Table of Contents – pages iv-v Unit 1:What is Biology? Unit 2:Ecology Unit 3:The Life of a Cell Unit 4:Genetics Unit 5:Change Through Time Unit 6:Viruses, Bacteria, Protists, and Fungi Unit 7:Plants Unit 8:Invertebrates Unit 9:Vertebrates Unit 10:The Human Body
Table of Contents – pages iv-v Unit 1: What is Biology? Chapter 1:Biology: The Study of Life Unit 2: Ecology Chapter 2:Principles of Ecology Chapter 3:Communities and Biomes Chapter 4:Population Biology Chapter 5:Biological Diversity and Conservation Unit 3:The Life of a Cell Chapter 6:The Chemistry of Life Chapter 7:A View of the Cell Chapter 8:Cellular Transport and the Cell Cycle Chapter 9:Energy in a Cell
Unit 4: Genetics Chapter 10:Mendel and Meiosis Chapter 11:DNA and Genes Chapter 12:Patterns of Heredity and Human Genetics Chapter 13:Genetic Technology Unit 5: Change Through Time Chapter 14:The History of Life Chapter 15:The Theory of Evolution Chapter 16:Primate Evolution Chapter 17:Organizing Life’s Diversity Table of Contents – pages iv-v
Unit 6: Viruses, Bacteria, Protists, and Fungi Chapter 18:Viruses and Bacteria Chapter 19:Protists Chapter 20:Fungi Unit 7: Plants Chapter 21:What Is a Plant? Chapter 22:The Diversity of Plants Chapter 23:Plant Structure and Function Chapter 24:Reproduction in Plants Table of Contents – pages iv-v
Table of Contents – pages iv-v Unit 8: Invertebrates Chapter 25:What Is an Animal? Chapter 26:Sponges, Cnidarians, Flatworms, and Roundworms Chapter 27:Mollusks and Segmented Worms Chapter 28:Arthropods Chapter 29:Echinoderms and Invertebrate Chordates
Table of Contents – pages iv-v Unit 9: Vertebrates Chapter 30:Fishes and Amphibians Chapter 31:Reptiles and Birds Chapter 32:Mammals Chapter 33:Animal Behavior Unit 10: The Human Body Chapter 34:Protection, Support, and Locomotion Chapter 35:The Digestive and Endocrine Systems Chapter 36:The Nervous System Chapter 37:Respiration, Circulation, and Excretion Chapter 38:Reproduction and Development Chapter 39:Immunity from Disease
Unit Overview – pages 138-139 The Life of a Cell The Chemistry of Life A View of the Cell Cellular Transport and the Cell Cycle Energy in a Cell
Chapter Contents – page viii Chapter 9Energy in a Cell 9.1:The Need for Energy 9.1:Section Check 9.2:Photosynthesis: Trapping the Sun’s Energy 9.2:Section Check 9.3:Getting Energy to Make ATP 9.3:Section Check Chapter 9Summary Chapter 9Assessment
Chapter Intro-page 220 What You’ll Learn You will recognize why organisms need a constant supply of energy and where that energy comes from. You will identify how cells store and release energy as ATP. You will describe the pathways by which cells obtain energy.
Chapter Intro-page 220 What You’ll Learn You will compare ATP production in mitochondria and in chloroplasts.
9.1 Section Objectives – page 221 Section Objectives: • Explain why organisms need a supply of energy. • Describe how energy is stored and released by ATP.
Section 9.1 Summary – pages 221-224 Cell Energy • All living organisms must be able to obtain energy from the environment in which they live. • Plants and other green organisms are able to trap the light energy in sunlight and store it in the bonds of certain molecules for later use.
Section 9.1 Summary – pages 221-224 Cell Energy • Other organisms cannot use sunlight directly. • They eat green plants. In that way, they obtain the energy stored in plants.
Section 9.1 Summary – pages 221-224 Work and the need for energy • Active transport, cell division, movement of flagella or cilia, and the production, transport, and storage of proteins are some examples of cell processes that require energy. • There is a molecule in your cells that is a quick source of energy for any organelle in the cell that needs it.
Section 9.1 Summary – pages 221-224 Work and the need for energy • The name of this energy molecule is adenosine triphosphate or ATP for short. • ATP is composed of an adenosine molecule with three phosphate groups attached.
