In our lesson we were tasked with creating the double helix DNA with marshmallows, cocktail sticks, thread and jelly tots. From the picture below you can see we used our thread to string together the marshmallows which were the sugar phosphate backbone. The jelly tots were our nitrogenous bases. Green was adenine, red was thymine, purple was cytosine and yellow was guanine. Our cocktail sticks were the hydrogen bonds between the nitrogenous bases.
Below is a slideshow of some of the pictures I took while doing the modelling. The first is of all of our equipment we used sorted into the colours ready to create our DNA. The second is of us threading the sugar phosphate backbone. This was shown by pink and white marshmallows on pink string threaded with a needle. The third picture is of our nitrogenous bases which were attached at the to pink marshmallows. The cocktail stick indicated the hydrogen bond between the base pairings. The final picture is the end result of our modelling the DNA.
- Nucleotides
- Provide the energy currency of cells in the form of adenosine triphosphate (ATP). Also provides the building blocks for inheritance in the form of DNA / RNA. A nucleotide is the sugar phosphate backbone and an organic nitrogenous base
- Nitrogenous Bases
- They are the purine pairs, most commonly found as adenine and guanine / cytosine and thymine.
- Purine
- It is two rings which contain nitrogen. Purine is a general term for some nitrogenous bases. Examples include adenine and guanine
- Pyrimidine
- It is one ring which contains nitrogen. Pyrimidine is a general term for some nitrogenous bases. Examples include cytosine, thymine and uracil
- Phosphate
- PO43- is part of the nucleotide. It is present in the cytoplasm of every cell. Nucleotides are acidic and carry a negative charge due to the phosphate group
- Pentose Sugar
- The sugar and phosphate are part of the nucleotide. They are joined by a condensation reaction.
- Double helix
- The iconic structure from which the sugar phosphate backbone has purine / pyrimidine base pointing inwards which causes the spiral pattern
- Anti-parallel
- The sugar phosphate backbones run against one another (one runs upwards the other downwards)
- Hydrogen bond
- The strands of DNA are held together between the complementary base pairs