Life Science Chapter 3 Lesson 3 Cell Energy • Energy- The ability to do work • God maintains life with energy to the sun • Plants use photosynthesis to turn sun energy into food Cellular Respiration • Defined: the breaking down of food molecules by cells into usable energy • Most cellular respiration is done in the mitochondria ATP • (adenosine triphosphate) the molecule that carries small packets of energy for the cell’s activity • Most energy is released in the form of heat, helping maintain body temperature Metabolic Pathway • A series of chemical reactions that breaks down or makes materials we all need • They usually contain about a dozen different steps • Red blood cells have pathways that manufacture hemoglobin molecules Enzymes • Special proteins that speed up chemical reactions in an organism or cell • Without enzymes, reactions inside the cell would be to slow to maintain life Pop Quiz • Get a sheet of paper • Answer the following questions: • 1. Do cells create energy? • 2. What is the metabolism of a cell? • 3. Why do you think there are so many different types of enzymes?