Carbon: The backbone of life

1. Carbon: The backbone of life

2. Key concepts • Organic chemistry is the study of carbon compounds • Carbon atoms can form diverse molecules by bonding to four other atoms • A small number of chemical groups are key to the functioning of biological molecules

3. Organic chemistry is the study of carbon compounds The term “organic” chemistry came from the misconception that carbon-based compounds were always connected to life

4. Organic chemistry is the study of carbon compounds The term “organic” chemistry came from the misconception that carbon-based compounds were always connected to life Exception:

5. “Atmosphere” CH4 Water vapor Electrode H2 NH3 Condenser Cooled water containing organic molecules Cold water H2O “sea” Sample for chemical analysis Organic chemistry is the study of carbon compounds Exception:

6. Organic chemistry is the study of carbon compounds • It mostly involves CHOPNS • With few elements it is possible to create a diversity of molecules ….because of the special properties of carbon

7. Carbon atoms can form diverse molecules by bonding to four other atoms

8. Carbon atoms can form diverse molecules by bonding to four other atoms The key to an atom’s chemical characteristics is its electron configuration Carbon’s valence shell is half-full…or is it half-empty?

9. Carbon atoms can form diverse molecules by bonding to four other atoms Carbon usually completes its valence shell by sharing electrons with other atoms in covalent bonds • These bonds can be single • Tetrahedral shape

10. Carbon atoms can form diverse molecules by bonding to four other atoms Carbon usually completes its valence shell by sharing electrons with other atoms in covalent bonds • Carbon can also form double bonds • Forms when two electrons are shared between two atoms • Forms a flat molecule

11. Carbon atoms can form diverse molecules by bonding to four other atoms Carbon usually completes its valence shell by sharing electrons with other atoms in covalent bonds

12. Carbon atoms can form diverse molecules by bonding to four other atoms Carbon usually completes its valence shell by sharing electrons with other atoms in covalent bonds Would biological molecules be diverse if life was hydrogen-based?

13. Helium 2He Hydrogen 1H First shell Lithium 3Li Beryllium 4Be Fluorine 9F Boron 5B Nitrogen 7N Neon 10Ne Carbon 6C Oxygen 8O Second shell Chlorine 17Cl Sodium 11Na Aluminum 13Al Silicon 14Si Argon 18Ar Magnesium 12Mg Phosphorus 15P Sulfur 16S Third shell Carbon atoms can form diverse molecules by bonding to four other atoms

14. Carbon atoms can form diverse molecules by bonding to four other atoms Silicon-based life!!

15. Molecular diversity arising from carbon skeleton variation

16. Ethane Propane 1-Butene 2-Butene (a) Length (c) Double bonds Butane 2-Methylpropane (commonly called isobutane) Cyclohexane Benzene (b) Branching (d) Rings Molecular diversity arising from carbon skeleton variation Sources of diversity: • Chain length

17. Ethane Propane 1-Butene 2-Butene (a) Length (c) Double bonds Butane 2-Methylpropane (commonly called isobutane) Cyclohexane Benzene (b) Branching (d) Rings Molecular diversity arising from carbon skeleton variation Sources of diversity: • Chain length Hydrocarbons!

18. Ethane Propane 1-Butene 2-Butene (a) Length (c) Double bonds Butane 2-Methylpropane (commonly called isobutane) Cyclohexane Benzene (b) Branching (d) Rings Molecular diversity arising from carbon skeleton variation Sources of diversity: • Chain length Hydrocarbons! Polar or non-polar?

19. Ethane Propane 1-Butene 2-Butene (a) Length (c) Double bonds Butane 2-Methylpropane (commonly called isobutane) Cyclohexane Benzene (b) Branching (d) Rings Molecular diversity arising from carbon skeleton variation Sources of diversity: • Chain length • Branching

20. Ethane Propane 1-Butene 2-Butene (a) Length (c) Double bonds Butane 2-Methylpropane (commonly called isobutane) Cyclohexane Benzene (b) Branching (d) Rings Molecular diversity arising from carbon skeleton variation Sources of diversity: • Chain length • Branching • Double bonds

21. Molecular diversity arising from carbon skeleton variation Sources of diversity: • Chain length • Branching • Double bonds

22. Molecular diversity arising from carbon skeleton variation Sources of diversity: • Chain length • Branching • Double bonds • Ring formation

23. Molecular diversity arising from carbon skeleton variation

24. Other forms of diversity

25. Other forms of diversity Isomers-compounds that have the same numbers of atoms of the same elements, but different structures (hence different properties)

26. Other forms of diversity Three types of isomers • Structural • Geometric • Enantiomers

27. Other forms of diversity Three types of isomers • Structural isomers differ in the arrangement of their atoms or in the arrangement of double bonds C4H8

28. Ethane Propane 1-Butene 2-Butene (a) Length (c) Double bonds Butane 2-Methylpropane (commonly called isobutane) Cyclohexane Benzene (b) Branching (d) Rings Other forms of diversity Three types of isomers • Structural isomers differ in the arrangement of their atoms or in the arrangement of double bonds

29. Other forms of diversity Three types of isomers • Structural isomers differ in the arrangement of their atoms or in the arrangement of double bonds C4H10

30. Ethane Propane 1-Butene 2-Butene (a) Length (c) Double bonds Butane 2-Methylpropane (commonly called isobutane) Cyclohexane Benzene (b) Branching (d) Rings Other forms of diversity Three types of isomers • Structural isomers differ in the arrangement of their atoms or in the presence or absence of double bonds

31. Other forms of diversity Three types of isomers • Structural • Geometric isomers have the same covalent partnerships, but differ in their spatial arrangement (related to inflexibility of double bonds)

32. Other forms of diversity Three types of isomers • Structural • Geometric isomers have the same covalent partnerships, but differ in their spatial arrangement (related to inflexibility of double bonds) i.e. cis v. trans fats

33. Other forms of diversity Three types of isomers • Structural • Geometric • Enantiomers are isomers that are mirror images of each other

34. A small number of chemical functional groups are key to the function of biological molecules

35. A small number of chemical functional groups are key to the function of biological molecules • Properties of the molecule will also depend on the molecular components attached to the carbon skeleton • Functional groups can replace H • These groups participate in chemical reactions and change the molecular shape

36. A small number of chemical functional groups are key to the function of biological molecules These differences in functional group in these two hormones drastically impact their function.

37. Can you identify any of the common functional groups on the following biological molecules?

38. Can you identify any of the common functional groups on the following biological molecules?

39. Adhesion Water-conducting cells Direction of water movement Cohesion Can you identify any of the common functional groups on the following biological molecules?

40. Can you identify any of the common functional groups on the following biological molecules?

41. Can you identify any of the common functional groups on the following biological molecules?

42. Key concepts • Organic chemistry is the study of carbon compounds • Carbon atoms can form diverse molecules by bonding to four other atoms • A small number of chemical groups are key to the functioning of biological molecules