I am using the following protocol to extract chromosomal DNA from bananas:
- Cut up one banana into small pieces, approximately (1 cm3)
- Add ½ a cup of warm salt water and the banana pieces into the blender and set to max for 5-10 seconds
- Poor into a beaker and add 1 teaspoon of detergent to the beaker
- Stir for 5 mins with a spoon to break down the plasma membrane
- Place the mixture into a centrifuge for 30 seconds
- Pour the mixture through a gauze with a beaker catching the liquid underneath
- Smoothly pour cold ethanol into the mixture at a 1:1 ratio so a clear layer of liquid will form on top of your mixture
Why is the centrifuge step (5) needed? Why would that increase the yield of DNA?