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REPORT ABOUT PHOTOSYNTHESIS.pptx

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REPORT ABOUT PHOTOSYNTHESIS.pptx

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Its all about the process in photosynthesis what plants will get after getting the light there some broad process that can be explain to this PowerPoint presentation feel free to read hehe huhu haha nsisksm xhjxksks hsusksksi. hsjsksks hsusjsnjs hsismsnhx hsisnsjuxh ftuis yusnshdydu gyssbshid gyzbsbsh hsusjshhs jusjsjs hsjsjshjs judbdbd

Its all about the process in photosynthesis what plants will get after getting the light there some broad process that can be explain to this PowerPoint presentation feel free to read hehe huhu haha nsisksm xhjxksks hsusksksi. hsjsksks hsusjsnjs hsismsnhx hsisnsjuxh ftuis yusnshdydu gyssbshid gyzbsbsh hsusjshhs jusjsjs hsjsjshjs judbdbd

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REPORT ABOUT PHOTOSYNTHESIS.pptx

  1. 1. PHOTOSYNTHESIS
  2. 2. What is Photosynthesis? Is a process by which plants used sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar. C P Most life on Earth depends on photosynthesis C P
  3. 3. Photosynthesis is an endothermic process that involves the oxidation-reduction (redox) reactions, as summarized in the formula shown below; 02 03
  4. 4. THREE PRINCIPAL CHEMICAL ELEMENTS OXYGEN HYDROGEN CARBON DIOXIDE ~ make sugar molecules and oxygen. ~make plants more productive. O2 H CO2 ~ Proton gradients and Plant Respiration. ~Glucose. ~Byproduct
  5. 5. MORE IMPORTANT ELEMENTS ~to absorb light. SUN ~provides necessary light and energy to plants. WATER ~provides a hydrogen CHLOROPHYLL GASES ~carbon dioxide (CO2) ~ help plants grow
  6. 6. The two process of photosynthesis occurs in two distinct stages; LIGHT-DEPENDENT REACTIONS LIGHT-INDEPENDENT REACTIONS - Do not required sunlight - Required sunlight - Convert light energy into chemical energy.
  7. 7. PROPERTIES OF LIGHT - Light is a form of electromagnetic radiation. - Light particles called photon acts like a discrete bundle of energy called quantum. - Energy content of a quantum is inversely proportional to the wavelength of the light. (figure 1) - Only visible light is ideal for biological reactions. - Light beyond 700 nm has insufficient quantum yield to drive photosynthesis (figure 2)
  8. 8. PHOTOSYNTHETIC PIGMETS - Pigment that is present in chloroplast or photosynthetic bacteria and captures the light energy necessary for photosynthesis. - Pigments are light –harvesting molecules. - In plants, they are present in the thylakoid membranes of chloroplast. 5 MAIN TYPES OF CHLOROPHYLLS - Chlorophyll a - Chlorophyll b - Chlorophyll c - Chlorophyll d - Bacteriochlorophyll a (molecules found in prokaryotes) - Chlorophylls absorb photons with narrow energy range. (figure 4) - Carotenoids and Xanthophylls serve as antenna pigments, extending the range of light useful for photosynthesis. (figure 5)
  9. 9. LIGHT-DEPENDENT REACTION - Convert solar energy into chemical energy in the form of NADPH and ATP. - Photons are absorbed by the photosynthetic pigments organized into photocenters in the chloroplast membrane (figure 6). - Each photocenter contains a hundreds of pigment molecules that act as antennae to absorb light and transfer the energy of their excited electrons to a chlorophyll molecule that serves as a reaction center (figure 7).
  10. 10. Two electron transport pathways used to make ATP molecules NON-CYCLIC PHOTOPHOSPHORYLATION - Happens when an electron passes through PSII to PSI and drives the synthesis of ATP and NADPH (figure 8) CYCLIC PHOTOPHOSPHORYLATION - Light energy harvested at PSI is used to synthesizing ATP rather than NADPH, thereby supplying additional ATP for other metabolic processes. ( figure 9)
  11. 11. NON-CYCLIC PHOTOPHOSPHORYLATION Steps in the non-cyclic photophosphorylation pathway of light-dependent reactions; 1. Once the energy from the absorbed photon reaches the PS II special pair (P680), the special pair can lose an electron when excited, passing it to the primary electron acceptor, pheophytin, an organic molecule that resembles chlorophyll. 2. The electron will begin its journey through an electron transport chain. Pheophytin transfers the electron first to plastoquinone (pq). Pq transfers the electron to a cytochrome complex (Cyt), then a cooper-containing protein, plastocyanin (Pc), accepts the electron. As this high-energy electron moves through this electron transport chain, it losses or releases energy. It goes from its high to lower energy state. Some of the released energy is used to pump protons (H+) from the stroma (outside of the thylakoid) into the thylakoid interior.
