Some Essential Chemistry …for all the Biologists who aren’t Chemists 

Oxidation & Reduction Reactions (Re-dox) Involves the movement of ELECTRONS (doesn’t always occur in reactions with oxygen) LEO the lion says GER LEO = Lose Electrons Oxidized GER = Gain Electrons Reduced

Example NaCl  Na+ + Cl- Which element has been oxidized? How? Which element has been reduced? How? a. Na was oxidized as chlorine received an electron from sodium in the ionic bond of NaCl b. Cl was reduced as it received an electron from Na

Re-dox reactions involving covalent compounds Oxidation is the loss of HYDROGEN atoms and reduction is the gain of H atoms 1 hydrogen atom contains 1 proton & 1 electron, so… If a molecule loses an H atom, it has lost an electron If a molecule gains an H atom, it has gained an electron These types of re-dox reactions occur a lot in cellular reactions!

Dissociation of Acids & Bases When we break a molecule apart, we have dissociated it (ex. NaCl  Na+ + Cl-) When acids dissociate, hydrogen (H+) ions are released When bases dissociate, hydroxide (OH-) ions are released

An Acid… Will form H+ ions in solution Tastes sour Has a pH less than 7 Ex. HCl, lemon juice, vinegar

A Base… Will form OH- ions in solution Tastes bitter Has a pH of more than 7 Ex. NaOH, ammonia, household cleaners

pH Explain what is meant by the term pH. How can pH be raised or lowered? pH measures the level of acidity or basicity (alkalinity) of a solution. Increasing OH- ions will raise pH (more basic) whereas increasing H+ ions will lower pH (more acidic).

Buffers What is the purpose of a buffer? Buffers are chemical combinations that take up excess H+ or OH- ions in order to keep the pH of a solution CONSTANT. This is important for maintaining pH & homeostasis in living things!!!