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2. Nucleic Acids TWO MAIN TYPES DNA- Deoxyribonucleic Acid RNA- Ribonucleic Acid

3. DNA is present in the nucleus of all cells in all living organisms. It is exactly the same in every cell of that organism DNA controls all the chemical changes which take place in cells The kind of cell which is formed, (muscle, blood, nerve etc) is controlled by DNA The kind of organism which is produced (buttercup,giraffe, herring, human etc) is controlled by DNA 2

4. DNA & RNA are very large molecules made up of a long chain of monomers The monomers are called nucleotides Each nucleotide is made up of 1)a sugar called Deoxyribose/Ribose 2)a phosphate group -PO 4 and 3)A nitrogen base 3

5. Ribose is a five carbon monosacharride (sugar) found only in RNA Deoxyribose is a five carbon sugar only found in DNA Both molecules may be represented by the symbol Nucleotide Sugars: Ribose & Deoxyribose 4

6. The four Nitrogen bases in DNA are Adenine(A) Thymine(T) Cytosine(C) Guanine (G) The Nitrogen bases 5

7. NITROGEN BASES

8. The deoxyribose,the phosphateand one of the bases adenine deoxyribose PO 4 Combine to form a nucleotide Nucleotides 6

9. NUCLEOTIDES

10. A molecule of DNA is formed by millions of nucleotides joined together in a long chain The nucleotides are attached by a covalent bond between the sugar and the phosphate. PO 4 sugar-phosphate backbone + bases Joined nucleotides 7

11. DNA consists of a double strand of nucleotides joined together by a hydrogen bond between the Nitrogen bases In what type of molecules do hydrogen bonds form? Which is easier to break a covalent bond or a hydrogen bond? 8

12. PO 4 2-stranded DNA 9

13. The bases always pair up in the same way Adenine forms a bond with Thymine and Cytosine bonds with Guanine Bonding 1 10 AdenineThymine Cytosine Guanine

14. PO 4 thymine PO 4 adenine cytosine PO 4 guanine Bonding 2 11

15. PO 4 Pairing up 12

16. The paired strands are coiled into a spiral called A DOUBLE HELIX 13

17. sugar-phosphate chain bases THE DOUBLE HELIX 14

18. DNA vs. RNA 1)Contains the Sugar Deoxyribose 2)Two Strands (Double Stranded) 3)Contains the Nitrogen base THYMINE 4)Found only in the nucleus 5) Only type is DNA Function: Instructions to make proteins, contains the genetic code. 1)Contains the sugar Ribose 2)One strand 3)Contains the Nitrogen Base URACIL 4)Found in the nucleus and cytoplasm 5)Types include rRNA, tRNA and mRNA Function: Runs protein synthesis and is a copy of DNA DNARNA

19. DNA VS RNA