Making a Candy Model of DNA
You and 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 phosphate group and a nitrogen base.
You and your partner will be graded on how well you follow directions and the quality of your model.
DNA Model
Materials
DNA Part
Caramel
deoxyribose sugar (S)
Twizzlers
phosphate group (P)
Toothpicks
Strong bonds between
phosphates and ribose
sugars.
adenine (A)
thymine (T
cytosine (C)
guanine (G))
Toothpicks
hydrogen bonds
Information
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.
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 molecule on one strand
and then pairs up with the complementary base
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.
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!
Be sure that working surfaces and
hands have been cleaned before
starting this activity, if you intend to
consume your models after finishing.
Information!
Cut Twizzler into small equal size
pieces
They will be your Phosphates that will
bond 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 any
sequence of three (3) base
pairs.
Connect two different colored
candies that 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 QuestionsThe 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.