1. DNA Structure

2. What is DNA?
A type of nucleic acid that stores genetic information in all organisms
Primary function of nucleic acids
To store and transmit genetic info
Provide instruction to build proteins
Monomer:
Nucleotides
*A DNA molecule is a chain of repeating units

3. DNA Nucleotides These repeating units are composed of:
A ring-shaped sugar (deoxyribose)
A phosphate group
1 phosphorus with 4 oxygens
A nitrogenous base

4. Nitrogenous Bases
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

5. James Watson & Francis Crick
Built the first DNA model using data from other scientists
Double Helix (Two strands of DNA wind around each other like a twisted ladder)
Rails – alternating deoxyribose and phosphate (aka sugar/phosphate backbone)
Rungs/Steps – base pairs

6. Adenine pairs with Thymine A=T Cytosine pairs with Guanine C=G

7. *Sugar-phosphate Backbone

9. Task To use the materials given to create a model of a DNA molecule
Model the sequence including complimentary base pairs:
Sequence 1: T A C G T A
Sequence 2: C G G T A C
Sequence 3: A C G C T T
Sequence 4: G A C C T A

10. Question
In a sample of yeast DNA, 31.5% of the bases are Adenine (A). Predict the amounts of T, C and G.