DIY Biology experiment: Extracting DNA from a banana
DNA is a biological molecule that contains genetic information of a living thing or people. A genetic code found in DNA provides information about all the components required for the reproduction of life. The process of extracting DNA for experiments is an important part of biology. However, DNA extraction is tedious and beyond the levels of school goers. Nevertheless, this complex process can be turned into a fun, DIY experiment for high school students by using bananas.
What is DNA extraction?
DNA extraction is a technique to purify DNA by using physical or chemical methods from a sample separating DNA from cell membranes, proteins and other cellular components. This experiment is a great way to make teenagers fall in love with biology and can help them learn about concepts such as mashing, filtration, precipitation and extraction.
The Experiment
DNA extraction is mainly done to study the genetic causes of an ailment or for the purpose of developing drugs, vaccines and other diagnostics for the same. Youngsters who are interested in different fields of biology, such as microbiology, forensic science, botany and zoology, are often fascinated by this experiment. Read on to know how your school goer can carry it out at home.
What you’ll need
- Banana
- Salt
- Warm water
- Liquid soap
- Blender
- Toothpick
- Strainer
- Glass jar
- Rubbing alcohol
- Knife
Step-by-step guide
Here are the steps that your school goer needs to follow while carrying out this experiment. Help him follow these.
- Take a banana and cut it into tiny pieces using a knife to expose its cells.
- Now add the pieces into a blender, followed by a teaspoon of salt and pour half a cup of warm water into it. The salt will help the DNA remain together during the process of mashing.
- Now mix all the ingredients in the blender. The goal is to not make it unnecessarily runny.
- Next, pour the mixture into the glass jar set aside using the strainer. Fill up the jar till its half full.
- Add two teaspoons of liquid soap onto the mixture and stir gently. Make sure bubbles are not formed during this process. This is where the soap helps the cell membranes to break down and release the DNA.
- Now pour the cold rubbing alcohol down the side of the glass jar and stop once you reach the top. The goal is to make sure that two separate layers are formed, the bottom layer being the banana mixture and the top layer being the alcohol.
- Now, wait patiently for 5 minutes for the DNA to separate from the solution.
- Once the long and stringy DNA is extracted and floats near the surface, carefully use the toothpick to extract it. The goal is to twist the DNA gradually and try and remove it once it appears at the top layer.
How did this experiment make DNA extraction from banana possible?
There are primarily four steps of extracting DNA from a banana. First is mashing that helps in exposing a greater surface area to extract the DNA from. This also includes addition of the liquid soap to help break down the cell membranes to release the DNA. Second step was filtration or separation where the mixture is poured through the strainer that allows the DNA and other cellular substances to collect. Next comes the step called precipitation where the alcohol is poured that further allows the DNA to separate from the other cellular substances. Finally, the DNA is extracted from the solution using toothpicks.