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Published byCecil Goodman Modified over 9 years ago
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Cell Energy: Photosynthesis
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Where Does Energy Come From? Autotrophs: Use light energy from the sun to produce food necessary to give them energy. Heterotrophs: Can’t use the energy of the sun, these organisms need to obtain energy from foods they consume.
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Energy Energy comes in many forms: Light, Heat, Electricity. One source of chemical energy that living things use is adenosine triphosphate (ATP).
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ATP: Adenosine Triphosphate Consists of: Adenosine A 5-Carbon sugar called Ribose 3 Phosphate groups (the key to its ability to store and release energy). Energy storage and release Cells have the ability to store energy in small amounts (3-5 seconds) ADP (energy source like ATP but with one less phosphate group) must add a phosphate group so the cell can store energy, Energy will be released from that ATP when that same phosphate group is removed. ATP powers many reactions this way (active transport, protein synthesis, muscle contraction)
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Photosynthesis The process which plants use to convert the energy of sunlight into carbohydrates (sugars and starches) they can use as an energy source.
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Scientist of Photosynthesis Van Helmont- Experimented to see if plants grew by taking materials out of soil. He concluded that water was responsible for the majority of plant growth. He had it ½ right, he didn’t realized that the carbon dioxide in the air was used with the water and sunlight to produce energy.
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Scientist of Photosynthesis Priestly- Experimenting with a fig plant and a candle under a jar, discovers that plants release a chemical (we now know is Oxygen) that allows the candle to burn. Ingenhousz-Discovers that plants produce oxygen when in light but, not in the dark.
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Photosynthesis The photosynthesis reaction: 6CO 2 +H 2 O --> C 6 H 12 O 6 +6O 2 (With light present). The photosynthesis reaction requires: Light, Water, and Carbon Dioxide. The light used for photosynthesis to occur, is captured by a green pigment (chlorophyll) stored in the chloroplast. Plants also contain other pigments (red, orange, yellow, etc.) that absorb light from another part of the spectrum that chlorophyll does not absorb.
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Photosynthesis Inside the Chloroplast: Chloroplast Envelope- Made of an inside and outside membrane surrounds the chloroplast. Thylakoids- Saclike photosynthetic membrane (location of Light Reaction). Granum- Stack of thylakoids Photosystems- Proteins in the thylakoids organize chlorophyll and other pigments into clusters known as photosystems, this is the light collecting unit of the chloroplast. Stroma- Space outside of the thylakoids (location of Dark Reaction).
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Photosynthesis Light Reaction: The first step of photosynthesis. Requires Light. Takes place in the Thylakoids. Uses sunlight to produce Oxygen and convert ADP & NADP into ATP and NADPH. Requires water (H 2 O).
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Photosynthesis The steps of a Light Reaction 1.Pigments begin to absorb light, which is used to break up water molecules into H + and O (which is released into the air). 2.Energy from electrons in the electron transport chain is used to transport H + from the stroma into the thylakoid. 3.Energy from light is used to reenergize electron. NADP picks up these electron along with H + at the outer surface of the thylakoid to become NADPH. 4.As electrons pass from chlorophyll to NADP, more H + ions are passed across the membrane, after a while the inside becomes (+) and the outside becomes (-) this difference in charge provides the energy necessary to make ATP. 5.H + use a protein called ATP synthase to help it pass through the membrane, as H + passes the membrane it rotates the protein, As it is rotating it binds ADP and a phosphate group together producing ATP.
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Photosynthesis Dark Reaction: Also known as the Calvin Cycle, it is the second step in photosynthesis. Takes place in the Stroma. Uses the energy from the ATP and NADPH produced by the light reaction to make high energy sugars. Doesn’t require light. Requires CO 2.
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Photosynthesis The steps of a Dark Reaction: 1.6 carbon dioxide molecules enter the reaction in the stroma, they combine with 6 (5 carbon) molecules to make 12 (3 carbon) molecules. 2.Energy from ATP and high-energy electrons from NADPH are used to convert the 12 (3 carbon ) molecules into high-energy forms. 3.2 of the 12 (3 carbon ) molecules are removed from the cycle, the plant cell uses these molecules to produce; sugars, lipids, amino acids, and other molecules needed for plant metabolism and growth. 4.The remaining 10 (3 carbon) molecules are converted back to 6 (5 carbon) molecules like the cycle started with, they will be used to start the cycle over again.
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Photosynthesis
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