1. Biology 107 Macromolecules III September 10, 2002

3. Protein “Partners” (Chaperones) Influence Folding

4. Macromolecules III Student Objectives:As a result of this lecture and the assigned reading, you should understand the following: 1.Nucleic Acids are polymers of nucleotides. There are two types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). 2.Nucleic acids function in information coding, storage and transfer. DNA does not directly control protein synthesis, instead it works through intermediates, RNA molecules.

5. Macromolecules III 3.Each nucleotide monomer has three (3) parts: five carbon sugar phosphate group nitrogenous base Nucleic acids contain one of two 5-carbon sugars, either deoxyribose (in DNA) or ribose (in RNA). Linked to the one end of the sugar is a phosphate group, and linked to the other end of the pentose is one of the nitrogenous bases. DNA has the nitrogenous bases adenine (A), guanine (G), thymine (T), and cytosine (C). RNA has A, G, C and uracil (U) (instead of thymine).

6. Macromolecules III 4.A nucleic acid polymer, a polynucleotide, forms from monomers covalently linked by dehydration synthesis. The phosphate group of one nucleotide bonds to the sugar of the next nucleotide, with the result a repeating sugar-phosphate backbone. 5.RNA is normally a single polynucleotide strand, while DNA is a double-stranded molecule. 6.Nucleic acids form complementary base pairs stabilized by hydrogen bonds, with guanine pairing with cytosine and adenine pairing with thymine or uracil.

7. Functions of Nucleic Acids Information coding, storage, and transfer Synthesis of other nucleic acids or proteins Central Dogma DNA↓RNA↓Protein

8. Structure of Nucleotides

9. Pentose sugar Phosphate group Nitrogenous base

10. Nitrogenous Bases

11. DNA Is Normally Double-Stranded Each strand has polarity (5’ and 3’ ends). In double-stranded DNA each strand is oriented “anti-parallel” to the other strand. The strands are normally held together by hydrogen bonds. The optimal hydrogen bonding is when A bonds with T and G bonds with C.

12. Base Pairing in DNA G/C pairs have three hydrogen bonds A/T pairs have two hydrogen bonds

13. Double Helix

15. ATP Is a Nucleotide

16. ATP Structure and Hydrolysis