4.2 Overview of Photosynthesis Updates: Unit 4 quiz 1 Unit guide 4.2/4.3 # 1 – 5 due Last call for unit 3 work! Homework: –Read 13.4 –HW: Unit guide 13.4 # 1 - 4

4.2 Overview of Photosynthesis LEQ: How does photosynthesis transform abiotic factors into living matter and energy? Activator: ATP cycle review –Return to your groups and answer the ATP cycle questions Key terms –photosynthesis, primary production chlorophyll, light-dependent reactions, Calvin cycle (light- independent reactions)

4.2 Overview of Photosynthesis Which of the following molecules in the ATP cycle is used by cells to power cell processes? A) lipids B) ADP C) ATP D) carbohydrates Where does the energy to power the ATP cycle come from? A) exothermic rxns B) endothermic rxns C) heat D) all Which nutrient is most commonly used to generate ATP? A) nucleic acids B) carbs C) lipids D) proteins

4.2 Overview of Photosynthesis Photosynthetic organisms transform matter and energy. Photosynthesis transforms sunlight and Earth’s chemistry into carbohydrates, lipids, etc. –The production of these molecules is called primary production. –Molecules that are not used for energy becomes the visible body parts of plants (net primary production)

4.2 Overview of Photosynthesis sugars water and mineral nutrients Plants must manage water efficiently, compete for light Vascular tissue disperses sugars from the leaves –allows plants to grow higher off the ground Plants have specialized structures for photosynthesis

4.2 Overview of Photosynthesis Waxy cuticles and stomata minimize water loss evaporation. stom a

4.2 Overview of Photosynthesis Chlorophyll is a molecule that absorbs light energy. –found in chloroplasts of eukaryotes. Photosynthesis requires abiotic factors to produce food. chloroplast leaf cell leaf

4.2 Overview of Photosynthesis The equation for the overall process is: 6CO 2 + 6H 2 O + ATP  C 6 H 12 O 6 + 6O 2 C 6 H 12 O 6 granum (stack of thylakoids) thylakoid sunlight 1 six-carbon sugar 6H 2 O 6CO 2 6O 2 chloroplast energy stroma (fluid outside the thylakoids)

4.2 Overview of Photosynthesis Transformation: the light-dependent reactions in thylakoids: 1) H 2 O supplies electrons, sunlight powers water-splitting 2) oxygen is produced as waste Payoff: ATP made for chloroplast; electrons stored for bonds

4.2 Overview of Photosynthesis A Closer Look: Electron Transport and H + Gradients

4.2 Overview of Photosynthesis The light-independent reactions (Calvin cycle) in the stroma. 3) CO 2 supplies carbon for sugar formation: 4) ATP supplies energy; electrons for bonds = sugars Payoff: carbohydrates for food, growth, reproduction, etc.

4.2 Overview of Photosynthesis Which pigment absorbs sunlight to begin the transformation? A) Chlorophyll B) chloroplasts C) water D) oxygen Which chemical is used for an electron supply? A) water B) sugars C) oxygen D) carbon dioxide Which process requires ATP? A) light absorption B) Calvin cycle C) both D) none Which process actually produces sugars? A) light dependent B) light independent

4.2 Overview of Photosynthesis Discussion & Review: Review the process of photosynthesis described so far: –Role of water –Role of chlorophyll/thylakoid membranes –Production of oxygen –Electron transport –ATP synthase –NADP/NADPH

4.2 Overview of Photosynthesis Review Which chemical reactant is required to produce glucose? What is the process that produces glucose called? Where does the energy required to power this endothermic reaction come from? Are plants water-dependent, light-dependent or both? Explain. Why are plants sometimes a little short on ATP and carbon dioxide? –How might these “limits of tolerance” in turn limit the distribution of plant species?

4.2 Overview of Photosynthesis discovering photosynthesis Why did von Helmont think that plants got their nourishment from soil? What do you think von Helmont concluded when he measured the change in weight of the plant and the soil? Do you think that the factory is a good analogy for the process of photosynthesis in plants?

4.2 Overview of Photosynthesis Summary: Explain why photosynthesis is important for maintaining homeostasis in plant cells. –What does the cell require to carry out this process? –Why is oxygen released? –How is carbon dioxide converted into simple carbohydrates? Explain how an electron transport chain operates.