Download DNA Model Activity

Name: _____________________________
DNA Model Activity
What is the structure of DNA?
Background Information
DNA (deoxyribonucleic acid) is found in the chromosomes of all living things. It is the chemical
of which genes are composed. With an understanding of this all-important molecule, scientists
know how chromosomes can duplicate during cell division and transfer genetic information to
new cells. They also understand the functioning of DNA instructions sent out to direct the
activity of protein formation within the cell.
The DNA molecule is in the shape of a DOUBLE HELIX (spiral). The molecules making up the
DNA molecule are DEOXYRIBOSE SUGAR, PHOSPHATE GROUP, and NITROGEN
BASES. A molecule of deoxyribose sugar bonds with a phosphate group with a strong
PHOSPHODIESTER BOND. The deoxyribose, phosphate and a nitrogen base together form the
structural unit of DNA called a NUCLEOTIDE. There are four different nitrogen bases available
to form nucleotides. The nitrogen bases are ADENINE, GUANING, THYMINE, and
CYTOSINE. Adenine and guanine are larger molecules and are called purines. Thymine and
cytosine are smaller molecules and are called pyrimidines.
In this activity, you will work with hour lab partner to construct a model of DNA using paper
cutouts, colored pencils, and tape.
Procedure
1. Fill in the following key with the colors you will use in your DNA model. Be sure to
choose a different color for each component of the DNA molecule.
Structural component of DNA
Phosphate
Deoxyribose Sugar
Adenine
Guanine
Thymine
Cytosine
Color
2. Color the pieces on the DNA structure sheets according to the table you filled out above.
You will need to color:
6 Adenine
6 Cytosine
6 Guanine
6 Thymine
24 Deoxyribose
24 Phosphates
3. Once you have finished coloring all of the pieces, cut them out so you will be able to
assemble the nucleotides that will build your DNA molecule.
4. Create one of each of the different nucleotides that will build your DNA molecule. Show
these nucleotides to your teacher for approval BEFORE you assemble your DNA
molecule.
Teacher: ________
5. Use the following sequence of nitrogen bases when assembling your molecule of DNA.
T A C G T A C A T G C G (right strand)
What will the
complementary
strand look like ?
__________________________________ (left strand)
6. Create the strands of DNA by taping the nucleotides in the appropriate order. It is helpful
if one partner is responsible for creating the right strand of the DNA molecule and the
other partner creates the left strand.
7. Once both partners have each side of the DNA correctly assembled, connect the two
strands together. REMEMBER:
Adenine ALWAYS joins with _________________
Guanine ALWAYS joins with _________________
Analysis Questions:
1. What two chemicals make up the sides of the DNA molecule?
2. What chemicals make up the “rungs” (steps) of the DNA ladder?
3. What makes Adenine and Guanine similar?
4. What makes Cytosine and Thymine similar?
5. What type of bond holds the nitrogen bases together?
6. What are the parts of a nucleotide?
7. How many different nucleotides are possible in any DNA molecule?
8. How does the location of DNA differ between prokaryotes and eukaryotes?
9. How does the structure of DNA differ between prokaryotes and eukaryotes?
10. What is the name that is used to describe the three dimensional shape of DNA?
11. If four GUANINE nucleotides are found in a DNA segment, how many CYTOSINE
will be found in the same DNA segment? Explain your answer!
12. The following represents the nitrogen bases found on a DNA molecule. In the spaces
provided, name the complementary nitrogen bases that would pair with the bases
provided.
THYMINE
________________
ADENINE
________________
GUANINE
________________
______________
CYTOSINE
______________
THYMINE
CYTOSINE
_________________
_______________
THYMINE
ADENINE
_________________
CYTOSINE
_________________
_______________
ADENINE
_______________
GUANINE