1. Homework #1 is posted and due 9/17 Bonus #1 is posted and due 10/24 Discussions start M 9/10

2. Fig 7.5 +8.2 This subtle difference in structure has profound effects.

3. Fig 7.8 Connect nucleotides by covalent bond = strand (notice 5’-3’ bond)

4. Fig 8.11 DNA stores information, but does not do anything. The information must be expressed to be useful.

5. Fig 8.11 Where did this system come from?

6. Was RNA the first biological molecule? The RNA World pg 312

7. Living organisms must fit all of the following criteria: (modified from Campbell “Biology”) 1. They must have organization. 2. They must have metabolism. 3. They must respond to the environment. 4. They must be able to reproduce themselves.

8. C G A U* RNA structure Fig 8.2

9. RNA can form base pairs within single stranded molecule Fig 8.10+9.12

10. RNA can form complex 3-D structures Ribosomes (rRNA) have enzymatic activity: Enzymatic RNA=ribozyme Fig 9.12

11. pg 223 Some RNA molecules have catalytic activities

12. Living organisms must fit all of the following criteria: (modified from Campbell “Biology”) 1. They must have organization. 2. They must have metabolism. 3. They must respond to the environment. 4. They must be able to reproduce themselves.

13. RNA can (theoretically) be replicated using complementary bases

14. Experimental determination of RNA’s ability to self-ligate… A step towards self- replication from Freeman’s “Biological Science” (2002) chapter 3

15. Q: Can RNA self- ligate? Hypos: Yes. No. from Freeman’s “Biological Science” (2002) chapter 3

17. RNA’s added in aqueous solution Without tag, flow thru Some, with tag, bind to column Column Chromatography

19. Overall RNA self-ligation improves by selection

20. Theoretical evolution of self-replicating RNA

21. Hypothetical Origin of Life pg 214

22. Protein DNA is used to produce RNA and/or proteins, but not all genes are expressed at the same time or in the same cells. How do cells control which genes are expressed?

23. Is there anybody out there? Cells and organisms must monitor and respond to the environment.

27. Stimulus Signal Transduction Stimulus Perception (by receptor) Effector Response Effector… Effector External Internal