Metabolic Processes

• Living things are complex and yet, the cell is the basic unit of life
• New cells result of mitosis cell division
• DNA controls all cell functions
• In living organisms there is a balance between anabolic and catabolic processes

             -Anabolic à taking smaller molecules and making them into larger ones
                              E.g. photosynthesis and protein synthesis

             -Catabolic à taking larger molecules and breaking them down into smaller ones

                               E.g. cellular respiration

              -Anabolism + catabolism = metabolism

• Metabolic processes need to be taking place for an organism to survive

                              E.g. of metabolic processes

                           Photosynthesis, cellular respiration, digestions, dehydration, protein synthesis and leaves changing colours in fall

• Living things have chemicals reacting together è chemistry drive all life

Chemistry to remember

• Sugar and acids dissolve well in water due to their polar bonds
• Carbon is a versatile atom since it can form 4 bonds that are usually very stable
• Humans lack the enzyme to break down the β - glucose found in cellulose in grass
• Blanching food denatures the enzyme that would react to air and cause an 'off taste'

• Matter - has mass and takes up space

Atoms are the smallest unit of matter

o   Electrons, protons and neutrons

o   Protons + neutrons = atomic mass

• Isotopes
  • Atoms with same # of protons but a different number of neutrons
• Radioisotopes
  • Isotopes that decay over time into smaller atoms, sub-atomic particles and energy
  • Have a half-life è time it takes for half the mass to decay away
  • Uses à radiometric dating, radioactive tracers, nuclear medicine
  • Radiation à cause mutations, cellular damage and possible death
• Intramolecular Bonds è bonds within a molecule
  • Ionic (metal-nonmetal)
  • Covalent
• Electronegativity
  • Measure of an atoms ability to attract a shared electron pair when participating in a covalent bond
  • Atom that has higher E_n à attract pair better à slightly negative δ^-
  • E_n differences

  0 - 1.7 à non polar/polar à 1.7 - 4.2 à ionic

• Polarity
  • Depends on E_n differences and symmetry
• Intermolecular Bonds è bonds between molecules
  • London Dispersion

                        Weak and based on size of atom/# of electons

                        Affects all molecules

               o   Dipole-Dipole

                     Occurs in polar molecules

               o   H-bonds

                    Strongest bond occurring between H and NOF

• Water has strong polar bonds
  • H-bonds are very important for they cause...

 Cohesion à water sticks together causing high surface tension

Adhesion à water sticks to other things causing capillary action

• High heat capacity
• High vapour pressure

o   Solid water is less dense then liquid

o   Very good solvent

o   Small non-polar molecules (e.g. O₂ & CO₂) need protein carrier molecules to dissolve

o   Nonpolar = hydrophobic; Polar = hydrophilic

o   Water ionizes very little into H₃O and OH

• Acids and Bases
  • Strong acids ionize completely where as weak ones only ionize a bit
  • The acid donates the proton (H⁺) and the base accepts the proton

  Conjugate acid-base pairs

  These also act as buffers for the pH in our body