Intro to Biochemistry What do you think is the cause behind these bird gatherings?? Salt licks/clay licks provide these birds with the minerals and ions they need but can’t get from their food sources.

The Atom Atoms are the smallest unit of matter and all elements consist of atoms. Atoms are composed of protons, neutrons and electrons. Interactions between electrons determines the type of bond that holds atoms together. Metallic Covalent Ionic Hydrogen

Atoms and Isotopes The number of protons (atomic number) is characteristic of each element. Sometimes the number of neutrons can vary which creates different isotopes. They have the same chemical properties but different masses. Most Isotopes are unstable and decay spontaneously giving off radioactive particles. Many isotopes are used in medicine as diagnostic tools.

Ions Ions are charged atoms Cations vs. Anions

Polarity Polar molecules are the result of differing electronegativity values between two different non- metals. There is an unequal sharing of electrons which leaves the molecule with a negatively charged portion and a positively charged portion. Some polar molecules include: Water (H20) Ammonia (NH3) Alcohols (OH) Hydrogen Fluoride (HF)

Chemical Reactions Chemical equation used to “paint a picture” of what is going on with the molecules/atoms in a reaction Reversible reactions occurring more frequently than we realize (equilibrium) Coupled reactions common theme in biochemical world

Biochemistry applications

Properties of H2O Water is polar with hydrogen bonding forming between the hydrogen of one water molecule and the oxygen of another water molecule. The unique characteristics of water is due to its polarity and hydrogen bonding. Organisms depend on water’s cohesive and adhesive properties: Cohesion Adhesion High Surface Tension

Properties of H2O Water moderates earth’s temperatures as well as helps moderate body temps: High specific heat High Heat of vaporization Density of phases (solid vs liquid)

Properties of H2O

Properties of H2O Water is the solvent of life. It can dissolve many compounds because of its polarity. Like dissolves like (only polar compounds will dissolve in water)

Properties of H2O and Acid/Base Chemistry: Water dissociates spontaneously to form H+ ions (hydrogen/proton) and OH- ions (hydroxide ion) In pure water, the [H+] = [OH]- = 10-7 M When acids or bases dissolve in water the [H+] or [OH-] changes. Acids increase the [H+], while bases reduces [H+]. pH scale = measurement of [H+] pH= - log [H+] Buffers…