  12. 12. NON-CYCLIC PHOTOPHOSPHORYLATION Steps in the non-cyclic photophosphorylation pathway of light-dependent reactions; 3. After the special pair gives up its electron, it has a positive charge and needs a new electron. This electron is replaced by extracting a low-energy electron from the splitting of water molecules (photolysis) carried out by a portion of PSII called the manganese center. The splitting of one H2O molecules releases two electrons, 2 H+, and one atom of oxygen. Two molecules of H2O are needed to form one O2 molecule. Mitochondria in the leaf use about 10% of the oxygen to support oxidative phosphorylation, while the remainder escape to the atmosphere. Aerobic organisms use this oxygen in the atmosphere for respiration. This transfer of H+, along with the release of H+ from photolysis/Hill reaction by the manganese center of chlorophyll, forms a proton gradient. The ATP synthase uses the energy from the proton gradient to add inorganic phosphate (Pi) to ADP to make ATP. This process of making ATP using energy stored in a chemical gradient is called chemiosmosis.
  13. 13. NON-CYCLIC PHOTOPHOSPHORYLATION Steps in the non-cyclic photophosphorylation pathway of light-dependent reactions; 4. Once an electron has gone down the first electron transport chain and arrives at PSI, it joins with the chlorophyll a special pair called P700. because the electron has lost energy before its arrival at PSI, it must be re-energized through absorption of another photon by PSI antenna pigments. 5. P700 (PS I) is oxidized and sends the high-energy electron to its primary electron acceptor, chlorophyll A0, and down to a short electron transport chain. 6. The electron is first passed to a protein called ferredoxin (Fd), the transferred to an enzyme called NADP+ reductase. 7. NADP+ reductase transfers electrons to the electron carrier NADP+ to make NADPH. NADPH will travel to the Calvin cycle, where the synthesis of sugars from carbon dioxide utilizes its electrons. Thus, PSII captures the energy to create proton gradients to make ATP, and PSI captures the same to reduce NADP+ into NADPH. The two photosystems work in concert to guarantee the equal production of NADPH and ATP. Other mechanisms (cyclic photophosphorylation) exist to fine-tune that ratio to exactly match the chloroplast’s constantly changing energy needs.
  14. 14. CYCLIC PHOTOPHOSPHORYLATION Cyclic photophosphorylation of light- dependent reactions has the following steps: 1. The antenna complex captures two photons from either the red or blue spectrum and donates them to the P700 reaction center, which contributes two high-energy electrons to the primary electron receptor. 2. High-energy electrons are passed to ferredoxin (fd), an iron containing protein which acts as the first electron carrier. 3. A second electron carrier plastoquinone (Pq), carries the electrons to a complex of two cytochromes. In the process, energy is provided to produce a proton gradient across the membrane, facilitating chemiosmosis that forms additional ATP molecules. 4. The electrons are returned by plastocyanin (Pc) to the 700 pigment in the reaction center to complete the cycle.
  15. 15. LIGHT-INDEPENDENT REACTION - Do not required sunlight. - Cell has the fuel needed to make carbohydrate molecules for long-term energy storage. - The ATP and NADPH molecules have lifespans in the range of millionths of seconds whereas, products of the light-independent reactions (carbohydrates and other forms of reduced carbon) can survive for hundreds of millions of years. - The carbohydrate molecules made have a backbone of carbon atoms that come from carbon dioxide, the gas that is a by-product of respiration in microbes, fungi, plants, and animals. - In plants, CO2 enters the leaves through stomata, where it diffuses through intercellular spaces until it reaches the mesophyll cells and into the stoma of the chloroplast, the site of light-independent reactions. - The reaction as a whole are also called the Calvin cycle, named after Melvin Calvin. - Most outdated name is dark reactions
