Photosynthesis vs. Respiration

1. Photosynthesis vs. Respiration

2. Free Energy – • Enthalpy(heat of reaction) is the amount of energy released or absorbed during a chemical reaction • Symbol is ΔH • Think of it as energy needed • Entropy is a measure of randomness, tendency toward disorder • Symbol is ΔS • More disorder = more entropy • If reaction leads to more disorder, the entropy change (ΔS) is positive, if it becomes more ordered, ΔS is negative • Example: melting ice, condensing water, cleaning your room (+,-,-) • Temperature – T measured in K (273 + ºC) • Free Energy – spontaneity of a reaction • Spontaneous - is negative • Not spontaneous - is positive. Would be spontaneous if reversed.

3. Things in Common • Both photosynthesis and respiration make ATP. • Both involve, CO2, oxygen, sugar (C6H12O6), and water (H2O) • Almost all cells go through respiration

4. phosphate removed • Energy is released when a phosphate group is removed. • ATP transfers energy from the breakdown of food molecules to cell functions. • ADP is changed into ATP when a phosphate group is added.

5. adenosine triphosphate tri=3 adenosine diphosphate di=2 Organisms break down carbon-based molecules to produce ATP. • Carbohydrates are the molecules most commonly broken down to make ATP. • not stored in large amounts • up to 36 ATP from one glucose molecule

6. 80 percent of the energy in your body • about 146 ATP from a triglyceride • Fats store the most energy. • Proteins are least likely to be broken down to make ATP. • amino acids not usually needed for energy • about the same amount of energy as a carbohydrate

7. take place in thylakoids • water and sunlight are needed • chlorophyll absorbs energy • energy is transferred along thylakoid membrane then to light-independent reactions • oxygen is released • The light-dependent reactions capture energy from sunlight.

8. take place in stroma (fluid outside the thylakoids) • needs carbon dioxide from atmosphere • use energy to build a sugar in a cycle of chemical reactions • The light-independent reactions make sugars.

9. chlorophyll absorbs energy from sunlight • energized electrons enter electron transport chain • water molecules are split • oxygen is released as waste • hydrogen ions are transported across thylakoid membrane • Photosystem II captures and transfers energy.

10. chlorophyll absorbs energy from sunlight • energized electrons are used to make NADPH • NADPH is transferred to light-independent reactions • Photosystem I captures energy and produces energy-carrying molecules.

11. Summary of Light Dependent Reactions • Energy is captured from the sun. • Energy goes into electrons into the electron transport chain. • Water is broken down • H+ ions are transported and form NADPH • Flow of H+ ions through ATP synthase makes ATP • Electron Transport

12. Summary of Light Independent Reactions (Calvin Cycle) • CO2 enters cycle • ATP and NADPH from light-dependent transfer energy • 1 3-carbon molecule made for every 3 CO2 • 2 3-carbon molecules bonded to make sugar • Products – 6-carbon sugar, NADP+, and ADP

13. carbon dioxide molecules enter the Calvin cycle (this is what has sugar as an end product • energy is added and carbon molecules are rearranged • a high-energy three-carbon molecule leaves the cycle • A molecule of glucose is formed as it stores some of the energy captured from sunlight.

14. A molecule of glucose is formed as it stores some of the energy captured from sunlight. • remaining molecules stay in the cycle • two three-carbon molecules bond to form a sugar

15. mitochondrion animal cell Cellular respiration makes ATP by breaking down sugars. • Cellular respiration is aerobic, or requires oxygen. • Aerobic stages take place in mitochondria.

16. anaerobic process (does not require oxygen) • takes place in cytoplasm • splits glucose into two three-carbon molecules • produces two ATP molecules • Glycolysis must take place first.

17. 1 ATP mitochondrion matrix (area enclosed by inner membrane) and 6CO 2 energy 2 3 energy from glycolysis ATP inner membrane and and 6H O 6O 2 2 4 Cellular respiration is like a mirror image of photosynthesis. Krebs Cycle • The Krebs cycle transfers energy to an electron transport chain. • takes place inmitochondrial matrix • breaks down three-carbonmolecules from glycolysis • makes a small amount of ATP • releases carbon dioxide • transfers energy-carrying molecules

18. 1 ATP mitochondrion matrix (area enclosed by inner membrane) and 6CO 2 energy 2 Electron Transport 3 energy from glycolysis ATP inner membrane and and 6H O 6O 2 2 4 • The electron transport chain produces a large amount of ATP. • takes place in inner membrane • energy transferred to electron transport chain • oxygen enters process • ATP produced • water released as awaste product

19. The Krebs cycle is the first main part of cellular respiration. • Pyruvate is broken down before the Krebs cycle. • carbon dioxide released • NADH produced • coenzyme A (CoA) bonds to two-carbon molecule

20. The Krebs cycle produces energy-carrying molecules.

21. The electron transport chain is the second main part of cellular respiration. • The electron transport chain uses NADH and FADH2 to make ATP. • high-energy electrons enter electron transport chain • energy is used to transport hydrogen ions across the inner membrane • hydrogen ionsflow through achannel in themembrane

22. The electron transport chain is the second main part of cellular respiration. • The electron transport chain uses NADH and FADH2 to make ATP. • The breakdown of one glucose molecule produces up to36 molecules of ATP. (2 from glycolysis, 2 from Kreb, 32 from ETC) • ATP synthase produces ATP • oxygen picks up electrons and hydrogen ions • water is released as a waste product

23. ATP Products of Cellular Respiration including glycolysis • Glycolysis – uses 2 ATP and make 4 ATP. Net gain of 2 ATP • Kreb Cycle – 2 ATP, 8 NADH, 2 FADH2 • Electron Transport Chain – 32ATP • Net gain – 36 ATP for every glucose molecule.

24. Comparison of Photosynthesis & Cellular Respiration

25. Fermentation allows glycolysis to continue when oxygen is unavailable. • Fermentation is an anaerobic process. • occurs when oxygen is not available for cellular respiration • does not produce ATP

26. NAD+ is recycled to glycolysis • Lactic acid fermentation occurs in muscle cells. • glycolysis splits glucose into two pyruvate molecules • pyruvate and NADH enter fermentation • energy from NADH converts pyruvate into lactic acid • NADH is changed back into NAD+ • Fermentation allows glycolysis to continue making ATP when oxygen is unavailable.

27. yogurt • cheese • Fermentation is used in food production. • bread

28. Project • In teams of 2, students will create a visual representation (e.g., poster or PowerPoint) to explain the interdependent relationships of cellular respiration and photosynthesis, and how the processes of cellular respiration and photosynthesis affect a runner in a marathon race. • Students should use few words and focus on using graphics to represent the cyclic processes. Visual representations will be peer and teacher reviewed.