Lecture 15Outline of Last Lecture1) Define chemiosmosis, and explain how a gradient of protons is established across the inner mitochondrial membrane.2) Describe the process by which the proton gradient drives ATP synthesis inchemiosmosis.3) Summarize how the products of protein and lipid catabolism enter the same metabolic pathway that oxidizes glucose.4) Compare and contrast anaerobic respiration and fermentation; include themechanism of ATP formation, the final electron acceptor, and the end products.Outline of Current Lecture1) Diagram the structure of a chloroplast.2) Describe what happens to an electron in a biological molecule when a photon of light energy is absorbed, using the reaction center chlorophyll as an example.3) Explain the concept of photolysis and how it relates to the oxygen in the atmosphere.4) Distinguish between the light reactions and CO2 reactions of photosynthesis in terms of their LOCATION in the chloroplast, their STARTING MATERIALS, and END PRODUCTS 5) Describe the flow of electrons through photosystems I and II in the noncyclic electron transport pathway (photophosphorylation); contrast this with cyclic photophosphorylation.6) Explain how a proton (H+) gradient is established across the thylakoid membrane and how this gradient functions in ATP synthesis.7) Summarize the three phases of the Calvin cycle, and indicate the roles of RUBISCO, ATP and NADPH in the process.8) Discuss how photorespiration reduces photosynthetic efficiency, and compare the C4 and CAM pathways).I. The Chloroplast- A chloroplast is made from several components, as seen here:These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. BIOL 101 1st Edition- Granum are stacked membrane structures that hold the chloroplast and chlorophyll of a plant cell, and this is where the light reaction occurs in photosynthesis.- Thykaloids are membrane bound compartments inside of chloroplasts where the light dependent reactions of photosynthesis occur. The space within a thykaloid is called a lumen.- The Stroma is the cytoplasm area of a chloroplast, and this iswhere the calvin cycle takes place.II. Photons in a Light Reaction- When photons hit a plant cell, the photon goes to the chlorophyll molecule. This excites the molecule’s electrons, putting the electrons in a high energy state. This high state of energy pumps H+ ions in the stroma into the lumen, just like H+ ions going from the cytosol to the mitochondrial matrix, except this is in plant cells.III. Photolysis- This process is when the energy from a photon breaks a molecular bond, IE when a photon breaks H2O into O and 2H. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. BIOL 101 1st EditionPlants breaking down CO2 accounts for the abundance of oxygen in the atmosphere that we breathe.IV. Light Reactions v.s. CO2 Reactions- Light Reactions: Light reactions occur within the thykaloids. Photons break H2O into O and 2H. These are turned into ATP and NADPH.- CO2 Reactions: The CO2 reactions occur as the Krebs cycle, basically CO2 goes in, goes around twice in the cycle, and Glucose (C6-H12-O6) is produced. This occurs in the stroma.V. Noncyclic Electron Transport- Photons go into Photosystem II, breaks H2O into O+2H, and excites the chlorophyll electrons, which go up into an electron acceptor molecule. This energy is released to form ATP, and the electrons go down an electron transport chain into Photosystem I, where the same process as the last occurs (minus the H2O breaking), and the electrons sent up into a secondary electron acceptor molecule are tagged at the end of an NADP+ to form an NADPH.- Cyclic Photophosphoryllation involved only one photosystem. Light hits the electrons and excites them. The electrons go up through the excited reaction center, lose energy (that is used for the production of ATP), and go back into the initial reaction center.VI. Proton Gradient- A proton gradient is established much like how one is established in a mitochondria. The high energy given to the electrons by the photons sends the electrons outside of the chlorophyll. Many H+ protons are outside the chlorophyll now,and this is where the concentration gradient comes from, These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. BIOL 101 1st Editionwhich pushes the protons back through the membrane from where they came.VII. The Calvin Cycle- The Calvin Cycle is split into 3 parts, carbon fixation, reduction, and RuBP regeneration. Basically, CO2 goes in, is turned into G3P through the reduction process and Rubisco, is accepted by RuBP and turned into half of glucose, RuBP is regenerated and the cycle goes around again, creating a full glucose.VIII. Photorespiration, C4 & CAM- In carbon fixation, Rubisco wants to add 2 carbons onto the CO2 that comes into the calvin cycle. However, in photorespiration, ocygen is added on instead, making it unable to be used in the calvin cycle, thus reducing efficiency.- C3 photosynthesis is called this due to the carbon fixation within the calvin cycle, the CO2 is turned into a 3 carbon compound. The CAM photosynthesis is when a plant’s stoma close during the day to hold in water, and open at night and perform photosynthesis then. At night, CO2 is converted to anacid and stored. During the day, this is broken down and the CO2 is released to rubisco for photosynthesis.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. BIOL 101 1st