STRAWBERRY DNA EXTRACTION FRUIT LOOPS STRAWBERRY DNA EXTRACTION

Did You Know… There are about 2 meters of DNA in each of your cells. If all the DNA in your body was put end to end, it would reach to the sun and back over 600 times (0.983 289 8912 AU - 1.016 710 3335 AU=> avg: 150M km / 93M miles x 600 = 90B km / 720M miles => 45 trillion cells – this is disputed, but definitely in the 10’s of trillions [10^13]. Human DNA is 98% identical to chimpanzee DNA My DNA is 99% identical to your DNA Institute for Stem Cell Research

Why Use A Strawberry??? Each strawberry cell has a lot of DNA! Domestic (store-bought) strawberry cells are octoploids (8 copies of each chromosome) 7 chromosomes per gamete => 56 chromosomes More or Less variability than diploid? Our cells only have 2 copies of each chromosome.

Lab materials…. Freezer bags 1 strawberry DNA extraction buffer Filter paper Funnel Ice cold 99% isopropyl alcohol Test tube Paper clip (or a similar object)

Why do we crush the strawberries? To break cell walls.

How do we make extraction buffer? - Combine 100 mL shampoo (w/o conditioner) 15 g non-iodized kitchen salt Fill with water to 1 Liter THIS WILL MAKE 1 LITER OF EXTRACTION BUFFER

Et voila, c’est ca: Un buffer

Why do we add soap to the extraction buffer? To break down/emulsify the lipids that make up the cell membrane and nuclear membrane. Once we break down the nuclear membrane, we have access to the DNA.

What is the purpose of adding salt to our extraction buffer? Salt will disassociate into + and – ions. This will uncoil the negatively charged DNA molecule.

Why do we use alcohol during the final steps of the lab? Alcohol is a polar substance. DNA is nonpolar, therefore, it is insoluable in alcohol. As a result, the DNA will precipitate (separate) forming long rope-like DNA molecules in the alcohol.

PROCEDURE Smash fruit in freezer bag. Add 10 mL of extraction buffer. Continue mashing. Filter (with filter paper) smashed fruit into a test tube. Add 10 mL of alcohol to test tube. DNA will precipitate. Use paper clip to “grab” DNA!!!