Group+7+SUM13

=Strawberry DNA Extraction Lesson=



Strawberry DNA Media Strawberry DNA Student Worksheet

==== **Background:** This lesson plan is for the extraction of DNA from strawberries. Strawberries are an exceptional fruit to use for this lesson because each individual student is able to complete the process by themselves and strawberries yield more DNA than any other fruit (i.e. banana, kiwi, etc.). Strawberries are octoploid, meaning that they have eight copies of each type of chromosome. ====

Students will observe first hand that DNA is in the food that they eat. Students will learn the simple method to extract DNA and why each step is necessary due to the complex organization of DNA in cells. Students will learn why it is important for scientist to extract DNA from organisms.
 * Learning Objective: **

For each student: -heavy duty ziploc bag (freezer or storage bag) -1 strawberry -DNA extraction buffer (900mL water, 50mL dishwashing detergent, 2 teaspoons salt) -small plastic cup to hold extraction buffer -cheesecloth to fit in small funnel (4” X 4” should be appropriate) -small funnel -50mL vial / test tube -glass rod -inoculating loop -or popsicle stick -cold ethanol -ice
 * Materials and Equipment: **


 * Process: **// Total Duration: //// 10 minutes teacher prep before class 40-60 minutes in class //

__ Step: 1 Duration: 10 minutes __ Teacher may choose prior to class to 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.

__ Step: 2 Duration: 40 minutes to 60 minutes depending on class cooperation __

Lab procedures should be conducted as stated in the DNA Strawberry Student Worksheet Extraction (document is linked above). Modifications can be made based on the needs of the students. Some classes may decide for each student to add individual components of the extraction buffer to the Ziploc bag (roughly 2 tsp water, 1 tsp soap, 1 pinch salt), while other classes may choose to use the teacher prepared extraction buffer (from Step 1). When the students add ethanol to their strawberry extract, they will see the fine white strands of DNA precipitate. The DNA will form cotton like fibers that will spool onto the stirring rod/inoculating loop/popsicle stick.

Lab report and/or discussion questions. Discuss questions as a class to assess the students understanding and ability to communicate scientific concepts. Discuss why each step was needed and how this relates to the organization of genetic material.
 * Assessment: **

Source: http://gemsclub.org/yahoo_site_admin/assets/docs/StrawberryDNAExtra.4395135.pdf