DNA Extraction

http://gslc.genetics.utah.edu/units/activities/extraction/

MATERIALS

• Dried split peas

• Dishwashing detergent

• Isopropyl alcohol

• Meat tenderizer

• Small cup or beaker

• Spoon

Start with the peas

Blend the peas with water and a little salt until you have “pea soup”

Why do we blend the peas?

• The blender separates the pea CELLS from each other

Put the strained pea soup in a cup

Add a squirt of dishwashing detergent

Let the mixture sit for 5 minutes

What does the detergent do?

• Each pea cell is surrounded by a cell membrane

• DNA is in the nucleus of a cell, which is also surrounded by a membrane

The membranes must be broken open in order to get the

DNA out of the cell

Detergent:

• Breaks apart membranes by attaching to the lipids (fats) & proteins in the membranes

The cell and nuclear membranes have been broken apart,

as well as all of the organelle membranes,such as those around the mitochondria and

chloroplasts.So what is left?

• Proteins • Carbohydrates (sugars) • DNA

Add a pinch of meat tenderizer to the mixture

Why?

• Meat tenderizer is an ENZYME– A protein that helps chemical reactions

happen more quickly

• The enzymes in meat tenderizer break apart proteins

The DNA in the nucleus is surrounded by proteins

The meat tenderizer cuts away the proteins from the DNA

Stir very, very GENTLY!

Tilt your cup & slowly pour a layer of alcohol on top of the pea soup

mixture

• DNA will float up into the alcohol from the pea soup