Section 9.1 Summary – pages 221-224 Forming and Breaking Down ATP • The charged phosphate groups act like the positive poles of two magnets. • Bonding three phosphate groups to form adenosine triphosphate requires considerable energy.
Section 9.1 Summary – pages 221-224 Forming and Breaking Down ATP • When only one phosphate group bonds, a small amount of energy is required and the chemical bond does not store much energy. This molecule is called adenosine monophosphate (AMP). • When a second phosphate group is added, more energy is required to force the two groups together. This molecule is called adenosine diphosphate, or ADP.
Section 9.1 Summary – pages 221-224 Forming and Breaking Down ATP • An even greater amount of energy is required to force a third charged phosphate group close enough to the other two to form a bond. When this bond is broken, energy is released.
Section 9.1 Summary – pages 221-224 Forming and Breaking Down ATP • The energy of ATP becomes available to a cell when the molecule is broken down. P P P Adenosine Adenosine triphosphate (ATP) P P Adenosine diphosphate (ADP) P P Adenosine
Section 9.1 Summary – pages 221-224 How cells tap into the energy stored in ATP • When ATP is broken down and the energy is released, the energy must be captured and used efficiently by cells. • Many proteins have a specific site where ATP can bind.
Section 9.1 Summary – pages 221-224 How cells tap into the energy stored in ATP • Then, when the phosphate bond is broken and the energy released, the cell can use the energy for activities such as making a protein or transporting molecules through the plasma membrane. ATP Protein P Energy ADP ADP
Section 9.1 Summary – pages 221-224 How cells tap into the energy stored in ATP • When ATP has been broken down to ADP, the ADP is released from the binding site in the protein and the binding site may then be filled by another ATP molecule.
Section 1 Check Question 1 What is the primary difference in the ways that plants and animals obtain energy? Answer All living organisms need energy. Plants can trap light energy in sunlight and store it for later use. Animals cannot trap energy from sunlight and must eat plants that contain stored energy. NC: 4.02
Section 1 Check Question 2 Why does the formation of ATP require energy? NC: 4.02
Section 1 Check One molecule of ATP contains three phosphate groups, which are charged particles. Energy is required to bond the phosphate groups onto the same molecule because they behave the same way that the poles of magnets do and repel groups with like charges. When the ATP molecule is broken down, the chemical energy stored in it becomes available to the cell for life processes. NC: 4.02
Section 1 Check Question 3 A molecule of adenosine that has one phosphate group bonded to it is ______. A. AMP B. ADP C. ATP D. ACP NC: 4.02
Section 1 Check The answer is A. AMP is adenosine monophosphate. P P P Adenosine The addition and release of a phosphate group on adenosine diphosphate creates a cycle of ATP formation and breakdown. Adenosine triphosphate (ATP) P P Adenosine diphosphate (ADP) P P Adenosine NC: 4.02
Section 1 Check Question 4 What is the function of the protein molecule shown in this diagram? ATP Energy Protein P ADP ADP NC: 4.02
Section 1 Check This protein molecule has a specific binding site for ATP. In order to access the energy stored ATP, the protein molecule binds the ATP and uncouples one phosphate group. This action releases energy that is then available to the cell. ATP Protein Energy P ADP ADP NC: 4.02
9.2 Section Objectives – page 225 Section Objectives: • Relate the structure of chloroplasts to the events in photosynthesis. • Describe light-dependent reactions. • Explain the reactions and products of the light-independent Calvin cycle.
Section 9.2 Summary – pages 225-230 Trapping Energy from Sunlight • The process that uses the sun’s energy to make simple sugars is called photosynthesis.
Section 9.2 Summary – pages 225-230 Trapping Energy from Sunlight • Photosynthesis happens in two phases. • The light-dependent reactions convert light energy into chemical energy. 2. The molecules of ATP produced in the light-dependent reactions are then used to fuel the light-independent reactions that produce simple sugars. • The general equation for photosynthesis is written as 6CO2 + 6H2O→C6H12O6 + 6O2
Section 9.2 Summary – pages 225-230 Trapping Energy from Sunlight Click image to view movie.
Section 9.2 Summary – pages 225-230 The chloroplast and pigments • To trap the energy in the sun’s light, the thylakoid membranes contain pigments, molecules that absorb specific wavelengths of sunlight. • Although a photosystem contains several kinds of pigments, the most common is chlorophyll. • Chlorophyll absorbs most wavelengths of light except green.
