Introduction to Biochemistry “Chemistry of Life”

Basic Chemistry Terms Atom = basic unit of matter Element = substance consisting entirely of one type of atom. Helium Atom

Basic Chemistry Terms Molecule = smallest unit of most compounds Compound = Chemical combination of more than one element, in a definite ratio.

Compounds

Chemical Bonding Bonds Strength Covalent bond > Ionic bond > Hydrogen bond Organic molecule= a carbon containing molecule (C-C or C-H) Ion = an atom that has gained or lost an electron, thus acquiring a charge

Covalent bonds = Strongest chemical bond in which two atoms share valence electron(s) Octet rule Ex. Water H2O Ex. Glucose C6H12O6

Ionic bonds Strong bond that results from the attraction between charged atoms. Electrons are given up. Bond dissolves in water creating ions Ex. NaCl (salts) Ex. CaCl2

Hydrogen bonds Weak bonds between hydrogen and other atoms. Result from polarity, electronegatvity. Very important in protein’s 3 dimensional structure. Ex. Water H2O Ex: Protein structure

Hydrogen bonds hold water together

Radioactive Isotopes Uses: Treat cancer Determine age of fossils Isotopes have different number of neutrons Nucleus of atom breaks down over time Carbon 12 Normal (6 neutrons + 6 protons) Carbon 14 Radioactive (8 neutrons + 6 protons) Uses: Treat cancer Determine age of fossils “tracers” in medical imaging

Chemical Reactions Occur when chemical bonds are broken, rearranged or formed. The sum of all chemical reactions in the body is known as metabolism. All systems tend to go toward entropy  disorder

Synthesis Reactions A + B AB Energy is required to form bonds Amino Acids Protein energy A + B AB Energy is required to form bonds Reactions are energy absorbing Anabolic (Constructive) reactions Monomers join to form polymers

Decomposition Reactions Glycogen Glucose molecules AB A + B + energy Energy is released to break bonds Reactions release energy Catabolic (destructive reactions) Complex nutrients are broken down

Electrolytes and Salts Made of cations/anions Disassociate in water Calcium phosphates makes bones and teeth hard Na+ & K+ help transmit nerve impulses and muscle contractions Kidneys maintain water level to keep ions concentrations in balance

Acids and Bases Each jump up in the pH scale is a ten fold increase taste sour pH <7 HCL  H+ + CL- Release H+ ions Proton donors H2SO4, HC2H3O2 Bases Taste bitter pH >7 Proton acceptor NaOH  Na+ + OH- HCO3-, NH3 Each jump up in the pH scale is a ten fold increase pH 5  7 = 100x H+ ions H2O is a weak acid

Buffers Acidosis- pH < 7.35 Alkalosis- pH > 7.45 Buffers Resist sharp swings in pH Blood must stay within 7.35-7.45 Biological molecules function at optimum pHs Acids and bases neutralize each other Acidosis- pH < 7.35 Alkalosis- pH > 7.45

Properties of Water

Water’s structure matches function Water is a polar molecule because the electrons from H are unequally shared. + + - -

Traits of water? Cohesion Surface Tension Adhesion Imbibition Universal Solvent The fact that water is polar allows for these traits

Universal Solvent Many substances will dissolve in water. Especially those found in organisms (blood).

Additional traits of water High Specific Heat High Heat of Vaporization Provides cushioning for body organs Solution for Biochemical reactions

High Specific Heat Water can absorb a lot of energy before its temperature changes. The large amount of water in living things prevent sudden changes in temp. in response to external or internal factors. In blood water keeps temperature homeostasis in tissues.

High Heat of Vaporization Water absorbs a lot of energy (540 cal/g) to change states…thus sweat cools us. When we lose 1 gram of water in sweat we lose 540 calories of heat

Cushions Organs Protects organs from physical trauma Cerebrospinal fluid protects the brain

Medium for Biochemical Rxns Biochemical reaction will only occur in solution. Dehydration Synthesis Removing water to form new molecules Hydrolysis Adding water to break bonds.