We have been studying Biology this year, and our first nine weeks have focused on biochemistry which is really hard! In order to get both of us through it, we did as many hands-on activities as we could, trying to make some abstract concepts more concrete. Here is a sampling of what we've been learning and doing.
After learning that all matter, including life, is made up of the elements found on the periodic table, and that the compounds and reactions of those elements are what make life possible (creating energy, water, carbohydrates, fats and oils also known as lipids), we were ready to jump into the notion of proteins and DNA.
First, we made a large paper chain because proteins are long chains of molecules called amino acids. Each paper loop represents an amino acid, and the chain represents the primary structure of the protein. The sequence of the amino acids is called the polypeptide chain and is represented by the different colors of paper used. We coiled our polypeptide chain on the floor to represent the spiral helix that is also known as the secondary structure of the protein.
We learned that while the proteins are the building blocks of cells, blueprints and managers are needed to instruct the cell. This is the job of nucleic acids. Nucleic acids contain the genetic code of a cell. There are two kinds of nucleic acids. RNA and DNA. We learned about both, but made a model of DNA using candy.
In DNA the "backbone," which is represented by the rope candy, is made up of alternating sugar and phosphate. The third part is the base. The bases face each other and pair up in specific ways: G (guanine) with C (cytosine), and A (adenine) with T (thymine).
By seeing one side of a DNA helix, you can predict the components of the other side based on these pairing rules.
We also did an experiment where we extracted the DNA from a piece of potato. First we blended the potato with distilled water, added a few drops of laundry detergent to remove the lipids and proteins from the cell membranes, and filtered it into a beaker.
Then we cooled the substance in an ice bath and added meat tenderizer to remove proteins attached to the DNA. Then we added ice cold ethanol creating a separate layer on top of the water and let it stand for 3 minutes. We gently stirred a glass rod in the test tube and began to see a white layer of DNA form between the two layers.
Being able to see the DNA was really cool, and Luna is excited to be able to look at cells and other life material as we move forward in our study. Biology has been hard so far, but we think we're heading to the exciting part!