1. Nucleotides
Starter
What is DNA ?
Where will you find DNA in a cell?

2. Nucleotides
Aims:
What are the components of DNA?
How are these components arranged within the DNA double helix?
What is the function of DNA?

3. Answer the questions on your worksheet.
Watch the video.
Answer the questions on your worksheet.

4. DNA (and RNA) is a nucleic acid
It is made from lots of nucleotide monomers joined together by condensation reactions to form a polynucleotide.
Its function is to act as an information carrying molecule that determines the structure of proteins, including enzymes.

5. Look at all this Nitrogen!
Nucleotide
Four types
Look at all this Nitrogen!
Adenine
Guanine
Cytosine
Three parts
Thymine

6. Nucleotide
Four types
Adenine
Guanine
Purines have two rings
Cytosine
Three parts
Thymine

7. Pyrimidines have one ring
Nucleotide
Four types
Adenine
Guanine
Pyrimidines have one ring
Cytosine
Three parts
Thymine

8. Nucleotide
Three parts
Deoxyribose sugar

9. Phosphate Group
Nucleotide
Three parts

11. Sides are phosphates and sugars (deoxyribose)
Rungs are bases
Sides are phosphates and sugars (deoxyribose)

12. The rungs (bases) are held together by hydrogen bonds
Rungs are bases
The rungs (bases) are held together by hydrogen bonds
Sides are phosphates and sugars (deoxyribose)

13. The rungs (bases) are held together by hydrogen bonds
This means that when DNA needs to be copied, the two strands can be easily split apart

14. The rungs (bases) are held together by hydrogen bonds
This means that when DNA needs to be copied, the two strands can be easily split apart

15. When the molecules twist into a helix, they are held in a stable structure, by the formation of hydrogen bonds between each coil of the helix.

16. What about the ratio in different species?
10 bases for each complete turn (3.4nm)
What is the relationship between the quantities adenine and thymine in DNA?
What is the relationship between the quantities of guanine and cytosine in DNA?
What about the ratio in different species?

17. Nucleotides
TASK:
Complete the questions on your sheet. The notes in your Unit 2 booklet are up to you to do in your own time.
All questions to be completed for homework.

18. THE END