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Chapter 2: Chemicals of Life

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A. Bonding 1. Covalent Bonds 2 or more atoms share electrons to form a molecule No net charge due to equal number of + and Ex. water

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Properties of Water Covalent bonding vs. Hydrogen bonding Covalent Bond Hydrogen Bond

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A. Bonding 2. Hydrogen Bonds Weak bond between polar molecules

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A. BondingBonding 3. Ionic Bonds Gained or lost one or more electrons Charged due to unequal number of electrons or protons Ex. NaCl

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B. Properties of Water a.Water heats slow b.Retains heat longer c.Helps maintain homeostasis 1. High Heat Capacity

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B. Properties of Water Water is the solvent of Life! Solute substance dissolved in a solvent to form a solution Solvent fluid that dissolves solutes Example: Ice Tea water is the solvent and tea and sugar the solutes 2. Universal Solvent

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B. Properties of Water a. cohesion = water attracted to other water molecules because of polar properties ex. Forms drops or film surface tension = water is pulled together creating the smallest surface area possible b. adhesion = water attracted to other materials ex. Getting wet, capillary action 3. Cohesion, Adhesion and Surface Tension

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B. Properties of Water 4. Capillary Action = Water molecules move due to adhesive and cohesive properties as a result of the original adhesion. Ex: Think water in a straw Ex: Water moves through trees this way

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B. Properties of Water 5. Water is a polar molecule. Many substances will dissolve Non-polar molecules will not dissolve

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C. Classes of Organic Molecules: What are the four classes of organic molecules? Carbohydrates Lipids Proteins Nucleic Acids

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1. Carbohydrates Sugars Carbo = carbon, hydrate = water; Oxygen Functions: Store energy in chemical bonds Glucose is the most common monosaccharide Monosaccharides Disaccharides Polyshaccharides

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1. Carbohydrates Benedicts Test

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1. Carbohydrates Iodine Starch test

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2. Lipids Structure: Greasy or oily nonpolar compounds Functions: Energy storage membrane structure Protecting against drying out. Insulating against cold. Absorbing shocks.

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2. Lipids Saturated and Unsaturated Fats Unsaturated fats : liquid at room temp one or more double bonds between carbons in the fatty acids allows for kinks in the tails most plant fats Saturated fats: have only single C-C bonds in fatty acid tails solid at room temp most animal fats

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2. Lipids. Phospholipids Structure: Glycerol + 2 fatty acids + phosphate group. Function: Main structural component of membranes, where they arrange in bilayers.

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3. Proteins Structure: Polypeptide chains Consist of peptide bonds between 20 possible amino acids Have a 3 dimensional globular shape

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3. Functions of Proteins Enzymes speed up a chemical reaction Structural materials keratin (the protein found in hair and nails) collagen (the protein found in connective tissue) Specific carriers Carry materials across cell membrane, carry oxygen in blood

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3. Proteins: Structure of Amino Acid Hydrogen Amino group Carboxyl (acid) group Variable R group specific to each amino acid

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4. Nucleic Acids Two kinds: DNA: double stranded can self replicate makes up genes which code for proteins is passed from one generation to another RNA: single stranded functions in actual synthesis of proteins coded for by DNA is made from the DNA template molecule