1. 2.6 Structure of DNA and RNA
Understanding:
The nucleic acids and DNA and RNA are polymers of nucleotides
DNA differs from RNA in the number of strands normally present, the base composition and type of pentose
DNA is a double helix made of two antiparallel strands of nucleotides linked by hydrogen bonding between complementary base pairs
Applications:
Crick and Watson’s elucidation of the structure of DNA using model-making
Nature of science:
Using models as representation of the real world: Crick and Watson used model-making to discover the structure of DNA
Skills:
Drawing simple diagrams of the structure of single nucleotides and of DNA and RNA, using circles, pentagons and rectangles to represent phosphates, pentoses and bases

2. Polymer Individual unit called a nucleotide DNA and RNA
Nucleic Acids
Polymer
Individual unit called a nucleotide
DNA and RNA

3. Nucleotide Structure 3 components: Pentose sugar Phosphate
base
Stay the same
Changes
Contains nitrogen & carbon
Pentose sugar
(5 Carbon atoms)
3 components:
Pentose sugar
(ribose in DNA and RNA)
Phosphate
Organic base
(always contains nitrogen)

5. DNA or RNA?
DNA
RNA
Sugar is deoxyribose Sugar is ribose Deoxyribonucleic acid Ribonucleic acid Contains one less oxygen on ribose Contains one more oxygen on ribose Single stranded Double stranded (double helix) Contains uracil as a base Contains thymine as a base

6. DNA or RNA? DNA RNA Sugar is deoxyribose Deoxyribonucleic acid
Contains one less oxygen on ribose
Double stranded (double helix)
Contains thymine as a base
Sugar is ribose
Ribonucleic acid
Contains one more oxygen on ribose
Single stranded
Contains uracil as a base

7. Adenine Thymine Cytosine Guanine
Bases
Adenine
Thymine
Cytosine
Guanine

8. *Purines always pair with pyrimidines*
4 Bases
Purines –
Double ringed structure
Pyrimidines –
Single ringed structure
*Purines always pair with pyrimidines*

9. C only likes G and A only likes T.
T is green and A is orange, C is red and G is blue.
What would the colour order of the following sequence be?
CATTGTAC
What would be the opposite?

10. CATTGTAC
GTAACATG

11. Bondings The base and sugar join with a: glycosidic bond
The phosphate and sugar join with an:
ester bond
Both require a condensation reaction to occur 

12. 2 condensation reactions occur in the formation of a nucleotide:
Phosphate
2 condensation reactions occur in the formation of a nucleotide: H
Ester bond OH
Glycosidic
bond OH H
Base
Sugar

13. 5’
3 hydrogen bonds 3’ C G
0.34nm A T 3’
2 hydrogen bonds 5’
2nm

14. Tell me… 4 names of bases in DNA 3 components of a nucleotide
2 types of bonds in a nucleotide
1 place where a condensation reaction occurs
1 difference between purine and pyrimidine bases

15. It took two attempts for them to be successful
DNA models
Model making was a key part in Crick and Watson’s discovery of the structure of DNA
It took two attempts for them to be successful

16. DNA models Who were Crick and Watson? What did they discover?
What did their first model look like?
What did their second model look like?
What was Rosalind Franklin’s role?
What were the issues with their first model?

17. DNA bracelets Follow the sheet to make a bracelet
What does each part represent?
What are the good parts and bad parts of your model?
How could it be improved?