Chapter 2-Chemistry of Life Chemistry is the branch of science that looks at what things are made of and the changes that take place within these substances

Matter: anything that has mass and occupies space. Elements: basic chemical substances…(periodic table) Atoms: the smallest complete particle of an element.

Atomic Structure Nucleus: center of the atom; contains the protons/neutrons Protons: have positive charge Neutrons: no charge Electrons: outside the nucleus and have negative charge

Stuff I learned in Chemistry… Atomic number: the number of protons in the nucleus…the identifying number of an element(SS#) Atomic weight/mass: the number of protons + neutrons(the mass of nucleus)

Atoms may gain, lose, or share electrons… Atomic Bonding Atoms may gain, lose, or share electrons… When atoms gain or lose electrons, they become ions. Lose electrons = + ion Gain electrons = - ion

Ionic Bonding Ionic bonds occur when ions with opposite charges are attracted to one another Ex: Na(+) and Cl(-) become NaCl-common salt

When atoms share electrons, they are bonding covalently. Covalent bonding When atoms share electrons, they are bonding covalently. Molecule: when 2 or more atoms bond. Ex. O2 or H20 Compound: when atoms of different elements join.Ex. H20

1-Synthesis: A+B—› AB H2+O=H2O 2-Decomposition: AB—›A+B H2O—›H2+O Chemical Reactions 1-Synthesis: A+B—› AB H2+O=H2O 2-Decomposition: AB—›A+B H2O—›H2+O 3-Exchange: AB+CD—›AD+CB 4-Reversible: A+B‹—›AB (requires a catalyst)

Acids and Bases Some compounds release ions when they react with water. These are called electrolytes. Acids: release Hydrogen ions(H+) HCl—H+ + Cl- Bases: release Hydroxyl ions(OH-) NaOH—Na+ + OH-

pH Scale Goes from 0-14 7 is neutral Less than 7 is acidic Greater than 7 is basic pH of blood is 7.4 (7.35-7.45) Stomach acid is around 2.0 Tums/MOM is around 10.0

In general….organic means to contain Carbon/Hydrogen Organic vs. Inorganic In general….organic means to contain Carbon/Hydrogen Organic compounds: carbohydrates, lipids, proteins, and nucleic acids Inorganic compounds: water, oxygen, carbon dioxide, salts

Oxygen: used by our cells to drive chemical reactions(Kreb’s cycle) Inorganic compounds Water: most abundant compound in living material. Most important solvent in body. Oxygen: used by our cells to drive chemical reactions(Kreb’s cycle)

Carbon Dioxide(CO2): waste product from chemical reactions Inorganic Salts: sources of ions;needed for contraction of muscles, conduction of nervous impulses. Ex. Na, Cl, K, Ca, Mg

Organic Compounds Carbohydrates: provide energy for cells. monosaccharides: simple sugars Ex. Glucose and fructose disaccharides: double sugars Ex. Sucrose and lactose -polysaccharides: many sugars Ex. Plant starch, glycogen

Lipids: insoluble in water Ex. Fats, phospholipids,&steroids All used to build cell parts, supply energy, and make hormones

Nucleic Acids: carry genetic info. Proteins: made of amino acids -> used for structural materials and energy; Ex. Hormones, enzymes, and Hemoglobin Nucleic Acids: carry genetic info. Ex. DNA and RNA