Biochemistry

1. Biochemistry The Chemistry of Life

2. Basic Chemistry • Atom • Simplest unit of matter • Made up of three different “subatomic” particles

3. Subatomic Particles • Protons • Have a positive charge (+) • Have mass • Located in nucleus • Neutrons • Are neutral, have no charge (0) • Have mass • Located in nucleus • Electrons • Have a negative charge (-) • Almost no mass • Located in “energy levels” outside of nucleus

4. Atomic Number: • Tells you the number of protons an atom has, and also the # of electrons Atoms are neutral # Protons (+) = # Electrons (-)

5. Atomic Mass: • Add together the number of protons and neutrons in nucleus of atom • Electrons hardly contribute any mass

6. Isotopes: • Atoms of one type of element with different atomic masses • Same # of protons • Different # neutrons • Changes the mass only, the properties are the same

7. Radioactive Isotopes: • The nucleus of some isotopes is unstable • The atom with emit radiation • Radiation can be measured with tools • ex. Geiger counter • These isotopes can be used as useful tools in science • Ex: • Carbon-14 dating • Radiation treatment for cancer

8. Elements • Substance made of only one type of atom • Each element has a unique atomic # • Elements most commonly found in living things • Carbon (C) • Hydrogen (H) • Oxygen (O) • Nitrogen (N)

9. Compounds • Two or more elements chemically combined • Atoms held together by bonds. • Once bonds form, compounds will have new, and different properties

10. Organic Compounds • Contains carbon and hydrogen (and often O, N) • Ex: Glucose (C6H12O6), carbohydrate, lipids, proteins • Inorganic Compounds • Doesn’t contain carbon and hydrogen together • Ex: H2O, CO2, NH3, NaCl

11. Why do atoms form compounds? • Bonds that form between atoms give atoms a stable outer electron level. • Called a “stable octet” of valence electrons (8)

12. Types of Chemical Bonds • Ionic Bonds: • One or more electrons are transferred from one atom to another. • Neutral atoms become positive & negative ions • Forms salts • (Ex: NaCl) Ionic bond = attraction between (+) and (-) ions

14. Covalent Bonds: • Electrons are shared between atoms • Each bond represents a shared pair of electrons • Can form single, double or even triple bonds

15. Covalent bonds form molecules • Subscripts in the formula tell # of each atom • Ex: H2O, NH3, CO2, CH4

16. Ionic Bonds: Transfer electrons Covalent Bonds: Share Electrons

17. Properties of Water • Water is necessary for life • Contains covalent bonds

18. Water Molecules: H2O (look like Mickey Mouse)

19. Water is a “Polar” molecule (like a magnet) • The bonds are “polar” • Oxygen attracts the electrons more than Hydrogen

20. Hydrogen Bonding: bonding between the (+) H of one molecule and the (-) end of another molecule. • Makes water good at sticking to itself and other substances • Makes water good dissolver

21. Cohesion: water sticks to itself • Ex: • Water forms “beads” on smooth surface • Surface Tension allows insect to “skate”

22. Adhesion: water sticks to other substances • Ex: Capillary action: water molecules rise up small tubes

23. Heat Capacity: • Water has a relatively high heat capacity • Ex: • Lakes and oceans can absorb a lot of heat from sun without a drastic temperature change

24. Water as a Solvent: • Dissolves most ionic and covalent substances • “Universal Solvent” = many things can dissolve in it.

25. Solute: substance being dissolved • Solvent: substance in which solute dissolves • Solution: evenly disbursed mixture • Suspensions: material in the water but just suspended not dissolved (ex: blood cells in blood)

26. pH of Solutions • pH Scale: way to measure concentration of H+ ions in solution • Ranges from 0 to 14 • Pure water is neutral pH = 7

27. Litmus Paper: • Used to test pH of a solution • Red = acidic • Blue = basic

28. Acids: Form H+ ions • pH is <7 • Ex: HCl (stomach acid), lemon juice

29. Bases: Produces OH- (hydroxide ions) • Also called “alkaline” • pH >7 • Ex: Lye (NaOH) used as drain cleaner

30. Buffers: • Maintain pH at a certain level • Usually between 6.5 – 7.5 (close to neutral) • Helps to maintain homeostasis in organism

31. Major Types of Chemical Reactions • Dehydration Synthesis: (Condensation) • Chemically combine two smaller molecules • Water is removed • “Dehydrate” = remove water • “Synthesis” = to make

32. Hydrolysis: • Break apart large molecule into smaller pieces • Water is added • “Hydro” = water “Lysis” = to break

33. Polymerization: • Create a large molecule (polymer) • Join up smaller “monomer” units • Often a dehydration synthesis reaction Ex: Join amino acids (monomer) to make protein (polymer) Join glucose (monosaccharide) to make starch (polysaccharide)

34. Organic Compounds

35. Carbohydrates • Sugars and starches • FUNCTION: • Used as an energy source • Energy released during cellular respiration • Made of carbon, hydrogen and oxygen Ex: C6H12O6, C12H22O11 • Ratio of H of O is always 2:1

37. Basic Structure: • “Ring” made of 5 carbons and 1 oxygen • Rings can join up by dehydration synthesis

38. 3 Types of Carbohydrates • Monosaccharide's: 1 sugar ring • Disaccharides: 2 sugar rings • Polysaccharides: many sugar rings

39. Monosaccharide's: (Simple sugars) • All have formula C6H12O6 • Single ring structure • End in “-ose” • Ex: glucose, fructose, galactose

40. Disaccharides: double sugars • All have formula C12H22O11 • End in “-ose” • Ex: sucrose, lactose, maltose

41. Polysaccharides: 3 or more sugar units • Ex: • Starch (energy storage in plants) • Glycogen (how animals store sugar in liver) • Cellulose (plant cell walls) • Chitin (insect exoskeletons)

43. Simple sugars form into complex sugars by dehydration synthesis (condensation). • Combining molecules by removing water Monosac. + Monosac.  Disac. + Water C6H12O6 +C6H12O6  C12H22O11 + H2O

45. and H2O

47. Complex sugars are broken down into simple sugars by hydrolysis. • Breaking down molecules by adding water • Also called chemical digestion Disac.+ Water Monosac. + Monosac. C12H22O11 + H2O  C6H12O6 +C6H12O6

49. Dehydration Synthesis and Hydrolysis are OPPOSITE Reactions

50. **Chemical reactions are often enzyme mediated.