1. Cellular Energetics CHAPTER 5

2. Energy in Living Systems  Directly or indirectly, almost all of the energy in living systems needed for metabolism comes from the sun. Section 1 Energy and Living Things Chapter 5

3. Building Molecules That Store Energy  Metabolism :using energy to build molecules or breaking down molecules in which energy is stored  Photosynthesis :process by which light energy is converted to chemical energy  Autotrophs : Organisms that use energy from sunlight or from chemical bonds in inorganic substances to make organic compounds  Breaking Down Food for Energy  The chemical energy in organic compounds can be transferred to other organic compounds or to organisms that consume food.  Heterotrophs :Organisms that must get energy from food instead of directly from sunlight or inorganic substances  Cellular respiration : metabolic process similar to burning fuel. Section 1 Energy and Living Things Chapter 5

4. Breakdown of Starch Section 1 Energy and Living Things Chapter 5

5. cells break down food: 1.some of the energy in the molecules is released as heat 2.remaining energy is stored temporarily in molecules of ATP.  Like money, ATP is a portable form of energy “currency” inside cells.  ATP delivers energy wherever energy is needed in a cell.  Do you remember what ATP is? Section 1 Energy and Living Things Chapter 5

6. ATP  nucleotide with two extra energy-storing phosphate groups.  Energy is released when the bonds that hold the phosphate groups together are broken.  produces adenosine diphosphate, or ADP: H 2 O + ATP  ADP + P + energy Section 1 Energy and Living Things Chapter 5

7. Using the Energy in Sunlight The Stages of Photosynthesis  Stage 1 Energy is captured from sunlight.  Stage 2 Light energy is converted to chemical energy  which is temporarily stored in ATP and the energy carrier molecule NADPH.  Stage 3 The chemical energy stored in ATP and NADPH powers the formation of organic compounds  using carbon dioxide, CO 2. Section 2 Photosynthesis Chapter 5 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Carbon dioxide water sugars oxygen gas

8. Photosynthesis Section 2 Photosynthesis Chapter 5

9. Pigments  How does a human eye or a leaf absorb light?  These structures contain light-absorbing substances called pigments.  Chlorophyll primary pigment involved in photosynthesis absorbs mostly blue and red light and reflects green and yellow light.  Plants contain two types of chlorophyll, chlorophyll a and chlorophyll b. Section 2 Photosynthesis Chapter 5

10. Pigments  The pigments that produce yellow and orange fall leaf colors, as well as the colors of many fruits, vegetables, and flowers, are called carotenoids.  Carotenoids absorb wavelengths of light different from those absorbed by chlorophyll, so having both pigments enables plants to absorb more light energy during photosynthesis. Section 2 Photosynthesis Chapter 5

11. Absorption Spectra of Photosynthetic Pigments Section 2 Photosynthesis Chapter 5

12. Production of Oxygen  Clusters of pigments are embedded in the membranes of disk-shaped structures called thylakoids.  When light strikes a thylakoid in a chloroplast, energy is transferred to electrons in chlorophyll.  This energy transfer causes the electrons to jump to a higher energy level. This is how plants first capture energy from sunlight. Section 2 Photosynthesis Chapter 5

13. Production of Oxygen  excited electrons that leave chlorophyll molecules must be replaced  replacement electrons are from water molecules, which are split by thylakoid.  The oxygen atoms, O, from the disassembled water molecules combine to form oxygen gas, O 2 Section 2 Photosynthesis Chapter 5

14. Stage Two: Conversion of Light Energy  Excited electrons that leave chlorophyll molecules are used to produce new molecules that temporarily store chemical energy.  First an excited electron jumps to a nearby molecule in the thylakoid membrane. Then the electron is passed through a series of molecules along the thylakoid membrane.  The series of molecules through which excited electrons are passed along a thylakoid membrane are called electron transport chains. Section 2 Photosynthesis Chapter 5

15. Electron Transport Chains  While one electron transport chain provides energy used to make ATP, a second electron transport chain provides energy used to make NADPH.  NADPH is an electron carrier that provides the high-energy electrons needed to make carbon-hydrogen bonds in the third stage of photosynthesis.  In this second chain, excited electrons combine with hydrogen ions as well as an electron acceptor called NADP +, forming NADPH. Section 2 Photosynthesis Chapter 5

16. Converting Light Energy to Chemical Energy Section 2 Photosynthesis Chapter 5

17. Stage Three: Storage of Energy  In the third (final) stage of photosynthesis, carbon atoms from carbon dioxide in the atmosphere are used to make organic compounds in which chemical energy is stored.  The transfer of carbon dioxide to organic compounds is called carbon dioxide fixation. Section 2 Photosynthesis Chapter 5

18. Calvin Cycle  series of enzyme-assisted chemical reactions that produces a three- carbon sugar: Step 1 Each molecule of carbon dioxide is added to a five-carbon compound by an enzyme. Step 2 The resulting compound splits into two three-carbon compounds. Phosphate groups and electrons are added to the compounds. Step 3 One of the resulting three- carbon sugars is used to make organic energy-storing compounds. Section 2 Photosynthesis Chapter 5 Step 4 The other three-carbon sugars are used to regenerate the initial five-carbon compound, thereby completing the cycle.

