I NTRODUCTION TO B IOLOGY – P ART 2 T HE M OLECULES OF L IFE ( PP ) I. Importance of CarbonTest: 9/13 Although a cell is composed of % water, most of the rest is carbon – based compounds. A. Structure of carbon 1. Atom # 6: 6 protons & 6 electrons: 2 in the first shell & 4 in the second. 2. Has 4 valence electrons – so it can make four covalent bonds 3. Usually bonds with: hydrogen, oxygen, phosphorus, sulfur, and nitrogen 4. Can also bond w/other carbon atoms 5. Compounds with carbon-carbon bonds called organic

B. Macromolecules – macro = large, so these are very large molecules 1. Polymers a. Poly = many b. These are large molecules made up of similar or identical building blocks 2. Monomers a. Mono = one b. Are the building blocks or subunit of polymers

3. Classes of macromolecules are also called Biomolecules a. Carbohydrates b. Lipids c. Nucleic acids d. Proteins

II. Carbohydrates A. Elements: C, H, O, always a 1:2:1 ratio of H atoms to O atoms (2H:1O) B. Monomer: monosaccharide C. Function: immediate and stored energy; building material D. Where found in body: bloodstream, liver; cell walls of plants E. Food source: sugar and starches

F. Examples: 1. Monosaccharides: (simple sugar) a. Glucose (C 6 H 12 O 6 ) – preferred energy molecule for most organisms; including humans b. Galactose – one component of milk c. Fructose – found in some fruits 2. Disaccharides: 2 monosaccharides bonded together a. Sucrose – table sugar: glucose + fructose b. Lactose – milk sugar: glucose + galactose

3. Polysaccharides: more than 2 monosaccharides bonded together; two groups a. Storage Polysaccharides: long polymers of glucose; broken down for needed energy  Glycogen Storage of glucose in animals Stored in livers and muscles  Starch Storage of glucose in plants Humans can break down glucose for energy

b. Structural Polysaccharides: used for building materials  Cellulose Component of plant cell walls Humans unable to break down Important source of fiber in our food  Chitin Component of fungi cell walls Component of insect and other arthropod exoskeleton

III. Lipids: (waxy, fatty or oily) compounds A. Elements: C, H, O, many more H than in carbs. B. Monomer: glycerol & fatty acids C. Function: energy storage; insulation; cushioning D. Where found in body: cell membrane, innermost layer of skin, surrounding some organs E. Food Source: olive oil, corn oil, sesame oil, peanut oil, canola oil F. Example: 1. Fats and Oils a. All have 3 fatty acids b. Fats are solid at room temperature c. Oils are liquid at room temperature d. Saturated fats – no carbon – carbon double bond e. Unsaturated fats – at least one carbon – carbon double bond f. Saturated fats linked to heart disease

2. Phospholipids a. Unique lipid b. Found in every living cell membrane 3. Steroids a. Used for hormone production b. Used for animal cell structure c. Example: cholesterol, testosterone

IV. Proteins A. Elements: C, H, O, P, N B. Monomer: amino acids, only 20 different amino acids combine in different numbers, patterns & arrangement C. Function: support, structure, protection, movement, metabolism D. Where found in body: muscle, hair, skin, enzyme E. Food Source: meat, beans, eggs, dairy products F. Examples: 1. Enzymes a. Biological catalyst b. Trigger chemical reactions c. Could not maintain homeostasis without them

V. Nucleic Acids A. Elements: C, H, O, P B. Monomer: nucleotides C. Function: genetic instructions & usable energy D. Where found in body: nucleus of cells E. Food Source: none F. Examples: 1. DNA a. Deoxyribonucleic acid b. Contains the genetic instructions for the cell 2. RNA a. Ribonucleic acid b. Carries out the instructions in DNA 3. ATP a. Adenosine triphosphate b. Produces useable energy for the cell