Atomic Structure and Properties Chemistry of Life Atomic Structure and Properties Chemical Bonding Macromolecules Chemical reactions

Prior Knowledge Write everything you know about the following equation. C6H12O6 + 6O2 6CO2 + 6H2O

Atoms The basic unit of matter is an ATOM. Atoms are broken into 3 parts Protons (+ charge) found in the nucleus Neutrons (no charge) found in the nucleus Electrons ( - charge) found in constant motion around the nucleus (orbitals) A substance made up of only one type of atom is called an element (N2) A substance made up of more than one type of atom is called a compound. (ex H2O)

Electrons can be added or lost to create a charged atom called an ion. A typical atom can exist in two different forms which affect the atomic properties: Neutrons can be added (common) or lost (uncommon) to form isotopes. Uses? Electrons can be added or lost to create a charged atom called an ion. Losing electrons create a positive charge (cation) Gaining an electron forms a negative charge (anion) Interactions of atoms are mostly a product of moving electrons (bonding, electricity, conduction, etc)

                                                      

Chemical bonds 3 main types of bonds (two biological) Metallic Bonds form between two metals (very strong) example Fe3 Ionic Bonds form from sharing of electrons (weak) example NaCl Covalent Bonds form from the sharing of electrons. (Strong) example CH4

CO2 NH3CH2CO2

Identify MgF2 CaO N2O3 Li3N C6H12O6

Transfer of electrons Sharing of electrons Weak bonds Strong Bonds Ionic Bonds Covalent Bonds Transfer of electrons Sharing of electrons Weak bonds Strong Bonds Metal and non-metal Two non-metals Enegativity 1.8 or more Enegativity 1.2 or less Examples: Examples: NaCl, CaO, MgF2 CO2, F2, P4S10

Properties of H2O Water molecules are neutral (no net charge). Why then is water one of the best electrical conductors? Water is a polar molecule which forms both covalent and ionic bonds. Polar covalent bonds form between Hydrogen and Oxygen creating a (+) charge on the H and a (-) charge on the O. Hydrogen bonds from between water molecules. The positive H attracts the negative O. The result is a matrix with unlimited bonds.

Cohesion is the attraction between molecules of the same substance. Adhesion is the attraction between molecules of different substances. Mixtures are formed by two or more molecules which are phyiscally joined but not chemically. Solutions: all components are spread evenly Solute: dissolved substance (solid) ex. salt Solvent: substance doing the dissolving (liquid) ex H2O

Acids / Bases What happens when you split a water molecule? You get two charged molecules that are the basis of many chemical reactions Acids are formed from large concentrations of H+ ions (hydrogen ions). pH scale from 1 - 6 Bases are formed from large concentrations of OH- ions (hydroxide ions) pH scale from 8 – 14 Water consists of both ions and thus is neutral at pH of 7.

Organic Chemistry Organic chemistry is the study of compounds with bonds between carbon atoms. Carbon compounds are the base to all living organisms (organic). There are 4 groups of large organic compounds called macromolecules.

Carbohydrates Sugars / starches Mainly used for energy and structure in organisms Simplest of the four macromolecules Monosaccharides – simple sugars (glucose) Polysaccharides – complex chain of monosaccharides (starch)

Lipids Fats, oils Contain mostly carbon and hydrogen Source of stored energy for organisms Found in membranes and barriers (skin) Non-water soluble (does not allow water to pass)

Proteins Made up of long chains of amino acids (bonded through hydrolysis) Contain nitrogen, carbon, hydrogen, and oxygen. The most complex macromolecule. Proteins have a variety of functions: Structure and support (forms bone and muscle) Regulates cell process and controls chemical reaction rates Transports materials Fights diseases

Comparing Macromolecules What element is different between Proteins and sugars?

Sugar Structure

Lipid structure

Protein Structure

Nucleic Acids Contains nitrogen, oxygen, carbon, hydrogen, phosphorus Stores genetic information Transmits genetic information (codes for proteins)

Chemical Reactions Your body is a complex system going through thousands of chemical reactions every second. Energy, protein production, waste removal, oxygen transport, muscle contractions, are all examples of chemical reactions.

What is the difference between a chemical and physical reaction? C6H12O6 + 6O2 6CO2 + 6H2O Reactants Products Chemical reactions break chemical bonds in the reactants to form new (different) products Exothermic Reaction – releases energy Reactants are larger than products Endothermic Reaction – requires energy Products are larger than reactants

Types of Chemical Reactions Decomposition (Break down) Synthesis (Build-up) Single displacement (re-arranging) Double displacement (re-arranging) Combustion (burning) What are the products and reactants?

Does water and carbon dioxide naturally combine to make sugar? No, it requires a specific amount of energy applied to the two chemicals to start the chemical reaction. This is called Activation Energy. Organisms are able to control reactions by using substances called catalysts which can control the rate of a reaction. Some of the most important catalysts are found inside your body and cells, these biological catalysts are called Enzymes.

Enzymes (biological catalysts) work by attaching to a substance (substrate) at a specific recognition site called an active site. This is the same process used by antibodies and to fight off diseases. Why then can your body not fight off the disease called HIV or AIDS? (what type of cell fights diseases?)