Section 9.2 Summary – pages 225-230 Light-Dependent Reactions • As sunlight strikes the chlorophyll molecules in a photosystem of the thylakoid membrane, the energy in the light is transferred to electrons. • These highly energized, or excited, electrons are passed from chlorophyll to an electrontransport chain, a series of proteins embedded in the thylakoid membrane.
Section 9.2 Summary – pages 225-230 Sun Light-Dependent Reactions Light energy transfers to chlorophyll. • At each step along the transport chain, the electrons lose energy. Chlorophyll passes energy down through the electron transport chain. Energized electrons provide energy that splits H2O to ADP bonds P forming ATP oxygen released H+ NADP+ NADPH for the use in light-independent reactions
Section 9.2 Summary – pages 225-230 Light-Dependent Reactions • This “lost” energy can be used to form ATP from ADP, or to pump hydrogen ions into the center of the thylakoid disc. • Electrons are re-energized in a second photosystem and passed down a second electron transport chain.
Section 9.2 Summary – pages 225-230 Light-Dependent Reactions • The electrons are transferred to the stroma of the chloroplast. To do this, an electron carrier molecule called NADP is used. • NADP can combine with two excited electrons and a hydrogen ion (H+) to become NADPH. • NADPH will play an important role in the light-independent reactions.
Section 9.2 Summary – pages 225-230 Restoring electrons • To replace the lost electrons, molecules of water are split in the first photosystem. This reaction is called photolysis. Sun _ 1 O2 + 2H+ Chlorophyll 2 2e- _ 1 O2+ 2e- H2O ®2H++ H2O 2
Section 9.2 Summary – pages 225-230 Restoring electrons • The oxygen produced by photolysis is released into the air and supplies the oxygen we breathe. • The electrons are returned to chlorophyll. • The hydrogen ions are pumped into the thylakoid, where they accumulate in high concentration.
(CO2) Section 9.2 Summary – pages 225-230 (CO2) The Calvin Cycle (Unstable intermediate) (RuPB) ADP + ATP ATP ADP + NADPH NADP+ (PGAL) (PGAL) (PGAL) (Sugars and other carbohydrates)
Section 9.2 Summary – pages 225-230 The Calvin Cycle • Carbon fixation The carbon atom from CO2 bonds with a five-carbon sugar called ribulose biphosphate (RuBP) to form an unstable six-carbon sugar. (CO2) • The stroma in chloroplasts hosts the Calvin cycle. (RuBP)
Section 9.2 Summary – pages 225-230 The Calvin Cycle • Formation of 3-carbon molecules The six-carbon sugar formed in Step A immediately splits to form two three-carbon molecules. (Unstable intermediate)
Section 9.2 Summary – pages 225-230 The Calvin Cycle • Use of ATP and NADPH A series of reactions involving ATP and NADPH from the light-dependent reactions converts the three-carbon molecules into phosphoglyceraldehyde (PGAL), three-carbon sugars with higher energy bonds. ATP ADP + NADPH NADP+ (PGAL)
Section 9.2 Summary – pages 225-230 The Calvin Cycle • Sugar production One out of every six molecules of PGAL is transferred to the cytoplasm and used in the synthesis of sugars and other carbohydrates. After three rounds of the cycle, six molecules of PGAL are produced. (PGAL) (Sugars and other carbohydrates)
Section 9.2 Summary – pages 225-230 The Calvin Cycle • RuBP is replenished Five molecules of PGAL, each with three carbon atoms, produce three molecules of the five-carbon RuBP. This replenishes the RuBP that was used up, and the cycle can continue. P ADP+ ATP (PGAL)
Section 2 Check Question 1 The process that uses the sun’s energy to make simple sugars is ________. A. cellular respiration B. glycolysis C. photosynthesis D. photolysis NC: 4.02
Section 2 Check The answer is C. Photosynthesis happens in two phases to make simple sugars and convert the sugars into complex carbohydrates for energy storage. NC: 4.02
Section 2 Check Question 2 The function accomplished by the light-dependent reactions is ________. A. energy storage B. sugar production C. carbon fixation D. conversion of sugar to PGAL NC: 4.02