Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Section 1 Cell Energy Chapter 5 Bellringer Why might cells need energy? List ways that cells might get energy. Write your answers in your science journal.

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 What You Will Learn In plant cells, chloroplasts capture energy from the sun in order to make food during photosynthesis. Cells release energy from food through either cellular respiration or fermentation. Section 1 Cell Energy

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 From Sun to Cell All cells need energy to carry out cell functions. However, cells may obtain and process energy in different ways. Nearly all of the energy that fuels life comes from the sun. Plants absorb energy from the sun and change the energy into food through a process called photosynthesis. Section 1 Cell Energy

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 During photosynthesis, plants use the sun’s energy to change carbon dioxide and water into food. The food, in the form of the sugar glucose, is used by the plant and stored as starch. The stored food can then be eaten by other organisms. Photosynthesis also produces oxygen as a waste product. Section 1 Cell Energy From Sun to Cell, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 From Sun to Cell, continued Section 1 Cell Energy

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu The Cell in Action Photosynthesis Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 Getting Energy From Food Animals and other organisms that are not producers must eat to get food. Once food is eaten, it must be digested and broken down within the cells. Even plants must break down their food within their cells. The process by which organisms break down their food using oxygen is called cellular respiration. Section 1 Cell Energy

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 The word respiration means breathing, but cellular respiration is a chemical process. During cellular respiration, food is broken down into CO 2 and H 2 O, and energy is liberated. The energy is used to make ATP, a molecule used to power cellular activities. Section 1 Cell Energy Getting Energy From Food, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 In eukaryotes, cellular respiration takes place mostly in the mitochondria. In prokaryotes, it takes place in the cell membrane. Section 1 Cell Energy Getting Energy From Food, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Section 1 Cell Energy Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 Getting Energy From Food, continued The process of photosynthesis creates the materials needed for cellular respiration, and vice versa. When oxygen is not available, cells may obtain energy from food in a process called fermentation. Cellular respiration releases more energy from food than fermentation does. Section 1 Cell Energy

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 Section 1 Cell Energy

Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter menu Chapter 5 Section 1 Cell Energy