1. Energy of Life

2. Why do Cells Need Energy? To maintain homeostasis For growth and development For the movement of materials For the building/breaking down of molecules To respond to their environment

3. Cells use Chemical Energy Energy is stored in the bonds between atoms. Energy is released when those chemical bonds break.

4. ATP and ADP Cells cannot use sugars for energy, so they must convert them to a usable form - - - ATP. 1 glucose can break down and create 38 ATP molecules. This happens in the mitochondria.

5. ATP and ADP Energy is stored in the bonds of ATP – Adenine – Ribose (sugar) – 3 phosphate groups Energy is released when ATP loses a phosphate group to form ADP. Human cells use about 125 pounds of ATP every day so the molecules must be recycled again and again.

6. ATP and ADP Recap…….. – ATP is adenosine triphosphate It has stored energy like a charged battery – ADP is adenosine diphosphate It has less energy like a partially charged battery

7. Limits of ATP – ATP is not good for storing energy for a long time. – Glycogen, starch, glucose, fat, are better for long term storage.

8. How Do Organisms Get Energy ? Autotrophs create their own food Photosynthetic convert light to chemical energy Chemosynthetic use inorganic chemicals for energy Ex: Plants, algae, archaebacteria

9. How Do Organisms Get Energy ? Heterotrophs must consume their food Ex: Humans, other animals