StrippinG BananaS DNA
After this post you will be able to see the chromosomes of a banana.
But what are chromosomes? Keep reading and let`s have fun stripping the DNA of bananas.
Since Christmas is coming we wanted to make a last fun contribution to our BananitaBlog. A curious activity we can share with the family, which will delight young and old.
Nevertheless, to start with the banana experiment we previously need to answer a few questions:
What do we have in common with bananas?
Do you know what exactly is DNA?
Can you define what a cell is?
How is DNA stored in cells?
Can we see the DNA of a banana without a microscope?
Believe it or not, we share about 50 percent of our genes with them. And why is this not surprising? In fact, all genes are made of deoxyribonucleic acid, better known for its abbreviation DNA.
But do not panic! This does not mean that we all are bananas.
As easily explained in the article from New Scientist,:
“The 50 per cent figure for people and bananas roughly means that half of our genes have counterparts in bananas. For example, both have some kind of gene that codes for cell growth, though these aren’t necessarily made up of the same DNA sequences” (From Mark Peplow, Science Media Centre, The Royal Institution)
DNA is an organic chemical of complex molecular structure found in all cells (and in many viruses, as we already know thanks to COVID-19).
Its structure is a double-helix, a spiral consisting of two DNA chains wound around each other. This helix contains the instructions responsible for the development of an organism. In other words, DNA is the language of life. That’s why we also call it the genetic code.
To better understand how can we visualize DNA from bananas, we may need to acknowledge how it is stored. It is hence necessary to answer the following: what is a cell?.
A cell is the smallest living thing in all organisms.
Cells from humans and bananas are type eukaryotes. These cells consist mainly of five parts:
1 – Cell wall
2 – Cell membrane
3 – Cytoplasm
4 – Nucleus
5 – Cell organelles
”Within a cell, DNA is organized into dense protein-DNA complexes called chromosomes. In eukaryotes, the chromosomes are located in the nucleus, although DNA also is found ln mitochondria and chloroplasts. In prokaryotes, which do not have a membrane-bound nucleus, the DNA is found as a single circular chromosome in the cytoplasm”. (Source: Britannica Science).
Yes, we can!. We can see the chromosomes that carry this genetic information in the form of genes. And, most amazing, you can do it with stuff we all have at home.
To do this, how will we extract the DNA from the banana cells? Let´s find out the stripping of bananas DNA.
Even though it may sound complex, it is very easy to do. As already mentioned, the DNA helix can be taken out of the cell’s nucleus, using very ordinary things that will allow us to break the cell wall and leave the nucleus free. So, let’s knock down the cells walls to visualize banana DNA!
This is an experiment introduced by a popular scientific disseminator from Spain, Déborah García Bello (@deborahciencia). She showed on TV the different steps we must follow to see banana DNA at home.
What do we need?
1 – A plastic bag
2 – 100 ml water
3 – 10 ml dishwater detergent
4 – A strainer
5 – A syringe
6 – 10 ml pineapple juice
7 – 10 ml alcohol
1 – Put the banana in a plastic bag and smash it. By smashing it we increase the reaction surface.
2 – Pour around 100 ml of water in the bag.
3 – Pour around 10 ml of dishwater detergent. The latter will remove the layer surrounding the outside of the cell known as the phospholipid. In other words, the detergent breaks down the wall of the cells releasing their nucleus.
4 – We strain the mixture to separate the DNA from other parts of the cell such as organelles, cell walls, …
5 – With a syringe we take 10 ml of the liquid and pour it into a test tube or something similar
6 – Add 10 ml of pineapple juice . Why? Because the DNA is wrapped in proteins called histones and the pineapple juice has an enzyme called bromelain able to unravel it.
7 – The last step is to add alcohol (10 ml). This will allow us to see the DNA strands because DNA solubility in alcohol is very low.
Below the result you will see:
Source: TVG (Televisión de Galicia)
We hope you enjoy the experiment and can get all the info from bananas!
And, even though we’re taking a break, don’t get completely disconnected from BananitaBlog 🍌⌨️😊.