Chapter 8 Cellular Energy

1. Chapter 8 Cellular Energy 8.1 Cells and the Flow of Energy 8.2 Metabolic Reactions and Energy Transformations 8.3 Metabolic Pathways and Enzymes

2. 8.1 How Organisms obtain energy • Objectives • Summarize two _________ of thermodynamics. • Compare and contrast __________________ and heterotrophs. • Describe how ATP works in a _______________.

3. Transformation of Energy • Energy: The ability to do _______________ • Thermodynamics: study of the flow & transformation of ____________________ in the universe.

4. Laws of Thermodynamics • Energy cannot be __________________ or destroyed, but it can be changed from one form to another. • Potential  Kinetic • Law of conservation of ____________________ • Energy cannot be changed from one form to another without a _____________ of usable energy. • Often times, it is lost in the form of _____________. (thermal)

5. Autotrophs & Heterotrophs • All organisms need energy • Nearly all energy for life comes from the __________ • Autotrophs make their own _______________. • Chemoautotrophs use inorganic substances for an energy source • ________________autotrophs use the sun • Heterotrophs need to ingest food (other organisms) to obtain __________________

6. Metabolism • Metabolism: all the ___________ reactions in a cell • Metabolic pathway: product from one becomes the __________________ for the next (all enzymatic!) • Catabolic: release energy, break down big molecules into ________________ ones • Anabolic: use ________________ energy by catabolic to build bigger molecules from smaller ones

7. Photosynthesis • Anabolic • Light energy + carbon dioxide + water  glucose + oxygen • Glucose can be __________________ to other organisms when consumed as food

8. Cellular Respiration • Catabolic • Organic molecules are _________________ down to release energy for use by the cell • Oxygen is used to break them down producing ________________________ and water

9. ATP: The Unit of Cellular Energy • Types of energy: mechanical, thermal, chemical, ____________ • Adenosine triphosphate: __________: is the most important biological molecule that provides chemical energy. • Adenine base, a ribose _______________, and three phosphate groups • Energy is stored in that phosphate bond and is released. ATPADP

10. 8.2 Photosynthesis • Objectives: • Summarize the two ___________________ of photosynthesis. • Explain the function of a ___________________ during the light reactions. • Describe and diagram __________________ transport.

11. Photosynthesis • Light energy converted to __________________ energy • 6CO2 + 6H2O  C6H12O6 + 6O2 • Two phases: • Light-_______________________: light e is absorbed and converted into chemical e in the form of ATP and NADPH • Light-__________________________ : ATP and NADPH are used to make glucose • Glucose can be joined to other simple carbs, such as starch. • Can also be made into proteins, lipids, and nucleic acids

12. Phase One: Light Reactions • Absorb light and make NADPH and ATP • Chloroplasts: capture __________________ in photosynthetic organisms • Mainly found in the cells of ________________ • Thylakoids: flattened saclike membranes that are arranged in ________________________. • Grana: the stacks • Light dependent _________________ take place in thylakoids • Stroma: fluid-filled space outside the grana • Light independent reactions take place in stroma

13. Pigments • Pigments: light-absorbing colored molecules found in the thylakoid _____________________ of chloroplasts • Chlorophylls are the major light-absorbing _______________________ in plants. • Chlorophyll a, chlorophyll bare the most common • Absorb most strongly in the violet-blue region and reflect green • Carotenoids: absorb in the ____________ and green regions and reflect in the yellow, orange, and red regions. • Fall colors are the result of chlorophyll molecules breaking down and allowing the other pigments to show through.

14. Electron Transport • Light energy absorbed by photosystem II is used to split water. Oxygen is released, protons (H+ ions) stay in the thylakoid space and an activated electron enters the electron transport ______________________. • As electrons move through the membrane, _____________ are pumped into the thylakoid space. • At photosystem I, electrons are re-energized and NADPH is formed. • Chemiosmosis: protons accumulate in the thylakoid space, creating a ____________________________ gradient. • When protons move across the thylakoid membrane through ATP synthase, ADP is converted to ATP.

16. Phase Two: The Calvin Cycle • NADPH and ATP are not stable enough to store energy for a ___________________________. • Carbon fixation: carbon ________________ combines with 5-carbon compounds to make 3-carbon molecules called 3-phosphoglycerate. • ATP and NADPH give their stored energy to form glyceraldehyde 3-phosphates. • Two glyceraldehydes leave to make _____________. • Rubisco (enzyme) converts the remaining G3P molecules back to 5-carbon molecules so that the cycle can continue.

18. Alternative Pathways • C4 plants • Minimizes water __________________ • Use four-carbon rather than three-carbon molecules • Stoma do not open on ___________________. Special cells take the carbon compounds so carbon dioxide can enter and photosynthesis can occur. • CAM plants • Occurs in plants that live in the _________________ (minimize water loss), salt marshes, and where water is minimal • Only open stoma at ______________. • During the day, carbon dioxide is released from these compounds and enters the Calvin cycle.

19. 8.3 Cellular Respiration • Objectives: • Summarize the stages of ___________________ respiration. • Identify the role of ____________________ carriers in each stage of cellular respiration. • Compare alcoholic fermentation and lactic _______________ fermentation.

20. Cellular Respiration • Two main parts: Glycolysis and aerobic respiration • Anaerobic processes: no ______________ required • Aerobic respiration: includes Krebs __________ and electron transport. • Aerobic processes require oxygen • Equation is the _____________ of photosynthesis

21. Glycolysis • Glucose is broken down in ________________ via glycolysis • First, two ATP are used to break _____________ into two G3P. • Then, each of these 3-carbon compounds give phosphates and H+ ions to produce 2 ATP and one NADH. • Result: 2 NADH and 4 ATP – 2 ATP = 2 ATPand two pyruvates for Krebs cycle

22. Krebs Cycle • Pyruvate converted to acetyl-CoA before cycle begins, ______________________released. • Pyruvates are transported to mitochondrial matrix in the presence of ___________________. • Acetyl-CoA combines with 4-carbon compound to make citric ___________________. • Citric acid broken down, releasing _________ carbon dioxides, one ATP, three NADH, and one FADH2. • Results in a four-carbon sugar that can combine with acetyl-CoA to turn it again.

23. Electron Transport • This is when NADH and FADH2 from the Krebs cycle convert ADP to ___________________. • Electrons move along the mitochondrial membrane through ________________________. • The NADH and FADH2 are converted to NAD+ and FAD, the H+ ___________________ released into m. matrix. • As H+ ions come back through ATP synthase, ADP is converted to ATP. • One molecule of glucose yields 36 ATP via cellular respiration.

24. Anaerobic Respiration • Aka fermentation. • Fermentation: occurs in the __________________ and regenerates the cell’s supply of NAD+ while making some _________________. • Lactic acid fermentation and alcohol fermentation are the two types • Lactic acid: skeletal _________________ produces lactic acid during strenuous exercise when not getting oxygen; results in cramping…eat bananas! • Alcohol: Yeast and some bacteria. Results in ethyl alcohol and carbon dioxide.

25. Sister Processes • The products from one reaction are the ____________________ for the other…photosynthesis and cellular respiration.