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2 Ch 9: Energy in a Cell ATP, Photosynthesis and Cellular Respiration ATP, Photosynthesis and Cellular Respiration

3 I. Energy A. A. Energy is essential for life. All living organisms must be able to obtain energy from the environment they live in. B. B. Plants are able to trap the light energy in sunlight and store it to use when necessary. (Autotrophs)

4 C. C. Animals obtain energy from plants or other animals that eat plants. (Heterotrophs) D. D. Energy is stored in chemical bonds of ATP = adenosine triphosphate.

5 ATP made of: made of: 1. adenosine molecule 2. ribose sugar 3. three phosphates held together by chemical bonds held together by chemical bonds

6 ATP Cycle When a phosphate is broken off of ATP, energy is released and ADP is formed. When a phosphate is broken off of ATP, energy is released and ADP is formed. When a phosphate is added to ADP, energy is stored and ATP is formed. When a phosphate is added to ADP, energy is stored and ATP is formed. **So the way energy is stored and released with ATP is to add or remove a phosphate.

7 Formation and breakdown of ATP creates a source of energy adenosine PP P P P P P Adenosine triphosphate ( ATP ) Adenosine diphosphate ( ADP ) energy

8 III. ATP Equation This formula is a true reversible reaction and is shown with a double- headed arrow. The molecules can be used over and over again. It can be written with ATP on the left or on the right. ADP + P + energy ATP ADP + P + energy ATPOR ATP ADP + P + energy ATP ADP + P + energy

9 Uses of Cell Energy A. A. Provide energy for muscle cells (muscle contraction) B. B. Cell division and cell repair C. C. Maintain homeostasis D. D. Transport molecules and proteins through the cell membrane. E. E. Making molecules

10 Photosynthesis

11 Vocabulary A. Photosynthesis – process by which autotrophs turn sunlight into chemical energy; make food B. Pigments – compounds that absorb/reflect wavelengths of light

12 Vocabulary C. Chlorophyll – green pigment found in plant chloroplasts D. Chloroplast – cell organelle where photosynthesis occurs

13 What is the ultimate source of all energy?

14 How does the energy get from the sun into the foods we eat? energy

15 What process captures the light energy and uses it to make food?

16 OVERVIEW OF PHOTOSYNTHESIS PLANTS TAKE IN CO 2 AND H 2 O PLANTS MAKE GLUCOSE AND OXYGEN SUNLIGHT PROVIDES THE ENERGY FOR PHOTOSYNTHESIS

17 Photosynthesis What is photosynthesis? What is photosynthesis? Photosynthesis is the process by which: Photosynthesis is the process by which: water carbon dioxide oxygen glucose TAKE INAND USINGMAKE PLANTS (producers) light chlorophyll

18 Photosynthesis Formula How would this be written as a chemical equation? What goes in? (the reactants) What comes out? (the products) H2OH2O Light Reaction Dark Reaction CO 2 C 6 H 12 O 6 O2O2 chlorophyll H2OH2OCO 2 C 6 H 12 O 6 O2O2

19 Photosynthesis Formula What’s wrong with this equation? The number of atoms is not equal on both sides of the equation. Balance the equation so that the number of atoms of each element is equal on both sides. H2OH2OCO 2 C 6 H 12 O 6 O2O2 one carbon atom reactant 6 carbon atoms product 6 66(1) Now balance it as if TWO glucose molecules were being produced.

20 Photosynthesis Review What goes in? (the reactants) What comes out? (the products) H2OH2O Light Reaction Dark Reaction CO 2 C 6 H 12 O 6 O2O2 chlorophyll 6CO 2 + 6H 2 O 6O 2 + C 6 H 12 O 6 light chlorophyll

21 How do cells make energy? Cellular Respiration

22 Cellular Respiration I. Cellular Respiration – the process by which glucose molecules are broken down to release energy Series of chemical reactions which produce ATP. There are 2 forms of cellular respiration. Mitochondria is the cell organelle where respiration occurs.

23 A. 2 Forms of Cellular Respiration: 1.Aerobic Respiration – requires oxygen & produces 36 ATP molecules 2.Anaerobic Respiration – does NOT require oxygen & produces 2 ATP molecules

24 Cellular Respiration What is cellular respiration? What is cellular respiration? Cellular respiration is the process by which: Cellular respiration is the process by which: water carbon dioxide oxygen glucose TAKE IN MAKE mitochondria ATP

25 Cellular Respiration Formula How would this be written as a chemical equation? What goes in? (the reactants) What comes out? (the products) H2OH2O CO 2 C 6 H 12 O 6 O2O2

26 Equation for Cellular Respiration C 6 H 12 O 6 + 6 O 2  6 CO 2 + 6 H 2 O + ATP mitochondria animal cells plant cells

27 Photosynthesis Cellular Respiration food synthesized food broken down energy from sun stored in glucose energy of glucose released carbon dioxide taken in carbon dioxide given off oxygen given off oxygen taken in produces sugars produces carbon dioxide and water requires light does not require light occurs only in presence of chlorophyll occurs in all living cells