Making a Candy Model of DNA

Youand your partner will show how the basic structure and double helix shape of deoxyribonucleic acid is important in the process of replication. To learn how the nucleotides are formed, and how it all fits together.

Nearly every cell in our body contains DNA, and it is a very important molecule as it contains important information (genetic information) to tell the cells in our body what to do.

DNA is a polymer – that means it is made from lots of small, almost identical, units joined together to make a big molecule. Each unit of DNA, called a nucleotide, contains a sugar molecule (deoxyribose), a phosphategroup and a nitrogenbase.

You and your partner will be graded on how well you follow directions and the quality of your model.

DNA Model
Materials / DNA Part / Information
Caramel / deoxyribose sugar (S) / Sides of DNA: The sugar bonds with the phosphate, then the sugar from this unit links with another phosphate and so on until you get a long chain called the sugar-phosphate backbone.
Twizzlers / phosphate group (P)
Toothpicks / Strong bonds between phosphates and ribose
sugars.
adenine (A) / The nitrogen bases are adenosine, cytosine, guanine and thymine. These are usually symbolized to A, C, G and T. Each base is attached to its own sugar moleculeon one strand and then pairs up with the complementarybase on the other strand – turning the two strands into a kind of twisted ladder. The rules for base pairing are very strict. A always pairs with T; and G always pairs with C.
thymine (T
cytosine (C)
guanine (G))
Toothpicks / hydrogen bonds / Connect the nitrogen bases. The slightly positively charged hydrogen atoms of the bases are attracted to the lightly negatively charged atoms of nitrogen or oxygen on the complementary base.
Steps / Directions! / Information!
/ Be sure that working surfaces and hands have been cleaned before starting this activity, if you intend to consume your models after finishing. /
/ Cut Twizzler into small equal size pieces / They will be your Phosphates thatwillbond with sugar..
/ Use all the material to create your sides first.Color code your Bases. / DNA molecules are actually formed by building blocks of nucleotides!
Nucleotide is made up of one nitrogen base attached to one ribose sugar molecule which is bonded to one phosphate molecule.
/ Build the DNA model into anysequence ofthree (3) base pairs.
Connect two different colored candiesthat represent the bases together using the toothpicks.
When connecting the base pairs be sure to connect the ones that pair naturally in DNA. For example, adenine pairs with thymine and cytosine pairs with guanine. /
/ Connect the “rungs”
/ Grasp the completed molecule by the base pair at each end of the strand twist the structure slightly and you have a DNA model! Be careful it may not twist easily. Wood does not bend. /
/ After you demonstrate this to your teacher, you may dispose of or eat your models. This is one case where you may eat your science project, if you have kept everything clean and your teacher gives permission. Be sure to remove toothpicks before you eat!!! Clean up, being sure that no toothpicks or sticky residue is left behind. Wash your hands!Answer the Analysis Question in your composition book.

Analysis Questions

The whole model represents ______

The Sugar is called ______

What makes up a single Nucleotide?

What are the base pairing rules for DNA______

Write down the sequence of both of your strands.

Transcribe one of your strands to represent M RNA.