CHAPTER 2: THE CHEMISTRY OF LIFE

OBJECTIVE OF CHAPTER: To understand how chemistry, certain elements, and compounds can have an effect on life.

MAJOR AREAS OF STUDY I.Structure of Atoms II.Elements and Compounds III.Chemical Bonds IV.Water and its properties V.Acids and Bases VI.Chemistry of Carbon VII.Chemical Reactions

CHAPTEROUTLINE CHAPTER OUTLINE I.Structure of Atoms A. Protons (a) Positive Charge (b) Located in Nucleus B. Neutrons (a) No Charge (b) Found in Nucleus C. Electrons (a) Negative Charge (b) Located outside the Nucleus

Atoms are neutrally charged, contain same number of protons and electrons Atomic number: number of protons in an atom Mass number: number of protons and neutrons (carry a mass of one) in an atom

II. Elements and Compounds A. Element: Consist of one type of atom 1. Isotope: Element with a different number of neutrons. Ex. Carbon 14 Isotopes have same number of electrons and chemical properties 2. Radioactive Isotopes: Elements with unstable nuclei Used to determine age, medicine, and kill bacteria

B. Compounds: Chemical combination of 2 or more elements ex. NaCl salt Compounds held together by Chemical Bonds. Chemical bonding involves the electrons (valence electrons) 1. Ionic a. Electrons are transferred b. One element becomes positive and the other negative 2. Covalent a. Electrons are shared b. Compounds in living things

3. Van der Waals Forces Attraction between positive and negative forces in covalent compounds Chemical Bonds 2 Rules: 1.When chemical bonds are joined energy is stored 2.When chemical bonds are broken energy is released.

IV. Properties of Water A. Liquid at normal temperature B. Expands when frozen C. Solid phase is less dense than liquid D. Slight positive and negative ends Polar molecule E. Creates Hydrogen bonds Cohesion: attraction between molecules of the same substance Adhesion: attraction between molecules of different substances (Capillary Action)

F. Solutions and Suspensions 1. Mixture: two or more elements or compounds that physically mixed together but not chemically combined. Can be separated by physical means. a. Solutions: Distributed evenly throughout Solute: what is being dissolved Solvent: substance in which solute dissolves in

b. Suspensions: materials which do not dissolve but maybe in small pieces and may float in the solvent V. Acids and Bases A. Acids 1. pH 7 or below 2. greater number of H + ions than OH - ions 3. sour tastehttp://youtu.be/QqjcCvzWwww

B. Bases 1. pH 7 or above 2. greater number of OH - ions 3. slippery 4. bitter taste Buffer: weak acids or bases that prevent sharp sudden changes in pH. Used by your body to maintain pH level in blood

VI. Carbon Chemistry Carbon: Has 4 valence electrons 4 possible bonding sites Can bond to P, S, N, O, H Can bond to other carbon atoms Polymerization: large compounds are built by joining smaller ones together. Monomers →Polymers

Four Groups of Organic Compounds A. Carbohydrates 1. Made up of carbon, hydrogen, and oxygen 2. Used for energy (glucose) 3. Glucose simple sugar C 6 H 12 O 6 called Monosaccharide (glucose, galactose, fructose) 4. Compound sugars are called Polysaccharide (glycogen, stored in liver, cellulose-plants)

B. Lipids: fats, oils, waxes 1. Not soluble in water 2. Mostly carbon and hydrogen 3. Can be used to store energy 4. Part of biological membranes and waterproof coverings 5. Steroids are lipids 6. Lipids are composed of Fatty Acids and Glycerol 7. 2 Types: Saturated: all carbon atoms occupied Unsaturated: one carbon double bonded

C. Nucleic Acids 1. Contain hydrogen, oxygen, nitrogen, carbon, phosphorus 2. Assembled from nucleotides 3. Nucleotides: consist of 3 parts: a 5-carbon sugar, phosphate group, and a nitrogenous base. Joined by a covalent bond 4. Nucleotides: Store and transmit hereditary or genetic information 2 Types: DNA: deoxyribonucleic acid (deoxyribose) RNA: ribonucleic acid (ribose)

DNA contains: Adenine, Guanine, Cytosine, Thymine RNA contains: Adenine, Guanine, Cytosine, Uracil D. Proteins 1. Contain nitrogen, carbon, hydrogen, oxygen 2. Made of units known as amino acids 3. Contains amino group NH - 2 and carboxyl group COOH -

4. Proteins control rate of reactions, regulate cell processes, form bones and muscles, transport, fight disease VII. Chemical Reactions Process that changes or transforms one set of chemicals into another Made up of Reactants and Products Exothermic Reactions: release energy or heat Endothermic Reactions: absorb energy or heat

1. Activation Energy: energy needed to start a reaction 2. Enzymes a. Catalyst: substances that speed up the rate of chemical reactions. Lowers the activation energy b. Enzymes affected by pH and temperature c. Enzymes provide a site where reactions can occur. Reactants are called substrates.