D:science/genetics/buildingdnalab 2/2002
Name ______________________ Discovering DNA Structure
Section _____________________
D = deoxyribo
N = nucleic
A = acid
DNA contains the information for carrying out the activities of the cell. How this information is coded or passed
from cell to cell was at one time unknown. To break the code, today you will do a paper lab to determine the
structure of DNA and show how the genetic code is carried. Each member of your group has a molecule called
a NUCLEOTIDE. DNA is made up of repeating units of nucleotides.
Color the nucleotides using the following key:
Deoxyribose = red Phosphate = blue
A (Adenine) = green C (Cytosine) = yellow
G (Guanine) = purple T (Thymine) = orange
1. Look at your nucleotide and the nucleotides of the other members of your group. What are the THREE
common parts of a nucleotide?
2. What is the ONE part of a nucleotide that differs among the four DIFFERENT nucleotides in your group?
3. List the four different kinds of nitrogen bases.
Manipulate the nucleotide pieces until you find the best fit. Join the nucleotide molecules in your group together
like a puzzle. Use tape to connect and reinforce the molecules. You now have a molecule of DNA.
4. In the space below, explain WHERE the nucleotide molecules connect to each other.
5. A real DNA molecule consists of THOUSANDS of these pairs of nucleotides. What is the pairing
arrangement of nitrogen bases?
_________ pairs with ________and _________ pairs with __________
6. Are there always going to be an EQUAL number of adenine and thymine nucleotides in a molecule? Why?
7. Are there always going to be an EQUAL number of guanine and cytosine molecules in a molecule of DNA?
Why?
8. Scientists abbreviate the nitrogen bases by using the first letter of each base. So,
A always binds to ____
G always binds to ____
