- Sugar is either ribose or deoxyribose
- Carbons in sugar are labeled from 1’ to 5’
- Base is attached to 1’ carbon
- Phosphate is attached to 5’ carbon
- Next phosphate is attached to 3’ carbon
- Can only add to the 3’ carbon
- Dehydration synthesis creates phosphodiester linkages
- One chain has 5’ at top, other has 3’ at top
\
5' | _O_
| ,' `.
|' `.
4' \ / 1'
\ /
\_____/
3' 2'
- Base A links to T, G links to C
- A, G are purine
- C, T are pyrmidine
- Purine has two rings, pyrimidine has one
5' 3'
| A - T |
|———————|
| G - C |
|———————|
| T - A |
|———————|
| C - G |
3' 5'
