1. Nucleic Acid Structure DNA Replication Structure of DNA and RNA Duplication of DNA

2. DNA RNA Protein Information Flow From DNA transcription translation replication (S phase) (G1 and G2 phases) phases)

3. Macromolecules: Polymers Made of Repeating Monomers Macromolecule Monomer Unit CarbohydratesSugars Lipids Fatty acids Proteins Amino acids Nucleic Acids Nucleotides

4. DNA and RNA Structure DNA DNA RNA RNA Primary Structure Chain of nucleotides Secondary Structure Double helix Single folded chain

5. Three Parts of Nucleotide Structure Nitrogenous Base (1 of 5) CH 2 HH Deoxyribose or Ribose OO HH OHOHHH HH HH OH HOP O O 5-Carbon Sugar Phosphate Group NN HCHC NN CC CC CC CHCH NN NN NH 2

6. DNA and RNA Structure DNA RNA RNA Purine bases Adenine (A) Guanine (G) Adenine (A) Guanine (G) Pyrimidine bases Cytosine (C) Thymine (T) Cytosine (C) Uracil (U) 5-carbon sugar deoxyriboseribose Phosphate PO 4 PO 4 OHOH OHH

7. Clarification Pause Turn to a partner and identify the differences between DNA and RNA structure

8. Nucleotide Chain Nucleotides are joined together by dehydration synthesis Nucleotides are joined together by dehydration synthesis The phosphate of one nucleotide is joined to sugar of next nucleotide, forming a “sugar-phosphate backbone” The phosphate of one nucleotide is joined to sugar of next nucleotide, forming a “sugar-phosphate backbone”

9. DNA Structure Two nucleotide chainsTwo nucleotide chains In opposite orientationsIn opposite orientations Held together by hydrogen bondsHeld together by hydrogen bonds Twisted into a helixTwisted into a helix

10. Chemical Bonding Covalent Bond Strong Atoms Share Electrons Formation of Nucleotides and Chains HydrogenBondWeak Atoms “Share” a Hydrogen Pairing of Nucleotide Bases in Opposite Chains

11. T A CG

12. DNA Secondary Structure The Double Helix Two polynucleotide chains are wound togetherTwo polynucleotide chains are wound together Bases are located inside the helixBases are located inside the helix Sugar-phosphate groups are on the outside as a “backbone”Sugar-phosphate groups are on the outside as a “backbone” Bases are arranged like rungs on a ladder, perpendicular to the “backbone”Bases are arranged like rungs on a ladder, perpendicular to the “backbone” 10 base pairs per turn of the helix10 base pairs per turn of the helix

13. DNA Secondary Structure The Double Helix Hydrogen bonding between bases holds the chains togetherHydrogen bonding between bases holds the chains together Base pairing rules: A pairs with T G pairs with C Polynucleotide chains have opposite polarity Polynucleotide chains have opposite polarity One is 5’  3’ Other is 3’  5’ One is 5’  3’ Other is 3’  5’ 3’ 5’ 3’ 5’

14. Applying Your Knowledge In the DNA double helix, which base is paired with adenine? 1.Adenine 2.Cytosine 3.Guanine 4.Thymine 5.Uracil

15. DNA Replication

16. DNA replication is semiconservative. Each strand is used as a template to produce a new strand. AGCTAGCTAGCT TCGATCGATCGA TCGATCGATCGA new AGCTAGCTAGCT new AGCTAGCTAGCT  AGCTAGCTAGCT old TCGATCGATCGA  TCGATCGATCGA old

17. DNA Replication DNA replication requires 1. Enzymes, including DNA polymerase that adds nucleotides in a 5’  3’ direction. 1. Enzymes, including DNA polymerase that adds nucleotides in a 5’  3’ direction. 2. nucleotides 2. nucleotides 3. energy 3. energy 5’—A G C T — 3’ 3’—T C G A — 5’ A — 5’G C G 3’— T CT— 3’5’— A

18. Outcome of DNA Replication

19. Applying Your Knowledge After DNA replication, what is the composition of the new double-helical molecules? 1.Two new chains 2.Two old chains 3.One old and one new chain 4.One helix has two new chains and one has two old chains 5.None of these is correct.