Biological Molecules & Origin of Life

1. Biological Molecules & Origin of Life Introduction to important molecules which comprise the structure and function of all living organisms

2. Origin of the Earth • Universe formed 15 billion years ago (Big Bang) • Galaxies formed from stars, dust and gas • Earth formed 4.6 billion years ago

3. Origin of the Atmosphere • Suns energy stripped away 1st atmosphere • 2nd atmosphere formed from volcanic outgassing • Primitive atmosphere: CO2, water vapor, lesser amts of CO, N2, H2, HCl, and traces of NH3 and CH4(3.5 bya)

4. Origin of the Atmosphere • O2 came in 3.2-2 bya • Autotrophic Organisms: photosynthesis • Another environmental change • Result in evolution

5. Origin of Life Life began~ 3.5 bya Organic molecules (C H O N P S) swimming in shallow seas Stage 1: Abiotic synthesis of organic molecules such as proteins, amino acids and nucleotides

6. Origin of Life Stage 2: joining of small molecules (monomers) into large molecules

7. Origin of Life Stage 3:origin of self-replicating molecules that eventually made inheritance possible

8. Origin of Life Stage 4: packaging these molecules into pre-cells, droplets of molecules with membranes that maintained an internal chemistry

9. Origin of Life Thomas Huxley- Search for origin of life Bathybias heckali- primordial ooze Wyville Thompson: HMS Challenger (1872-1876) found it was actually diatomacous ooze reacting with seawater and ethyl alcohol

10. Origin of the Atmosphere • 0.5 billion years ago • Atmosphere O2 to 1% current • Compare to present: 78% N2, 21% O2, 0.04% CO2, + trace gasses • Relatively small, most single cell • Start of multicellularity • Increase in cell complexity

11. Origin of Life

12. Miller and Urey’s Experiment ELECTRICITY!!! Organic molecules like amino acids

13. Origin of Life • Produced: • 20 amino acids • Several sugars • Lipids • Purine and pyrimidine bases (found in DNA, RNA & ATP)

14. RNA world The first genetic material was probably self-replicating, catalytic RNA not DNA; In “RNA world”, RNA could have provided the template on which DNA was assembled Once DNA appeared “RNA world” gave way to “DNA world” The first organisms were not photosynthetic; they were probably heterotrophic

15. Protobionts, collections of abiotically produced molecules surrounded by a membrane-like structures • Liposomes can form when lipids or other organic molecules are added to water. • Have a bilayer • Can undergo osmosis • Can “reproduce”

16. Protocell (Protobiont) Fatty acid membrane with ribozymes inside

17. chemosynthetic bacteria (extremophiles) Chemosynthesis: 02 + 4H2S + C02 CH20 + 4S +3H20 Stromatolites (bacteria & cyanobacteria) Oldest fossils found in western Australia and southern Africa ~ 3.5 byo Photosynthesis: 6H2O + 6CO2 + nutrients + light energy C6H12O6 + 6O2

18. Stromatolites mostly cyano Stromatolites from Shark’s Bay Australia

19. Early prokaryotes may have arisen near hydrothermal vents Hydrothermal vents are rich in sulphur and iron-containing compounds needed for ATP synthesis. Temperatures can reach 120oC.

20. Hot springs in Yellowstone National Park – pigmented bacterial mats

21. Biological Compounds Categories: Carbohydrates Lipids Proteins Nucleic Acids

22. Characteristics of Biological Molecules to Consider Monomer • Subunits that serve as building blocks • Connected by condensation reactions (dehydration) Polymers • Covalent bonding occurs • Solubility in Water

23. Monomers and Polymers Monomer Polymer

24. Dehydration Synthesis Monomers H HO H HO H2O Polymer

25. Dehydration Synthesis C6H12O6 + C6H12O6C12H22O11 + H2O

26. Dehydration Synthesis H2O

27. Hydrolysis Monomers H2O H HO

28. Hydrolysis C12H22O11 + H2O C6H12O6 + C6H12O6

29. Hydrolysis

30. Characteristics of Carbohydrates Sugars, Starches & Others Principle Elements: C, H, & O From Photosynthesis Monomers: Monosaccharides Polymers: Polysaccharides Water Soluble

31. Function of Carbohydrates • Energy Metabolism • Structural Components • Cell-to-Cell Contacts and Recognition • Elimination of wastes (fiber) APT cell Helper-T cell

32. Monosaccharides Chemical Formulas C6H12O6 C6H12O6 From corn syrup

33. Monosaccharides Chemical Formulas C5H10O5 C5H10O4 deoxyribose

34. Disaccharides Lactose glucose + galactose Maltose glucose + glucose Sucrose glucose + fructose

35. Polysaccharides glycogen

36. Characteristics of Lipids • Oils, fats, waxes, phospholipids, steroids • Principle Elements: C, H, & O • Some With P & N • Water Insoluble

37. Functions of Lipids • Energy Storage • Protection & Cushioning of Body Organs • Structural Components of Membranes • Chemical Messengers (hormones)

38. Major Types of Lipids • Triglycerides (neutral fats) • Phospholipids • Sterols • Waxes

39. Triglycerides

40. Saturated Fats • Saturated with H+ • Most animal fats are saturated, ex. butter • Solid at room temp Glycerol Fatty Acids

41. Unsaturated Fats • Has one or more double bonds between • carbons • Most vegetable fats • Liquid at room temp

42. Phospholipids carbon hydrogen phosphorous oxygen Hydrophobic tails Hydrophilic head

43. Phospholipids Nonpolar hydrophobic tails (fatty acids) exposed to oil Polar hydrophilic heads exposed to water

44. Phospholipid Bilayer Outside of Cell Inside of Cell

45. Steroids Bacon grease cholesterol

47. Your Cholesterol Level • Cholesterol: <200 mg/dl • Triglycerides: blood fats, 30-175 mg/dl • HDL: Good cholesterol, > 35 mg/dl • LDL: Bad Cholesterol, <100 mg/dl • Chol/HDL ratio: < 4.5 indicates heart disease

48. Lowering Your Cholesterol Level • Eat healthy • Exercise • Lose wt. • Quit smoking • 1 glass of wine or beer • Medications (Lipitor)

49. Characteristics of Proteins • Principle Elements: C, H, O, & N • Monomers: Amino Acids • Polymers: Polypeptides or Proteins • Generally Water Soluble

50. Characteristics of Proteins Functional Groups of Amino Acids • Carboxylic Acid (-COOH) • Amine (-NH2) • R-Groups (variable - 20 different kinds)