Photosynthesis Answer Key

Photosynthesis Animations Student Worksheet INTRODUCTION This worksheet complements the animation series Photosynthesis. PROCEDURE 1. This animation series contains seven parts. Read the questions below for each part before watching it. 2. After watching each part, answer the questions in the spaces provided. 3. After completing all seven parts of the animation, answer the summary questions in Part 8. QUESTIONS PART 1: OVERVIEW 1. Which of the following kinds of organisms do photosynthesis? Select all that apply. _ ✔_plants _ _fungi _ _animals _✔_algae _ _all bacteria _✔_some bacteria 2. What is the overall purpose of photosynthesis? Photosynthesis nourishes almost the entire living world. Its purpose is to capture light energy from the sun and convert it into chemical energy. 3. On Diagram 1, fill in the labels with photosynthesis’s main inputs and outputs of matter and energy. Oxygen Carbohydrat es Sun Water PART 2: CHEMICAL PROCESS 1. Complete the following sentence. chemical reactions C02 light Photosynthesis is a set of ____________________________ in which ____________energy is converted to chemical __________________energy. Page 1 Photosynthesis of 7 Animat Animations ions Stud Student ent Works orksheet heet Photosynthesis 2. On Diagram 2, fill in the labels with the following descriptions. Some of the objects have multiple labels. • • • • • • • • water (H2 O) carbon dioxide (CO2) oxygen (O2) G3P (sugar) electron acceptor electron donor carbohydrates energy input lightenergy Water C02 Carbohydrates Oxygen G3P Electron acceptor Electron Donor PART 3: LEAF STRUCTURE 1. In what plant structures does photosynthesis occur? Make your description as specific as you can. 2. On Diagram 3, complete the following tasks. a) Draw how CO 2 gets into the leaf. b) Draw how O2 gets out of the leaf. c) Label the name of the structure through which these gases pass. O2 Stomata C02 3. What structure is used to transport organic molecules from the leaf to other parts of the plant? The plumbing system found in the Vascular bundles is used to transport organic molecules from the leaf to other parts of the plant. 4. Why are leaves green? Leaves are green because they have cells containing chlorophy ll. Page 2 Photosynthesis of 7 Animat Animations ions Stud Student ent Works orksheet heet Photosynthesis PART 4: CHLOROPLASTS 1. On Diagram 4, label the following items. Multiple labels may apply to the same part of the diagram. • • • • location of the light reactions location of the Calvin cycle thylakoid stroma Calvin Cycle Stroma Light Reactions Thylakoids 2. On Diagram 5, fill in the labels with the following descriptions to show the connections between the light reactions and the Calvin cycle. • • • • • carbon dioxide (CO 2) oxygen (O2) G3P (sugar) ATP NADPH C02 ATP NADPH 02 G3P 3. How does a plant increase its biomass? A plant increases its biomass through the formation of creating organic molecules. PART 5: LIGHT REACTIONS Photosystems I and II (PSI and PSII) 1. What is the function of the photosystems? They transform light energy to chemical energy by exiting electrons and then moving them from molecule to molecule. 2. On Diagram 6, complete the following tasks. Page 3 Photosynthesis of 7 Animat Animations ions Stud Student ent Works orksheet heet Photosynthesis a) Label PSI and PSII. b) Draw the path of the electron transport chain. The Events of the Light Reactions 3. For PSII, the cytochrome complex, and PSI, draw and label what happens at that structure on Diagram 6. Then describe the events in a bulleted list in Table 1. Table 1: Descriptions of the steps in the light reactions. Structure What is happening with matter? PSII Exciting and then shuttling electrons fro molecule to molecule, Electrons replace the electrons lost cytochrome complex PSI What is happening with energy? Because of the water splitting reaction, light energy can be converted into chemical energy. The cytochrome complex is an enzyme composed of two protein complexes that transfers electrons The electrons in the chlorophyll use a high energy level and get used to send chlorophyl A second electron is received and passed These electrons now have lost