This document summarizes the steps to extract DNA from a strawberry. First, the berry is mashed to disrupt the plant cells and membranes. Detergent and salt are then used to dissolve the membranes and separate the DNA from proteins. The cell debris is filtered out while the small DNA and protein molecules pass through. Finally, cold alcohol is added to precipitate the DNA out of solution due to its insolubility, leaving purified DNA spooled on the collection stick.

1. DNA Extraction Principles How do you get DNA out of a whole organism?

2. How do you get DNA out of a strawberry? Plant Cell Wall: cellulose and protein matrix Cell membrane: lipids and protein Plant Cell Cytoplasm: proteins etc Nucleus: DNA & protein

3. What does the detergent and NaCl do to the cell parts? Mashing the berry disrupts the cells and membranes What is in the bag? Clumps of whole cells and nuclei Cell Membranes: lipids and protein Organelles made of protein 4. Plant Cell Wall: cellulose and protein 5. DNA bound to protein

4. What does detergent and NaCl do? Detergent: dissolves the membranes and disrupts proteins. 2. Na+ ions break apart the protein that is stuck to the DNA. How do we separate the clumps of cells from the small molecules?

5. Filtering -Clumps of cellular debris get stuck in the filter. -Small molecules flow thru. How do we get the DNA to separate from the pink liquid?

6. Precipitate the DNA with cold alcohol DNA is not soluble in cold alcohol All small molecules stay in solution except DNA Long strands of DNA spool onto the stick

7. Summary 1. Break open cells by mashing the fruit. 2. Dissolve organelles and cell membranes with detergent. 3. Separate DNA from proteins with salt: Na(+) is attracted to (–)DNA so it bumps off the protein. 4. Filter out the clumps with a coffee filter 5. DNA precipitates in cold alcohol and is spooled out.

8. DNA Properties a. Texture – strands of cellular DNA are very long (thus we can spool it) b. Solubility – DNA is soluble in water, insoluble in alcohol c. pH – ? d. Can you see individual strands of DNA?