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Photosynthesis and Respiration

Photosynthesis and Respiration. Honors Supplement. Remember the Light Spectrum?. In the spectrum of energy waves, the visible spectrum is a small section in which different colors have different wavelengths. Although Red light has the longest wavelength, it has the least energy ~700-750nm

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Photosynthesis and Respiration

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  1. Photosynthesis and Respiration Honors Supplement

  2. Remember the Light Spectrum? • In the spectrum of energy waves, the visible spectrum is a small section in which different colors have different wavelengths

  3. Although Red light has the longest wavelength, it has the least energy • ~700-750nm • Violet light has the shortest wavelength, therefore, it has the most energy • ~380-400nm • ROY G BIV

  4. Pigments • Plants gather the sun’s energy with light absorbing molecules calledpigments • The plant’s principal pigment ischlorophyll

  5. Two Kinds of Chlorophyll • Chlorophyll aabsorbs light best in the red region • Chlorophyll babsorbs light best in the blue region • Neither chlorophyll absorbs light very well in the green region

  6. CO2 Light NADP+ ADP + P Calvin Cycle Light- Dependent Reactions ATP NADPH Sugars O2

  7. Light-Dependent Rxns • Light energy is absorbed by pigments in Photosystem II and the electrons in the pigments become high-energy electrons • These electrons are passed on to an electron transport chain (ETC) in the thylakoid membrane

  8. High energy electrons move through the ETC from photosystem II (PSII) to photosystem I (PSI) • PSI uses energy from the sun to reenergize the electrons • These electrons move down the ETC and NADP+ then picks them upfor later use

  9. Does photosystem II ever run out of electrons? • Water molecules are broken into 2 electrons, 2 protons (H+), and oxygen • These two electrons replace the electrons that went to the ETC • The oxygen is released as O2 • The 2 H+ ions are released inside the thylakoid membrane

  10. The concentration of H+ inside the thylakoid is great enough to drive the production of ATP via ATP synthase

  11. Respiration Chapter 9

  12. Energy and Living Things

  13. ENERGY FOR CELLS Where do cells get their energy? How do cells get energy?

  14. TWO TYPES OF CHEMICAL REACTIONS • Endergonic – energy is absorbed. Energy of the products is greater than the energy of the reactants. Uphill

  15. Exergonic – Energy is released. Energy of the products is less than the energy of the reactants. Downhill

  16. Endergonic Reaction • X-axis=time • Y-axis=energy • Still requires activation energy P R

  17. Exergonic Reaction • X-axis=time • Y-axis=energy • Still requires activation energy R P

  18. ATP • Adenosine TriPhosphate • It is the major energy currency of the cell • It is made of a nitrogen base (adenine), a sugar (ribose), and three phosphate groups

  19. When the third phosphate group of ATP is removed by hydrolysis, a large amount of energy is released. • Hydrolysis = when a molecule is broken down by adding water

  20. ATP + H2O ADP + Pi • ADPis Adenosine DiPhosphate. • Pi is inorganic phosphate

  21. Your body can use the energy released from breaking the 3rd phosphate bond of ATP to do work. • The amount of energy given off from ATP is the perfect amount for cells. • Your body can also make ATP from ADP.

  22. CELLULAR RESPIRATION • Cellular respiration is the process by which the chemical energy of "food" molecules is partially transferred to ATP. • Breaking down food for energy.

  23. Lipids, proteins, fats, and carbohydrates can be broken down for energy. • Our focus is on glucose.

  24. Two types of respiration: • Aerobic– uses oxygen • Occurs in the mitochondria • Anaerobic– uses no oxygen (also called fermentation) • Occurs in the cytoplasm

  25. AEROBIC RESPIRATON • The energy in the chemical bonds of glucose is partially transferred to ADP to makeATP. • 60% of the energy from glucose is “lost” as heat.

  26. Glucose is broken down. • Oxygenis needed to completely break down glucose. • Carbon dioxide is released. Oxygen + GlucoseCO2 + water + energy

  27. Glycolysis • The first set of reactions in cellular respiration is Glycolysis • Glycolysis is the process in which 1 molecule of glucose (C6) is broken in half, producing two molecules of pyruvic acid (C3) • Glycolysis occurs in the cytoplasm

  28. Glucose ATP 2 2 ADP 4 ADP 2 NAD+ 4 ATP 2 NADH 2 Pyruvic Acid

  29. ATP Production • Glycolysis is an energy-releasing process, but the cell needs to invest a little energy to get things started • 2 ATPs are needed to get glycolysis started, but at the end 4 ATPs are produced • Since we already invested 2 ATP, we have a net gain of 2 ATP

  30. NADH Production • One of the reactions in glycolysis removes high energy electrons from each 3 carbon molecule and passes them to an electron carrier, NAD+ • NAD+ hold on to the electrons until it can pass them to other molecules within the mitochondria

  31. The Krebs Cycle • After glycolysis, about 90% of the chemical energy of glucose is still trapped in the high-energy electrons of pyruvic acid • During the Krebs cycle, pyruvic acid is broken down and carbon dioxide is released • The Krebs cycle occurs in the mitochondria

  32. The Krebs cycle begins when pyruvic acid enters the mitochondrion and is changed to another molecule • Pyruvic acid joins with a compound called Coenzyme-A to make acetyl-CoA • CO2 is given off • Acetyl-CoA joins with a 4 carbon molecule to make citric acid (6C)

  33. Pyruvic Acid NAD+ CO2 NADH Co-A Co-A Co-A Citrate

  34. Citric Acid NAD+ NADH CO2 FAD NAD+ FADH2 NADH 4 Carbon Compound 5 Carbon Compound ADP NAD+ CO2 ATP NADH

  35. Electron Transport • The Electron Transport Chain (ETC) is a series of proteins in the inner mitochondrial membrane that pass along the high energy electrons of NADH and FADH2 • These high-energy electrons are used by the ETC to convert ADP to ATP

  36. How ATPs are Made • NADH and FADH2 bring their high energy electrons to specific proteins within the inner mitochondrial membrane • These special proteins are arranged in a line and make up the Electron Transport Chain

  37. What’s the Point? • At the end of every ETC there is a special enzyme called ATP synthase • The H+ diffuse through the ATP synthase creating enough energy to add a phosphate to ADP to make ATP

  38. What about our electrons? • At the end of the ETC the electrons need a place to go • Oxygen is the final electron acceptor which accepts two electrons and 2 H+ per oxygen atom • The point? No oxygen, no Krebs cycle

  39. This oxygen is the oxygen that we breathe in every time we take a breath

  40. WHOA! • This means that for each molecule of glucose you can make a maximum of 38 ATPs

  41. ANAEROBIC RESPIRATION (FERMENTATION) • In many cells, if oxygen isnotpresent, glucose is broken down in a process called fermentation.

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