1. 1 NUCLEIC ACIDS

2. 2 Things to Consider What might be meant by the statement “we are what we are because of our DNA”? What is required to transform musical notes into a melody that listeners can enjoy or a blueprint into a house where people can live? Why is it so important to understand the structure of DNA?

3. 3 Nucleic Acids DNA was first isolated by Swiss Biochemist Johann Friedrich Miescher in 1869 Because DNA molecules are acidic and found in the nucleus, Miescher called them nucleic acids Before scientists could fully explain their function, they needed to clearly understand their structure

4. 4 WHAT IS IN DNA? DNA is made of repeating NUCLEOTIDES A DNA nucleotide consists of a five carbon sugar called DEOXYRIBOSE, a PHOSPHATE group and a NITROGEN BASE

5. 5 NUCLEOTIDE!

6. 6 NUCLEOTIDE BASES

7. 7 Nucleic Acids Store hereditary information Contain information for making all the body’s proteins Two types exist --- DNA & RNA

8. 8 Nucleic Acids Originally isolated from nuclei Two types Deoxyribonucleic acid (DNA) Passed from generation to generation Constitute genome/chromosomes/genes Contains instructions for making proteins Ribonucleic acid (RNA) Function in the synthesis of proteins coded by DNA Several distinct types Make up the genomes of some viruses Originally isolated from nuclei Two types Deoxyribonucleic acid (DNA) Passed from generation to generation Constitute genome/chromosomes/genes Contains instructions for making proteins Ribonucleic acid (RNA) Function in the synthesis of proteins coded by DNA Several distinct types Make up the genomes of some viruses

9. 9 STRUCTURE OF DNA Watson (Biologist) & Crick (Physicist) solved the puzzle using scale models of nucleotides that were arranged in a spiral. Their model looked like a “twisted ladder” and they called it a DOUBLE HELIX The sides of the ladder are made of alternating sugar molecules and phosphate molecules The rungs of the ladder are made of paired nitrogen bases paired by hydrogen bonds and are combined in a particular way. A-T and C-G (adenine pairs with thymine) and (cytosine pairs with guanine)

10. 10 Watson & Crick

11. 11

12. 12 Nucleotide Monomers Form long chains - DNA Backbone Nucleotide Bases DNA strand Nucleotides are joined by sugars & phosphates on the side

13. 13 Nucleic Acids

14. 14

15. 15 STRUCTURE OF DNA

16. 16 PRACTICE BUILDING SOME DNA! Journey into DNA

17. 17

18. 18 CHECK FOR UNDERSTANDING!! 1.What molecules compose a nucleotide? Deoxyribose sugar, phosphate, and a nitrogen base

19. 19 2. Describe the shape of a DNA molecule. Long chain of nucleotides arranged in a spiral called a DOUBLE HELIX CHECK FOR UNDERSTANDING!!

20. 20 Did you know that a series of 3 nucleotides on a DNA molecule, called a triplet, codes for one amino acid (building block for proteins)? So, the sequences of bases in DNA make up the codes for the specific amino acids in a protein chain!!!! CHECK FOR UNDERSTANDING!!

21. 21 Q3. What effect does base sequence in a DNA molecule have on a cell? It determines which protein will be formed! CHECK FOR UNDERSTANDING!!

22. 22 REPLICATION OF DNA How is DNA copied? Replication – DNA is the only molecule that is capable of duplicating itself Weakening of Hydrogen bonds between nitrogen bases allow the DNA to “unzip” A series of enzymes, called polymerases, fuse free floating nucleotides to the complementary parent strands -Semiconservative replication

23. 23 Replication as a process Double-stranded DNA unwinds. The junction of the unwound molecules is a replication fork. A new strand is formed by pairing complementary bases with the old strand. Two molecules are made. Each has one new and one old DNA strand.

24. 24 Enzymes in DNA replication Helicase unwinds parental double helix Binding proteins stabilise separate strands DNA polymerase binds nucleotides to form new strands Ligase joins Okazaki fragments and seals other nicks in sugar- phosphate backbone Primase adds short primer to template strand DNA polymerase I (Exonuclease) removes RNA primer and inserts the correct bases

25. 25 P P P P P P P P PP CH 2 OH O O O Base CH 2 OH O O O Base 5' end of strand 3' end of strand 3' 5' 3' H20H20 + Synthesis reaction DNA SYNTHESIS REACTION products

26. 26 BioCoach Activity http://www.phschool.com/science/biology_place/biocoa ch/dnarep/nucleotide.html

27. 27 WHAT is RNA? – Ribonucleic Acid Ribose sugar has an extra –OH or hydroxyl group It has the base uracil (U) instead of thymine (T) Nitrogenous base (A,G,C, or U) Sugar (ribose) Phosphate group Uracil

28. 28 Macromolecules

29. 29 Macromolecules