Biology Student
EQ: If there are only four nucleotide types in DNA, why are all living things so different? / Enduring Understanding
Nucleic acids transfer genetic information from generation to generation.
/ DNA Model Lab / Broad Brush Knowledge
nucleic acid structure and function
Concepts Important to Know and
Understand
DNA Processes
/ Target
3) Construct a model of a DNA molecule and analyze its structure in terms of its function including: what makes up a nucleotide, nitrogen base and complementary base pairing rule, and double helix shape / Core Objectives
5. Identify the structure & function of
nucleic acids including their role in
biodiversity.

PURPOSE

To analyze the DNA molecule

Background Information
The control body of the cell is the nucleus. Rod-shaped structures in the nucleus called chromosomes contain the genetic material of the cell. This genetic material is made of DNA (deoxyribonucleic acid). DNA is found only in the nucleus of the cell.
The base building unit (monomer) of DNA is the nucleotide. A DNA nucleotide consists of three parts: a sugar (deoxyribose), a phosphate and a nitrogen base.
The DNA molecule is in the shape of a double helix, like a twisted ladder. The "rungs" on the ladder are the nitrogen bases and the sides are the sugar and phosphate. The four different DNA nucleotides are made from the four different nitrogen bases. cytosine (C), guanine (G), adenine (A) and thymine (T). According to the base pairing rule, cytosine always pairs with guanine and thymine with adenine.

Questions

1. What is DNA and describe it’s function?
2. What is the monomer (subunit) in DNA?
3. What are the three parts of the DNA monomer?
4. What is the name of the sugar in DNA?
5. What molecule(s) make up the sides (backbone) of the DNA “ladder”?
6. What molecule(s) make up the steps (rungs) of the DNA “ladder”?
7. What does adenine always bond with?
8. What does guanine always bond with?
9. What does cytosine always bond with?
10. What does thymine always bond with?
11. In the DNA picture to the right, label all the sugars with the letter S, all the phosphate groups with the letter P, and write the first letter of each nitrogen base.
12. How many nucleotides does this picture show?

DNA Model Lab – Biology Student (Revised June 25, 2008) (printed 8/26/2008) p. 1