1. 2.6: Structure of DNA and RNA

2. A ‘cheeky’ genetics experiment
Watson & Crick
In 1962 Watson & Crick shared the Nobel Prize for Physiology or Medicine.
Read pg. 109/11
A ‘cheeky’ genetics experiment
Go to moodle and download ‘cheeky’ genetics experiment to isolate your own DNA. Follow all instructions carefully.

3. DNA
Follow the instructions to make your very own origami DNA molecule!

4. The DNA nucleotide Covalent bonds  strong backbone for each strand.
Pentose sugar
Phosphate group (acidic, negatively charged)
Base (contains nitrogen, can have either one or two rings)
You must be able to draw this simple structure, using circles, pentagon & square.
Covalent bonds  strong backbone for each strand.
Hydrogen bonds form between bases.

5. The Strands P S P DNA is made up of two strands.
At one end of each strand there is a phosphate group attached to the carbon atom number 5 of the deoxyribose (this is the 5' terminal)
At the other end of each strand is a hydroxyl group attached to the carbon atom number 3 of the deoxyribose (this is the 3' terminal). P 5 O S 4 1 3 2 P

6. The strands run in opposite directions and so we say that they are antiparallel.
One strand runs in a 5'-3' direction and the other runs in a 3'-5' direction. 
The bases of each strand link together via hydrogen bonds.

7. Adenine and Guanine are purines as they have two rings in their molecular structure.

8. Thymine and Cytosine are pyrimidines as they only have one ring in their molecular structure.

9. Rules….
A purine will link with a pyrimidine.
Adenine and thymine link together by forming two hydrogen bonds.
Guanine and cytosine link together by forming 3 hydrogen bonds.

11. The differences with RNA nucleotides
DNA
RNA
Deoxyribose sugar (one less oxygen than ribose)
Ribose sugar (one more oxygen than deoxyribose)
Double stranded
Single stranded
Four bases are: adenine, cytosine, guanine and thymine
Four bases are: adenine, cytosine, guanine and uracil.