DNA Extraction Principles

How do you get DNA out of a whole organism?

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

What does the detergent and NaCl do to the cell parts?

Mashing the berry disrupts the cells and membranes

What is in the bag?1. Clumps of whole cells and nuclei 2. Cell Membranes: lipids and protein 3. Organelles made of protein4. Plant Cell Wall: cellulose and protein5. DNA bound to protein

What does detergent and NaCl do?

1. 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?

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?

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

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 filter5. DNA precipitates in cold alcohol and is

spooled out.

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 individualstrands of DNA?