19. Turn to a neighbor and discuss what factors you think might make photosynthesis occur at higher or lower rates

20. Stage Three: Storage of Energy, continued Factors that Affect Photosynthesis  Photosynthesis is directly affected by various environmental factors.  In general, the rate of photosynthesis increases as light intensity increases until all the pigments are being used.  Photosynthesis is most efficient within a certain range of temperatures. Section 2 Photosynthesis Chapter 5

21. Cellular Energy 2 Types of cellular Respiration AEROBIC:  Metabolic processes that require oxygen ANAEROBIC:  Metabolic processes that do not require oxygen anaerobic: means “without air.” Section 3 Cellular Respiration Chapter 5

22. Cellular Energy, continued Aerobic Cellular Respiration process cells use to harvest the energy in organic compounds, particularly glucose can be summarized by the following equation: C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy glucose oxygen gas carbon dioxide water ATP What does this equation remind you of? Section 3 Cellular Respiration Chapter 5

23. Cellular Energy, continued 2 Stages of Cellular Respiration Stage 1 Glucose is converted to pyruvate producing a small amount of ATP and NADH. Stage 2 In the presence of oxygen, pyruvate and NADH are used to make a large amount of ATP When oxygen is not present, pyruvate is converted to either lactate or ethanol and carbon dioxide. Section 3 Cellular Respiration Chapter 5

24. COPY THIS DIAGRAM

25. Cellular Respiration Section 3 Cellular Respiration Chapter 5

26. Stage One: Breakdown of Glucose 1. Glycolysis glucose is broken down in the cytoplasm (LOCATION LOCATION LOCATION) some of its hydrogen atoms are transferred to an electron acceptor called NAD + This forms an electron carrier called NADH. Section 3 Cellular Respiration Chapter 5

27.  Glycolysis occurs in four steps: Step 1 Phosphate groups from two ATP are transferred to glucose Step 2 six-carbon compound is broken down two three-carbon compounds. Step 3 Two NADH molecules are produced Step 4 Each three-carbon compound is converted to a three-carbon pyruvate, producing four ATP molecules in the process. Net ATP production of this stage? Section 3 Cellular Respiration Chapter 5

28. Stage Two: Production of ATP  Aerobic: pyruvate produced during glycolysis enters a mitochondrion (LOCATION!!!) and is converted to a two-carbon compound.  produces one carbon dioxide molecule, one NADH molecule, and one two-carbon acetyl group.  acetyl group is attached to a  molecule called coenzyme A (CoA),  forming acetyl-CoA.

29. Krebs Cycle 5 Steps: Step 1 Acetyl-CoA combines with a four-carbon compound, forming a six-carbon compound and releasing coenzyme A. Step 2 Carbon dioxide is released from the six-carbon compound, forming a five-carbon compound. Electrons are transferred to NAD +, making a molecule of NADH. Over 95% of the energy used by moving cells in the human body is generating by the Krebs cycle and other linked processes citric acid cycle is a series of chemical reactions necessary to produce energy from food. No energy, no muscle movement, no organ function...no aerobic life would exist without it. This critical process is also known as the Krebs cycle or tricarboxylic acid (TCA) cycle, and is the central metabolic and biochemical hub of the cell.

30. Krebs Cycle Step 3 Carbon dioxide is released; molecule of ATP and a molecule of NADH are made. Step 4 The existing four-carbon compound is converted to a new four-carbon compound. Electrons are transferred to an electron acceptor called FAD, making a molecule of FADH 2, another type of electron carrier. Step 5 The new four-carbon compound is then converted to the four-carbon compound that began the cycle. Another molecule of NADH is produced. Section 3 Cellular Respiration Chapter 5

31. Stage Two: Production of ATP, continued Electron Transport Train  aerobic respiration, electrons donated by NADH and FADH 2 pass through an electron transport chain.  In eukaryotic cells, the electron transport chain is located in the inner membranes of mitochondria.  At the end of the electron transport chain, hydrogen ions and spent electrons combine with oxygen molecules forming water molecules. Section 3 Cellular Respiration Chapter 5

32. Electron Transport Chain of Aerobic Respiration Section 3 Cellular Respiration Chapter 5

33. ANAEROBIC Respiration  NAD + is recycled in another way.  electrons carried by NADH are transferred to pyruvate produced during glycolysis.  The recycling of NAD + using an organic hydrogen acceptor is called fermentation. Section 3 Cellular Respiration Chapter 5 Fermentation enables glycolysis to continue producing ATP in muscles as long as the glucose supply lasts.

34. Alcoholic Fermentation  In some organisms, the three-carbon pyruvate is broken down to ethanol (ethyl alcohol), a two-carbon compound, through alcoholic fermentation.  NAD + is recycled, and glycolysis can continue to produce ATP. Section 3 Cellular Respiration Chapter 5

35. Section 3 Cellular Respiration Chapter 5

36. Section 3 Cellular Respiration Chapter 5

37. Cellular Respiration Versus Fermentation Section 3 Cellular Respiration Chapter 5

39. Multiple Choice The chart below shows data on photosynthesis in one type of plant. Use the chart to answer questions 1–3. Standardized Test Prep Chapter 5

40. 1. Which statement is supported by the data? A.Photosynthesis does not occur at 0°C. B.The optimum temperature for photosynthesis is approximately 46°C. C.The rate of photosynthesis at 40°C is greater than the rate at 20°C. D.The rate of photosynthesis increases as temperature increases from 25°C to 30°C. Standardized Test Prep Chapter 5

41. Multiple Choice, continued 2. At approximately what temperature is the plant producing oxygen at the greatest rate? F.0°C G.23°C H.46°C J.50°C Standardized Test Prep Chapter 5

42. Multiple Choice, continued 2. At approximately what temperature is the plant producing oxygen at the greatest rate? F.0°C G.23°C H.46°C J.50°C Standardized Test Prep Chapter 5

43. Multiple Choice, continued 3. Data obtained from a different type of plant show a similar relationship between rate of photosynthesis and temperature, but the curve is shifted to the right. What environment would this plant be best adapted to? A.Cold subarctic environment B.Cool, wet environment C.Mild, dry environment D.Hot equatorial environment Standardized Test Prep Chapter 5