Biology - HOT Science Lab

Teacher
DNA Extraction Lab
NGSSS:
SC.912.L.16.3 Describe the basic process of DNA replication and how it relates to the
transmission and conservation of the genetic information. (AA)
Purpose of Lab/Activity:
To observe DNA in an organism.
To compare and contrast the amount of DNA found in different individuals of a species.
Prerequisites:
Students should have already been introduced to the structure of DNA including the
phosphate backbone, deoxyribose sugar location, and the nucleotides found within it
such as Adenine (A), Cytosine (C), Guanine (G) and Thymine (T).
Students should know that all living organism contain DNA and DNA is contained within
the nucleus of the living organism.
Students should have been introduced to chromosome number of different organism i.e.
haploid, diploid, and etc.
Materials (per group):
Ziploc baggies
Small (10 mL) graduated cylinders
Beakers or cups for straining
Cheesecloth
Test tubes and containers or racks to
hold them
Wood splints or disposable
inoculation loops
Strawberries
Extraction solution (10% shampoo
and a dash of salt)
Ice cold ethanol (70% pharmacy
ethanol will work)
Procedures: Day of Activity:
Before
activity:
During
activity:
What the teacher will do:
a. Prepare the DNA extraction buffer. In a container add 900mL water, then
50mL dishwashing detergent (or 100mL shampoo), and finally 2 teaspoons
salt. Slowly invert the bottle to mix the extraction buffer.
b. Be sure to provide different size strawberries and to have enough
strawberries.
c. Keep ethanol in refrigerator or ice bath the night before experiment.
d. Discuss where in the cell the DNA is contained.
e. Pre-Lab questions:
1. What do you think the DNA will look like Answers may vary.
2. Where is DNA found DNA is found in the nucleus of a cell of an
organism.
What the teacher will do:
a. Ask students why an extraction buffer is needed. 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 nuclear membrane. This extraction buffer will help provide us
access to the DNA inside the cells.
Biology HSL Page 199
Curriculum and Instruction