How Organisms Obtain Energy

1. How Organisms Obtain Energy Section 8.1

2. I. Transformation of Energy • Energy is the ability to do work • Thermodynamics • Study of flow and transformation of energy in the universe

3. II. Law of Thermodynamics • First Law • Energy can be converted from one form to another; it cannot be created or destroyed. • Second Law • Energy cannot be converted without the loss of usable energy

4. III. Autotrophs and Heterotrophs • Autotrophs • Organisms that make their own food. • Heterotrophs • Organisms that need to ingest food to obtain energy.

5. IV. Energy in Cells • Metabolism • All of the chemical reactions in a cell • Photosynthesis • Light energy from sun is converted to chemical energy for use by the cell (anabolic pathway) • Cellular Respiration • Organic molecules are broken down to release energy for use by the cell (catabolic pathway)

6. V. ATP: The Unit of Cellular Energy • ATP (adenosine triphosphate) releases energy • Bond between second and third phosphate groups is broken • Forms adenosine diphosphate (ADP) and a free phosphate group

7. Which statement describes the law of conservation of energy? • Energy cannot be converted or destroyed. • Energy can be converted and destroyed. • Energy can be converted but not destroyed. • Energy can be destroyed but not converted. Answer: C

8. Which law of thermodynamics explains why the ladybug receives the least amount of usable energy? Answer: The second law of thermodynamics

9. True or False All of the energy from the food you eat comes from the sun. Answer: True

10. Why is adenosine triphosphate (ATP) such an important biological molecule? • It captures light energy from the sun. • It is produced in anabolic pathways. • It stores and releases chemical energy. • It converts mechanical energy to thermal energy Answer: C