Chapter 2: The Chemistry of Life Section 2.2: The Compounds of Life

Objective:  A Explain the structural and functional similarities and differences found among living things.  B Describe and explain the chemical and structural basis of living organisms

Carbon  Can form 4 covalent bonds.  Bonds – short and strong; can form long, stable chains.  Can form bonds with other carbon (C) atoms, hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P) and other elements.

 NO element matches carbon in forming chains of different shapes, sizes and complexity.

Organic compounds contain at least 2 C atoms (with some exceptions).  All other compounds are inorganic compounds.

Sub-Objective:  Define macromolecule.  Identify the 4 major classes of macromolecules.

Macromolecules:  Monomers, meaning single units, are small molecules.  Polymers, meaning many units, are assembled by combining monomers to form large molecules.  Macromolecules, meaning giant molecules, are very large polymers.

4 Major Macromolecules  Carbohydrates

Carbohydrates  Include sugar and starches  Composed of C, H, and O.  Generally contain 2 H atoms for every O atom.  Short term storage of energy and structural components of some cells.

Three Types of Carbohydrates  Monosaccharides –simple sugars (one unit).

Monosaccharides  Lactose - found in milk.  Fructose – found in fruit.  Glucose – found in the cells of every organism.  They are isomers - All have the same formula C 6 H 12 O 6, but each has a slightly different arrangement of its atoms.

Three Types of Carbohydrates  Monosaccharides –simple sugars (one unit).  Disaccharides – 2 simple sugars bonded together.

Disaccharides  Sucrose – table sugar  Lactose – milk sugar  Maltose – malt sugar  The above are isomers of each other. C 12 H 22 O 11

Three Types of Carbohydrates  Monosaccharides –simple sugars (one unit).  Disaccharides – 2 simple sugars* bonded together.  Polysaccharides - many monosaccharides bonded together.

Polysaccharide  Starch – storage form of energy for plants.  Glycogen – storage form of energy for animals.  Cellulose – structural component of plant cells.  Chitin – structural component of exoskeletons and fungi.

Lipids  Made from C, O and H.  Waxy, fatty or oily compounds.  Long-term storage of energy.  Oils and fats: * Composed of fatty acid chains and a glycerol backbone. * Act as insulators and cushions.

Lipids  Waxes: * Different backbone than oils and fats. * Act as waterproofing materials for plants and animals.

Lipids  Phospholipids * Composed of fatty acid chains, a glycerol backbone and a phosphate group. * Forms the structural basis of cell membranes.

Lipids  Sterols * Series of carbon rings. * Important role in building cells and carrying messages in the body. * Cholesterol and steroid hormones.

Proteins  Polymers of amino acids (20 common amino acids).  Amino acids are composed of: * Central carbon atom * Hydrogen atom * Amino group (-NH 2 ) * Carboxyl group (-COOH) * An R group

Protein  The R group is what makes each amino acid different.  Amino acids join between the amino and carboxyl groups to form a peptide bond.  Chain of amino acids = polypeptide.

Proteins  Principal components of feathers, skin and muscles.  Help chemical reactions to proceed (enzymes).  Pump small molecules in and out of cells.

Nucleic Acids  Information carrying molecules.  DNA and RNA  Assembled from nucleotides.

Nucleic Acids  Nucleotides consist of: * Phosphate group * Nitrogen base * 5-C sugar either deoxyribose (DNA) or ribose (RNA). * 4 different nucleotides in both DNA and RNA. * Arrangement of the nucleotides determines the information that the nucleic acid contains.

ATP  Temporary energy storage in cells.  Composed of nucleotides