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Photosynthesis

Photosynthesis. Energy and Life. Nearly every activity in modern society depends on Energy…think about it. Driving a car! Typing a paper! Using your IPOD! Talking on your cell phone! Living things also require ENERGY !. Where does that Energy come from?. Autotrophs (AKA: Producers)

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Photosynthesis

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  1. Photosynthesis

  2. Energy and Life • Nearly every activity in modern society depends on Energy…think about it. • Driving a car! • Typing a paper! • Using your IPOD! • Talking on your cell phone! • Living things also require ENERGY!

  3. Where does that Energy come from? • Autotrophs (AKA: Producers) • Use the sunlight as their ENERGY source. Heterotrophs (AKA: Consumers) • Obtain energy from the plants or other organisms that they consume.

  4. Chemical Energy • Candles burn • What does that mean? • Wax molecules store energy in the bonds between the hydrogens and carbons

  5. Electrons move from higher energy levels to lower energy levels. • Heat and light energy are released.

  6. Living things use and store energy

  7. Plants store energy as sugar or starch

  8. Animals store energy as glycogen (animal starch)

  9. Or as fat

  10. ATP: Adenosine Triphosphate • Adenine • Ribose:5 carbon sugar • 3 phosphate groups

  11. Storing Energy • ADP (adenosine diphosphate) is a compound that looks like ATP except it is lacking a __________ group. • This one difference is the key to the way in which living things store energy. Phosphate

  12. Storing Energy (cont.) • When a cell has energy available, it can store small amounts of it by adding a phosphate group to ADP, producing ATP. • Think of ATP as a fully charged battery and ADP as only a partially charged battery. • Now that we have Energy stored…how do we release it?.... http://www.biologyinmotion.com/atp/index.html

  13. Releasing Energy • Energy that is stored in ATP is released by breaking the chemical bond between the second and third phosphates.

  14. What the energy in ATP can do • Active transport • Protein synthesis • Muscle contraction

  15. What the energy in ATP can do • Synthesis of nucleic acids • Move organelles throughout the cell • Responds to chemical signals of cell • Fireflies!

  16. Question????? • Do you think cells have an abundant amount of ATP? • Answer: Most cells have only a small amount of ATP, enough to last them for a few seconds of activity. • Why? • Answer: ATP is great for transferring Energy, not for storing Energy.

  17. ATP Wrap-UP • Long term storage is done by other molecules, such as glucose, glycogen, starch • ATP can be regenerated by the cell over and over again • ADP + Energy + P → ATP • Required energy comes from food molecules

  18. 8-2:Overview of Photosynthesis • Van Helmont’s Experiment • Plants gain mass from water • Priestley • Plants produce oxygen • Jan Ingenhousz • Light is necessary

  19. 8-2:Overview of Photosynthesis • Photosynthesis converts light energy into the chemical energy of sugar and other organic compounds. • Light energy drives the reactions • O2- byproduct and is released into atmosphere

  20. The Photosynthetic Equation

  21. Light and Pigments • Pigments: light absorbing molecules • Chlorophyll absorbs blue-violet and red light • When a pigment absorbs light, it absorbs the energy from that light • Energy excites electrons

  22. 8-3: The Reactions of Photosynthesis • Where does photosynthesis take place? Chloroplasts!

  23. Parts of the chloroplasts • Thylakoids-Proteins in the thylakoid membrane organize chlorophyll and other pigments into clusters known as photosystems.

  24. Parts of the chloroplasts • Photosystems-light collecting units • Reactions of photosystems in 2 parts: • Light-dependent reactions(take place in thylakoid membrane) • Light-independent reactions(take place in the stroma)

  25. Light-Dependent Reactions • The light-dependent reactions produce oxygen gas and convert ADP and NADP+ into ATP and NADPH. • Occur in the thylakoid

  26. Calvin Cycle (light-independent) • The Calvin Cycle uses ATP and NADPH from the light-dependent reactions to produce high-energy sugars. • It takes carbon dioxide from the atmosphere and converts it into high-energy sugars that can be used to meet the plant’s energy needs and to build more complex molecules.

  27. What does all of that mean? • The two sets of photosynthetic reactions work together… • The light-dependent reactions trap the energy of sunlight in chemical form • The light-independent (Calvin cycle) uses that chemical energy to produce stable, high-energy sugars from carbon dioxide and water.

  28. Factors Affecting Photosynthesis • Shortage of water can slow down or stop photosynthesis • Plants have adaptations to reduce water loss: waxy coating on plants in dry areas. • Temperature • Plants have enzymes that work best from 32-95 degrees F. Temperatures above or below can damage these enzymes which can slow down or stop photosynthesis.

  29. Factors Affecting Photosynthesis • Intensity of light • Increasing light intensity increases the rate of photosynthesis. (It will reach a max level)

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