Why is extracted dna white

This is strawberry DNA. The DNA will clump together and float to the top of the alcohol layer. Skip to menu Skip to content Skip to footer. Site search Search. Site search Search Menu. Strawberry DNA extraction activity. What you'll need to get started Strawberries Zip-closure sandwich bag DNA extracting solution mix about 1 tablespoon of dish detergent and 1 teaspoon of salt into 1 cup of water Plastic cup Gauze, cheesecloth or coffee filter Rubber band Test tube or smaller cup Dropper or spoon Denatured alcohol eg.

Conducting your experiment Place a strawberry in a zip-closure bag and remove most of the air before you seal the bag.

Add 2 tablespoons of the DNA extracting solution. Continue mixing and mashing the bag in your hand. Take a photo of your findings and share your scientific success with your friends and family! Emergency Phone: These kits help extract DNA from particular cell types or sample types. However, they can be expensive to use routinely, so many labs have their own methods for DNA extraction.

The cells in a sample are separated from each other, often by a physical means such as grinding or vortexing , and put into a solution containing salt. The positively charged sodium ions in the salt help protect the negatively charged phosphate groups that run along the backbone of the DNA. A detergent is then added. The detergent breaks down the lipids in the cell membrane and nuclei. DNA is released as these membranes are disrupted.

This can be done by a variety of methods. Often a protease protein enzyme is added to degrade DNA-associated proteins and other cellular proteins. Let the solution sit for two minutes without disturbing it. The DNA will appear as transparent, slimy, white mucus which can be spooled up with the wood applicator stick.

Why do we use shampoo? What does the salt do? Why do we need to cool the mixture? What does the cold ethanol do? Discussion Questions To extract DNA from cells, what must you isolate it from in the case of a plant such as strawberry? What steps did we use to extract the DNA? What is DNA used for when it is extracted? After the cell walls have been disrupted during mechanical mashing of the fruit, the detergent in the shampoo disrupts the cell and nuclear membranes of each cell to release the DNA.

It does this by dissolving lipids and proteins that hold the membranes together. It also causes proteins and carbohydrates to precipitate. They are there to protect the cell from invasion by viruses. Once the nuclear membrane is destroyed by the soap, the DNA is now susceptible to the DNases and will quickly be degraded.

However, these enzymes are temperature sensitive and cooling the solution slows down the process of degradation. Everything except the DNA will dissolve in ethanol. The ethanol pulls water from the DNA molecule so that it then collapses in on itself and precipitates.

The DNA will become visible as white mucous strands that can be spooled with the wooden applicator stick.