerides like vegetable oil? What happens when
these molecules are exposed to soap? (5 pts.)
4. Explain how the extraction buffer prepares DNA to be extracted? In addition
to the soap, what was the purpose of salt in the buffer (Hint: What else is
found in the membrane)(4 pts.)
5. DNA is polar and less dense than water. Where would DNA molecules be
found if placed in water? (2 pts.)
6. When alcohol was slowly added to the solution, did it form the top layer or
the bottom layer in the graduated cylinder. Why? Why do you only see DNA
after you put in alcohol (4 pts.)
7. What was the purpose of using cold alcohol? (3pts.)
8. A single molecule of DNA is invisible to the unaided eye. However, you were
able to clearly see the DNA in today’s lab. Explain. (3 pts.)
9. Many times, this lab is done using human cheek cells. Why would eating
cornflakes or a bagel for breakfast or eating chips at lunch be a bad idea
before doing this lab? (3 pts.)