Functions of DNA

DNA must do three important things:

1. Carry information from one generation to the next

2. Put that information to work– (Determine the heritable

characteristics of organisms)

3. Be easily copied– (All a cell’s information has to

duplicated every time a cell divides)

DNA Structure

(DNA is a VERY long molecule) Made up of units (monomers)

called nucleotides 3 parts to a nucleotide:

1. 5-carbon sugar: deoxyribosedeoxyribose

2. Phosphate group

3. A nitrogen base

Nitrogen Bases

Adenine (A) Guanine (G) Cytosine (C) Thymine (T)

Cytosine and Thymine are PYRIMIDINES Adenine and Guanine are PURINES

“Backbone” of DNA is formed by the sugar and phosphate groups

Bases stick out sideways from the “backbone”

Nucleotides can be joined together in any order (ANY sequence is

possible!!)

DNA Structure

Double Helix

Two spiral structures, wrapped around each other