1. DNA!
spooled
gene
chromosomes
chromatin
double helix

2. 1953
Wilkins Franklin
Watson Crick

3. • sugar-base-phosphate monomer
• polymer
• linear
• bases evenly spaced

4. • S/P/B monomer • polymer • linear • double molecule
• bases evenly spaced
• bases stacked
• base ratio: A=T C=G
• P on outside

5. Nucleotides are the monomer of nucleic acids
This component
varies

6. nucleotides creates a nucleic acid, a polymer
The chain of
nucleotides creates a nucleic acid, a polymer

7. The two helices are anti-parallel
sugar
covalent bond
nitrogen bases
phosphate
H-bond between them
N-base
The two helices are anti-parallel
constructed, read in opposite directions

8. DNA has 4 nucleotides
purines
pyrimidines

9. The base pair rule makes the two helices complementary
Adenine bonds to Thymine
H-bonds
Cytosine bonds to Guanine

10. DNA is replicated when cells reproduce (mitosis, meiosis)
• each old strand acts as a template for a new one
• the two stands each contain half of the original
Thus replication is semi-conservative

11. mistakes happen!
aka mutations

12. ‘spelling’ error - point mutation extra base inserted,
Possibilities:
‘spelling’ error - point mutation
extra base inserted,
one base skipped (deleted) frameshift effect
DNA sequence is ‘read’ in sets of 3 nucleotides, called codons
point mutations change one codon; frameshift changes all codons past the error
‘spelling’ error
deletion