  16. 16. Relation of light-dependent and light-independent reactions
  17. 17. The light-independent reactions or Calvin cycle consist of three main stages: fixation, reduction, and regeneration. STAGE 1: Fixation - In addition to CO2, an enzyme called ribulose bisphosphate carboxylase (RuBisCO) and six ribulose bisphosphate (RuBP) initiate the light-independent reactions in the stroma ( figure 10). - RuBisCO catalyzes a reaction between CO2 and ruBP. For each CO2 molecule that reacts with one RuBP, two molecules of another compound (3-PGA) form. PGA has three carbons and one phosphate. Each turn of the cycle involves only one RuBP and one carbon dioxide and forms two molecules of 3-PGA. The number of carbon atoms remains the same, as they move to form new bonds during the reactions (3 atoms from 3CO2 + 15 atoms from 3RuBP is 18 atoms of carbon in 3 atoms of 3-PGA). This process is called carbon fixation because inorganic CO2 is ‘fixed’ into organic molecules.
  18. 18. The light-independent reactions or Calvin cycle consist of three main stages: fixation, reduction, and regeneration. STAGE 2: Reduction Six ATP and NADPH molecules are used to convert the six molecules of 3-PGA into six molecules of glyceraldehyde 3-phosphate (G3P). That is a reduction reaction because it involves the gain of electrons 3-PGA. Recall that a reduction means the gain of an electron by an atom or molecule. Six molecules of both ATP and NADPH are used. For ATP, energy is released with the loss of the terminal phosphate atom, converting it into ADP. For NADPH to become NADP+, both energy and a hydrogen atom are lost. Both ADP and NADP+ return to the nearby light-dependent reactions to be reused and reenergized. (figure 10)
  19. 19. The light-independent reactions or Calvin cycle consist of three main stages: fixation, reduction, and regeneration. STAGE 3: Regeneration At this point, only one of the G3P molecules leaves the Calvin cycle and is sent to the cytoplasm to contribute to the formation of other compounds needed by the plant. Because each G3P exported from the chloroplast has three carbon atoms, it takes three ‘turns’ of the Calvin cycle to fix enough net carbon to export one G3P. But each turn makes two G3Ps thus, three turns make six G3Ps. Out of six, one is exported while the remaining five G3P molecules remain in the cycle and are used to regenerate RuBP, which allows the system to prepare for more CO2 fixation. The regeneration reactions involving five G3P use three molecules of ATP. (figure 10)
  20. 20. The figure above summarizes the processes of the two reactions of photosynthesis. Photosynthesis transformed life on earth. By harnessing energy from the sun, photosynthesis evolved to allow living things access to enormous amounts of energy. Because of photosynthesis, living things gained access to sufficient energy sources that allowed them to build new structures and achieve the evident biodiversity today.
  21. 21. GROUP 2 MEMBERS; ~ Abecia, Tejoice ~ Lumakin, Dan C. ~ Lopez, Neil Jean ~ Mellejor, Ma. Kaye Jenissa V. ~ Templanza, Aldrin M. II
  22. 22. FIGURE 1: ELECTROMAGNETIC SPECTRUM
  23. 23. FIGURE 2: RELATION OF WAVELENGHT OF LIGHT,QUANTUM YIELD AND PHOTOSYNTHESIS
  24. 24. List of photosynthetic pigments (in order of increasing polarity): - CAROTENE: an orange pigment - XANTHOPHYLL: a yellow pigment - PHAEOPHYTIN A: a gray- brown pigment - PHAEOPHYTIN B: a yellow-brown pigment -CHLOROPHYLL A: a blue-green pigment - CHLOROPHYLL B: a yellow-green pigment
  25. 25. Figure 4: Visible light absorbed by chlorophyll
  26. 26. Figure 5: Wavelength of light absorb by photosynthesis
  27. 27. Figure 6: Each photocenter consists of hundreds of antenna pigment molecules, which absorb photons and transfer energy to a reaction center chlorophyll. The reaction center chlorophyll then transfers its excited electrons to an acceptor (pheophytin) in the electron transport chain.
  28. 28. Figure 7: Each photosystem has light-harvesting complex consist of antenna pigments, chlorophyll b and carotenoids, that pass the light energy absorbed through resonance energy transfer until it reaches chlorophyll a, the reaction center.
  29. 29. Figure 8
  30. 30. Figure 9
  31. 31. Figure 10
  32. 32. Figure 10
  33. 33. Figure 10

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