most of their energy they gained from During the light-dependent reactions, an electron that's excited in PS2 is passed down to PS1 4. At the end of the electron transport chain, where is the light energy that was absorbed and converted by chlorophyll stored? List two answers. Energy absorbed by sunlight is stored by two types of energy- carrier molecules: ATP AND NADPH. The energy that these molecules carry is stored in a bond that holds a sign atom to the molecule. Page 4 Photosynthesis of 7 Animat Animations ions Stud Student ent Works orksheet heet Photosynthesis Chemiosmosis and ATP Synthase 5. Label the ATP synthase on Diagram 6. 6. Describe how the proton (H+) gradient is used to make ATP. Protons flow down with their concentration gradient into the matrix through the membrane protein ATP synthase. 7. What two molecules bring chemical energy from the light reactions to the next stage of photosynthesis, the Calvin cycle? ATP AND NADPH PART 6: CALVIN CYCLE 1. Label Diagram 7 with the three phases of the Calvin cycle. x3 c02 3x RuBP x6 3-pga x6 G3P 5x G3p 3 ADP + 3 Pi 3 ATP 6 ATP 6 NADPH 6 ADP+Pi Briefly describe what is going on in each phase and answer the questions shown. Phase 1 (Diagram 8) Description: Three molecules of carbon dioxide react with 3 molecules of ribulose bisphosphate to produce 6 molecules of a 3 carbon molecule What enzyme catalyzes the reaction in this phase? Rubisco Page 5 Photosynthesis of 7 Photosynthesis Animat Animations ions Stud Student ent Works orksheet heet Phase 2 (Diagram 9) Description: The 6 molecules of 3 PGA use 6 molecules of ATP and six molecules on NADPH - which store energy from light reactions to generate 6 molecules of G3P Phase 3 (Diagram 10) Description: In the process electrons lost from NADPH are accepted by the carbons from carbon dioxide molecules. Why is the series of reactions in the Calvin cycle called a “cycle”? The energy lost from ADP are accepted by carbon dioxide molecules 2. At the end of the Calvin cycle, what molecules have the energy that originally came from light? G3P and carbon molecules PART 7: BIOSYNTHESIS 1. Complete the following sentence based on Diagram 11. Glyceraldehyde-3-phosphate (G3P) can be used by plant cells to make starch Sucrose ___________________ and _________________. 2. Which molecule in Diagram 11 is used to transport energy to other parts of the plant? G3P 3. Which molecule in Diagram 11 is stored in the plant for later use as an energy source? starch Page 6 Photosynthesis of 7 Photosynthesis Animat Animations ions Stud Student ent Works orksheet heet PART 8: TEST YOUR KNOWLEDGE 1. Based on everything you’ve learned from the animations, what is the overall purpose of photosynthesis? The purpose is to convert light energy into chemical energy. 2. Describe how oxygen gas (O2) is produced during photosynthesis. Include the specific structures in the plant where the reaction occurs. C02 enters through the stomata and water is absorbed, the Co2 and water react with each other in the sunlight and it produces O2 and glucose. 3. Describe the path of an electron from a molecule of water to the sugar G3P. H+ to ATP, then it joins the sugar G3P 4. Describe how ATP is produced in the light reactions. Energy generated by the hydrogen ion stream allows ATP to attach a third phosphate to ATP. 5. Which of the following statements best explains how the energy in a photon of light is stored in a molecule of C the sugar G3P? ________ a. Light energy directly provides energy to RuBP and CO2, which produce G3P in the Calvin cycle. b. Light energy directly provides energy to ATP synthase, which produces ATP during the light reactions. c. Light energy energizes electrons to make ATP and NADPH, which provide energy to produce G3P in the Calvin cycle. 6. When three molecules of carbon dioxide (CO2) react with three molecules of RuBP during the Calvin cycle, six molecules of the sugar G3P are produced. One G3P molecule exits the Calvin cycle during Phase 2. What happens to the other five G3P molecules? One G3P molecule leaves the cycle and will go towards making glucose, while five G3P molecules must be recycled to regenerate the RuBP acceptor. Page 7 Photosynthesis of 7