生命的化學

1. 生命的化學 『從原子到宇宙』課程第十週 胡維平 國立中正大學化學暨生物化學系 11/19/2015

2. 生命的定義? • the condition that distinguishes organisms from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally. • life is a member of the class of phenomena that are open or continuous systems able to decrease their internal entropy at the expense of substances or free energy taken in from the environment and subsequently rejected in a degraded form. • At a higher level, living beings are thermodynamic systems that have an organized molecular structure.That is, life is matter that can reproduce itself and evolve as survival dictates. Hence, life is a self-sustained chemical system capable of undergoing Darwinian evolution.  2009, Prentice-Hall, Inc.

3. Life is complex chemical processes.  2009, Prentice-Hall, Inc.

5. 光合作用  2009, Prentice-Hall, Inc.

7. 呼吸作用

8. 生物分子

9. Amino Acids and Proteins • Proteins are polymers of -amino acids. • A condensation reaction between the amine end of one amino acid and the acid end of another produces a peptide bond.

10. 20 amino acids

11. Proteins • Hydrogen bonding in peptide chains causes coils and helices in the chain. • Kinking and folding of the coiled chain gives proteins a characteristic shape. • Most enzymes are proteins. • The shape of the active site complements the shape of the substrate on which the enzyme acts; hence, the “lock- and-key” model.  2009, Prentice-Hall, Inc.

13. Carbohydrates Simple sugars are polyhydroxy aldehydes or ketones. In solution, they form cyclic structures.

14. Lipid

15. Nucleic Acids Two of the building blocks of RNA and DNA are sugars (ribose or deoxyribose) and cyclic bases (adenine, guanine, cytosine, and thymine or uracil).

16. 1953Watson and Crick discovered the structure of DNA and solve the mystery of genetics  2009, Prentice-Hall, Inc.

17. DNA Replication  2009, Prentice-Hall, Inc.

18. Protein Synthesis  2009, Prentice-Hall, Inc.

19. Origin of Life Life on earth began ~35 byr ago. Where did the water come from? How were the biomolecules synthesized? How did the first life begin? Is the Universe fine-tuned for life?

20. 地球上的水從哪裡來?

21. From volcanoes? From comets?

22. Evolution of Life, Common Ancestor

23.  2009, Prentice-Hall, Inc.

24.  2009, Prentice-Hall, Inc.

25. Conducted in 1952by Stanley Miller, under the supervision of Harold Urey,

26. From RNA World to DNA World? RNA can store information and can act as an enzyme