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Chapter 8 - Photosynthesis Chapter 8 - Photosynthesis

Chapter 8 - Photosynthesis. Overview of Photosynthesis and Respiration Overview of Photosynthesis and Respiration 3. PHOTOSYNTHESIS 5. RESPIRATION 1

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Text of Chapter 8 - Photosynthesis. Overview of Photosynthesis and Respiration Overview of Photosynthesis...

  • Chapter 8 - Photosynthesis


  • Energy Formation in CellsEnergy for LifeATPADP and POrganic Compounds & OxygenCarbon Dioxide & Water

  • Overview of Energy FormationPlants use sunlight to make food (Carbohydrates, sugars, etc) This is stored energy thoughThen cellular respiration occurs in the mitochondria which takes the food and breaks it down into usable energy, or ATP

  • What is ATP?Adenosine triphosphate- a chemical compound that can store and release energy

  • How does ATP work?The energy in ATP lies in the bond between the 2nd and 3rd phosphateIf you break the bond and release the phosphate energy is released which leaves you with ADPIf you add a phosphate to ADP you store energyEnergy

  • Where does it occur?In plants that are able to capture sunlight to make their own food (aka autotrophs.)The actual process occurs inside a cells chloroplasts.

  • What does it need?


    WATER (H20)


  • What happens? (photosynthesis equation)6CO2 +6H2O +ENERGYC6H12O6 +6O2 Carbon DioxideWaterCarbohydratesOxygenSunlight

  • How does happen?The process of photosynthesis does not happen all at once. It is a very long process that is broken into 3 stages.

  • Stage 1 Light ReactionsLight is absorbed from the sun by the chloroplasts.

    H2O is taken into the cell as well.

    The light energy is used to split H20 into 3 separate parts (H, O2, and electrons.)

  • How does it work?Inside the chloroplasts are disk-shaped structures called thylakoids that contain different pigments.

  • How does it work?Pigments do the actual absorbing of light.

    a) Chlorophylls absorb red and blue light (produce green colors)

    b) Carotenoids absorb other colors(produce yellow and orange colors)

  • How does it work?Once the sunlight is captured it is used to split water (H20) into Hydrogen (H), Oxygen gas (O2), and free electrons.

    Oxygen gas (O2) is free to leave the plant and this is what animals use to breathe.

  • Stage 2 Energy StorageFree electrons are passed from thylakoid to thylakoid until they reach an ADP molecule and turn it into an ATP.

    Hydrogen (H) molecules are passed from protein to protein until they reach a NADP+ molecule and then they become an NADPH.

  • How does it work?As electrons continuously get passed on this process is known as the electron transport chain.

  • Stage 3 Dark ReactionsThe newly formed ATP and NADPH power the formation of carbohydrates, sugars, and starches.

    This is done by using CO2 as the starting material.

  • How does it work?Carbon Dioxide (CO2) enters the cell from the atmosphere and undergoes a process called the Calvin Cycle which creates simple sugars.

  • Step 1A Carbon Dioxide molecule is joined to a 5-carbon compound called RuBP (ribulose bisphosphate) to create a 6-carbon compound.

  • Step 2The newly formed 6-carbon compound immediately splits into two 3-carbon compounds.

  • Step 3One of the new 3-carbon compounds is used to make the initial 5-carbon compound that originally joined to the Carbon Dioxide.

  • Step 4The second 3-carbon compound is used to make carbohydrates, sugars, and starches.

  • Summary of Stages

  • Factors that affect it?Light intensityAmount of CO2 availableTemperature

    If any of these factors increase the photosynthesis process also increases and vice versa.

  • PhotosynthesisH2OCO2O2C6H12O6Light ReactionDark ReactionLight is AdsorbedBy ChlorophyllWhich splitswaterChloroplastATP andNADPH2ADPNADPCalvin CycleEnergyUsed Energy and is recycled.++

  • PhotosynthesisCapturing Energy from the Sun*Using energy to make ATP and NADPH*Using ATP and NADPH to make carbohydrates, sugars, and starches ** Light Dependent Reactions* Light Independent Reactions (Calvin Cycle)

  • Any Questions?

    Education is light, lack of it darkness.--Russian Proverb

    Education is the movement from darkness to light.--Bloom