1. CYCLING & RECYCLING OF MATTER 2.1

2. FYI  Life has 5 major requirements  Energy, Water, Inorganic Carbon, Oxygen, & Nutrients  Oxygen and nutrients are generally combined with carbon and oxygen. We call these mixtures “organic compounds”.

3. The Importance of Cycling  Because our biosphere contains a limited (or finite) number of atoms, new compounds can only be formed from atoms that are released during cycling.  It is essential that matter be recycled to help balance our biosphere and maintain life on earth.  The cycling of organic compounds happens in 2 ways Eating and digestion Decay and decomposition

4. Important elements and compounds  C – carbon is a component of organic molecules of which all organisms are composed  CO 2 – carbon dioxide is necessary for photosynthesis which is needed to begin the food chains and food webs  O 2 – oxygen (gas) is necessary for most living things

5.  H 2 O – water is necessary for all organisms  C 6 H 12 O 6 – sugar (glucose) is a form of food storage in plants and a source of energy of organisms  N – nitrogen is a component of proteins and nucleic acids (DNA; Chromosomes)  N 2 gaseous nitrogen is the most abundant gas found in the air Important elements and compounds

6. Homework NOW!  Page 51: 1, 2, 4, 5

7.  NO 3 – nitrate is a useable form of nitrogen; often formed by bacteria in the soil and on roots  P – phosphorous is found in energy storage called ATP; also found in nucleic acids  PO 4 phosphate is a common form of phosphorous found in rocks, soil, limestone etc…