Bio-chemistry Notes Chp 2.1, 2.2

Organization of matter  Matter is anything that has mass and volume Weight is not a factor. Why? Can be in various states: liquids, solids, gases  Matter is made up of one or more elements. There are over ninety elements occur naturally Over 110 elements have been identified

Atoms  The building blocks of elements  All atoms have the same structure as the others but differ in the amounts of the materials  The nucleus of an atom Positively charged particles that are called protons (p + ) Particles with no charge called neutrons (n 0 )

Atoms  The energy levels that surround the atom contain a third particle Electrons (e - ) have a negative charge and balance the protons. Energy levels can only hold so many electrons  1st shell holds 2 electrons  2nd and 3rd shells can hold 8 electrons each

Atom Models

Elements  Everything is made from elements  Cannot be broken down any further except to be called atoms  25 elements are essential for living organisms  Trace elements are those elements that compose less than 0.01% of all the atoms inside that organism

Periodic Table

Interactions of matter  Chemical bonding relates to the interaction of atoms with other atoms  Two atoms of different elements join together to be called compounds

Three Types of Bonding  Covalent – sharing of electrons  Ionic – transfer of electrons  Hydrogen – inner-molecular force between molecules

Covalent Bond

Ionic Bond

Hydrogen Bond

Chemical reactions  Matter is neither created nor destroyed in a chemical reaction  Some examples of reading chemical reactions:  CH O > CO H 2 O Molecules? Atoms? Balanced?  Chemical reactions occur when the condition are right (temperature, energy)

Chemical Reactions

Isotopes  Although the numbers of electrons and protons are equal in a balanced atom, however, they might contain a different number of neutrons.  As the number of neutrons becomes unbalanced compared to the number of protons the nucleus itself becomes unstable. As the nucleus breaks apart it gives off radiation. Radiation is used in medical procedures today

Mixtures and Solutions  Mixtures are when you combine two things together and no reaction will occur. ex: Sand and sugar mixed together will not react  A solution is when two substances are mixed and do react with each other. ex: Kool-Aid and water, the substances react together  Solute is the dissolved material  The solvent is the dissolving substance  The more solute the high the concentration

Acids and bases  Use of the pH scale is to detect the amount of acid or base that a substances has.  The scale has numbers from 1 to 14. Above 7 is a base Below 7 is an acid 7 is neutral.  Acids have hydrogen ions (H+)Bases have hydroxide ions (OH-)