Ch 2: Molecular Interactions

1. Ch 2: Molecular Interactions Or, Chemistry class in one lecture! Key Concepts • Elements, Atoms, Isotopes etc. • Chemical formulas, Chemical bonds • Solutions, Concentrations, pH • Organic Chemistry / Biochemistry

2. Element = Building block of matter • Periodic Table of the Elements • In human: 11 major essential elementsC, O, H, Na, Se, P, Mg, Mn, K, Ca, Fe = trace elements • Organic Chemistry = Chemistry of Carbon

3. Structure of Atoms(AKA elements) • Some Terminology: • Atomic Number • Atomic mass • Ion • Isotope

4. Isotopes = Atoms of an element that have different numbers of neutrons. Same Atomic Number, variable Atomic Mass Much rarer Most common Heavy water = ?

5. Some isotopes are unstable: Radioisotopes 3 types of radiation: •  radiation – protons and neutrons • Generally not dangerous to life unless inhaled or ingested • Commonly emitted from radioactive substances like uranium • Does not travel far

6. Some isotopes are unstable: Radioisotopes •  radiation - electrons • Relatively harmless • Medium penetrating power • Can mutate DNA if struck • Used to kill cancer cells

7. Some isotopes are unstable: Radioisotopes • -Radiation • High energy waves, not particles • Gamma Radiation can penetrate thick material • Since Gamma Radiation is more penetrating it can cause the most damage to the human body • Gamma knife • Used for benign or malignant tumors of the brain

8. Alpha radiation consists of helium-4nucleus and is readily stopped by a sheet of paper. Beta radiation, consisting of electrons, is halted by an aluminium plate. Gamma radiation is eventually absorbed as it penetrates a dense material. Lead is good at absorbing gamma radiation, due to its density.

9. http://www.youtube.com/watch?v=3u_8frR0IpE

10. http://www.youtube.com/watch?v=rvAJ_u3Q0Hw&feature=related • http://www.youtube.com/watch?v=_W_lLhBt8Vg

11. Nuclear Medicine: use of radioisotopes in diagnosis & treatment of disease. 127I is “normal” iodine 131I has 4 extra neutrons  and  radiation Medical Imaging ? Treatment?

12. The Chemistry of Life • Elements = Atoms • Nucleus • Protons • Neutrons • Orbit • Electrons

13. Atoms Atoms must be neutral Atoms/molecules that are stable will not bond with other atoms/molecules. • Atomic number • The number of protons, usually also equals the number of electrons.

16. Electron Bonding • Outermost shell contains all pairs of electrons • Stable • Outermost shell contains at least one unpaired electron • Unstable • Lose, gain or share electrons to become stable • An atom is most stable when each electron is paired!

17. Chemical Bonds • Ionic: electrons pulled from one atom to another: Na+ and Cl- • Covalent: electrons shared equally • Hydrogen: weak attraction • -Causes surface tension in water.

18. Chemical Bonds • Ions • More (or less) electrons than protons • Ionic Bonds • Anions • Negative • Cations • Positive • Ions are often called electrolytes!

19. Ionic Bonds • Give away or receive electrons to create ions and for each ion to become more stable • Ions of opposite charge bind with each other to form an ionic bond • An ionic bond typically includes a metal • NaCl

20. Ionic Bonding

21. Important Ions in Physiology cations anions

22. Chemical Bonds • Covalent • Polar • Non-polar

23. Covalent Bonds • Strong bonds that occur when two atoms share electrons in order to become more stable

24. Covalent Bonds • Non-polar Covalent Bonds • If the electrons are shared equally between atoms • Polar Covalent Bonds • If electrons spend more time around one atom than the other • Molecules develop regions of partial positive and negative charges

25. Covalent Bonds

26. http://www.youtube.com/watch?v=QqjcCvzWwww

27. Covalent bond: Water The electrons are shared equally If two electrons are shared, that is a “double bond.”

28. Chemical Bonds • Hydrogen Bonds • Surface tension • Attractive force between water molecules that causes water to form spherical droplets • Weak attractive force between hydrogen and oxygen, nitrogen or fluorine atoms • Quickly forms and quickly breaks

29. Reactions • Types of Reactions • Synthesis Reaction--Anabolic • A + B C • Decomposition Reaction--Catabolic • AB A + B • Exchange Reaction • AB + C AC + B • Oxidation-Reduction Reactions (REDOX)

30. Chemical Reactions • Reactants form Products • First Type of Reaction • Anabolic or Synthesis Reaction

32. Chemical Reactions • Decomposition Reaction • Catabolic

34. Acid Base Reactions Acids • The concentration Hydrogen ions free in solution • Protons • H+ • Bases • Are proton acceptors • Bind with hydrogen ions • Hydroxyl ion = OH- • Bicarbonate ion = HCO3-

36. Buffers • Buffers resist abrupt and large swings in the pH of body fluids. • To resist large changes in pH, the body releases hydrogen ions when the pH rises and binds hydrogen ions with bicarbonate ions when the pH drops. • Blood pH = 7.35 – 7.45

37. Buffers • CO2 + H2O H2CO3 H++ HCO3-

38. End of Inorganic Chemistry

39. BIOMOLECULES • Carbohydrates • Fats • Proteins

40. Organic Compounds • Carbohydrates • A group that includes things like table sugars and starches. • Includes Simple and Complex groups

41. Simple Carbohydrates • Simple • Monosaccharides • Fructose • Glucose • Disaccharides • Sucrose • Lactose

42. Monosaccharides

43. Disaccharides

44. Polysaccharide

45. OrganicCompounds • Complex Carbohydrates • Polysaccharides are long branching chains of simple sugars, specifically glucose. • Starch is a storage carbohydrate in plants. • Glycogen is a storage carbohydrate in animals. • Liver and muscles

46. Lipids • Most diverse group of biomolecules • Solid at room temp = fat; • liquid at RT = oil • Contain much less O2 than CHOs • Often long chains of C • 4 categories: • Fatty Acids can be (un)saturated • Mono-, di-, and triglycerides • Phospholipids (polar) • Steroids • Eicosanoids (prostaglandins et al.) • Functions?

47. Triglycerides

48. Unsaturated (mono- & polyunsaturated) fats are liquid at room temp. Trans fats have added hydrogen (hydrogenated) (p 29) Triglycerides: 3 FA + Glycerol Saturated Unsaturated Polyunsaturated

49. Trans Fats

50. In cis bonds, the two pieces of the carbon chain on either side of the double bond are either both “up” or both “down,” such that both are on the same side of the molecule. • In trans bonds, the two pieces of the molecule are on opposite sides of the double bond, that is, one “up” and one “down” across from each other. • Naturally-occurring unsaturated vegetable oils have almost all cis bonds, but using oil for frying causes some of the cis bonds to convert to trans bonds.