1. Biochemistry A living things are composed of compound which contain these four elements: Carbon Hydrogen Oxygen Nitrogen

2. Carbohydrates The carbohydrates in living things are the fuel for cellular activities. Simple carbohydrates are also called monosaccharides. Monosaccharides are joined together by a process called Dehydration Synthesis (condensation reaction)

3. Complex Carbohydrates Two monosaccharides joined together are called a disaccharide. Many monosaccharides joined together form a polysaccharide Starch Glycogen Cellulose

4. Lipids Include fats, oils and waxes Used for stored energy and to make membranes (phospholipids) Are non polar so they do not mix with water Are made from fatty acids and glycerol Can be saturated (all carbon atoms single bonded) or unsaturated (at least one carbon to carbon double bond)

5. Nucleic Acids Store and transmit genetic information. Come in two forms DNA and RNA RNA has ribose sugar, is single stranded and comes in three forms mRNA, tRNA and rRNA. It is made from the nucleotides Adenine, Cytosine, Guanine and Uracil DNA has deoxyribose sugar and is a double strand (double helix) It is made from the nucleotides Adenine, Cytosine, Guanine and Thymine

6. Proteins Are composed of Amino Acids (20) They make up the structural parts of cells, enzymes, antibodies, hormones and membrane proteins. Chemically they consist of an amine group (NH 2 ) and a carboxyl group (COOH) and an “R” group. There are 20 different R groups

7. Chemical Reactions All chemical reactions in living things are catalyzed by enzymes. Enzymes are special proteins that help lower the activation energy of a chemical reaction » Enzymes combine with the substrate at the enzyme’s active site and help the chemical action proceed. » Enzymes may bring molecules together or help break them apart » Enzymes are very specific » Enzymes are able to be used over and over again