General Biology 1 Module 9 PDF - Patterns of Electrons Flow Through Light Reactions - 2021

Senior High School GENERAL BIOLOGY 1 Module 9: Patterns of Electrons Flow Through Light Reaction Events AIRs - LM LU_General Biology 1_Module9  GENERAL BIOLOGY 1 Module 9: Patterns of...

Senior High School GENERAL BIOLOGY 1 Module 9: Patterns of Electrons Flow Through Light Reaction Events AIRs - LM LU_General Biology 1_Module9  GENERAL BIOLOGY 1 Module 9: Patterns of Electrons Flow through Light Reaction Events Second Edition, 2021 Copyright © 2021 La Union Schools Division Region I All rights reserved. No part of this module may be reproduced in any form without written permission from the copyright owners. Development Team of the Module Author: Rochelle O. Mendoza Editor: SDO La Union, Learning Resource Quality Assurance Team Content Reviewer: Maria Lourdez Ortiz Language Reviewer: Reynaliza Borja Illustrator: Ernesto F. Ramos, Jr. Design and Layout: Dexter B. Soller Management Team: Atty. Donato D. Balderas, Jr. Schools Division Superintendent Vivian Luz S. Pagatpatan, Ph.D Assistant Schools Division Superintendent German E. Flora, Ph.D, CID Chief Virgilio C. Boado, Ph.D, EPS in Charge of LRMS Rominel S. Sobremonte , Ph.D, EPS in Charge of Science Michael Jason D. Morales, PDO II Claire P. Toluyen, Librarian II Printed in the Philippines by: _________________________ Department of Education – SDO La Union Office Address: Flores St. Catbangen, San Fernando City, La Union Telefax: 072 – 205 – 0046 Email Address: [email protected] LU_General Biology 1_Module9  Senior High School GENERAL BIOLOGY Module 9 Patterns of Electrons Flow Through Light Reaction Events LU_General Biology 1_Module9  Introductory Message This Self-Learning Module (SLM) is prepared so that you, our dear learners, can continue your studies and learn while at home. Activities, questions, directions, exercises, and discussions are carefully stated for you to understand each lesson. Each SLM is composed of different parts. Each part shall guide you step-by- step as you discover and understand the lesson prepared for you. Pre-tests are provided to measure your prior knowledge on lessons in each SLM. This will tell you if you need to proceed on completing this module or if you need to ask your facilitator or your teacher’s assistance for better understanding of the lesson. At the end of each module, you need to answer the post-test to self-check your learning. Answer keys are provided for each activity and test. We trust that you will be honest in using these. In addition to the material in the main text, Notes to the Teacher are also provided to our facilitators and parents for strategies and reminders on how they can best help you on your home-based learning. Please use this module with care. Do not put unnecessary marks on any part of this SLM. Use a separate sheet of paper in answering the exercises and tests. And read the instructions carefully before performing each task. If you have any questions in using this SLM or any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator. Thank you. LU_General Biology 1_Module9  Target Humans most constantly take in food and water. Plants must get these substances also into their systems in order to survive. If we trace a food chain, we find green plants as source of food for animals. But how do plants feed? Where do plants obtain energy and the raw materials required for the building of plant matter? If plants create energy for animals to use, they should have a way of replenishing their nutrients. How plants harness energy from and how they converted into carbohydrate molecules is what are we going to study in this lesson. In your previous lesson, you are done with the importance of chlorophyll and other pigments in plants. This module will provide you with information and activities that will help you understand the patterns of electron flow through light reaction. Moreover, this module covers also the second stage of photosynthesis Known as the light- independent reaction or Calvin cycle. After going through this module, you are expected to: 1. Describe the patterns of electron flow through light reaction events. STEM_BIO11/12-IIa-j-4 2. Describe the significant events of the Calvin cycle. STEM_BIO11/12-IIa-j-5 Learning Objectives; 1. identify the important molecules involved and produced in the light reaction and Calvin cycle; 2. describe the events and processes happening during light reactions and Calvin Cycle 3. differentiate the two stages of photosynthesis. Before going on, check how much you know about this topic. Answer the pretest on the next page in a separate sheet of paper. 1 LU_General Biology 1_Module9 PRETEST: Read carefully each item. Write only the letter of the BEST answer for each test item in a separate sheet of paper. 1. Which event occurs first during photosynthesis? A. Carbon dioxide enters through the stomata of the leaves. B. Chlorophyll changes molecules of carbon dioxide and water into glucose. C. Oxygen will be release. D. Plants capture light energy and use that energy to make glucose. 2. What two main products result from photosynthesis? A. Carbon dioxide and water B. Glucose and oxygen C. Glucose and carbon dioxide D. Water and oxygen 3. Which equation describes the chemical reaction of photosynthesis? A. 6 CO2 + 6 H20 C6H12O6 + 6 O2 B. CHO + 02 CO2 + H20 C. CO + HO CHO + O D. CO2 + H20 C6H12O6 + 6 O2 4. Which equation describes the chemical reaction of respiration? A. CO2 + H20 CHO + 02 B. C6H12O6 + 6 O2 6 CO2 + 6 H20 C. CO + HO CHO + O D. C6H12O6 + 6 O2 CO2 + H20 5. Which of the following does not happen during photosynthesis? A. Carbon dioxide enters the leaf through holes called pistil. B. CO2 combines with the stored energy in the chloroplasts through a chemical reaction to make glucose. C. The sugar is moved through tubes in the leaf to the roots, stems and fruits of the plants. D. Some of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue. 6. Which is true about the photosynthetic pigments? A. There is only one kind of chlorophyll. B. Chlorophyll absorbs mostly green light. C. Chlorophyll is required in the Calvin cycle. D. Chlorophyll is formed in the membrane of thylakoids 7. Which of the following describes Photosystem II? \ I. Optimally absorbs photons of wavelength of 700 nm. II. Electron trapped by P 680 are energized by light. III. Responsible in for providing low energy electrons with which to reduce NADP+ to produce NADPH to be used in the Calvin cycle. IV. Electrons are energized by sunlight and passed to a secondary electron acceptor. A. I B. II C. III D. IV 2 LU_General Biology 1_Module9 8. Which describes carbon fixation? A. The conversion process of inorganic carbon to organic compounds by living organisms. B. The conversion process of organic carbon to inorganic compounds by living organisms. C. It forms a 6-carbon compound immediately converted into 2 three- carbon compounds. D. It forms 5-carbon compound immediately converted into 3 two- carbon compounds 9. Which describes the regeneration of RuBP? A. The conversion process of inorganic carbon to organic compounds by living organisms. B. The conversion process of organic carbon to inorganic compounds by living organisms. C. It forms a 6-carbon compound immediately converted into 2 three- carbon compounds. D. It forms 5-carbon compound immediately converted into 3 two- carbon compounds 10. Three turns of Calvin cycle are necessary to produce one net gain of PGAL. Five PGAL molecules are required to regenerate 3 molecules of RuBP. During the three turns how many molecules of ATP and NADPH are use up? A. 3, 6 B. 6, 9 C. 9, 6 D. 6, 3 Lesson Photosynthesis: 1 The Light reaction Jumpstart Photosynthesis is the process by which green plants harness light energy from the sun to convert it to chemical energy of sugar. Let us revisit your previous knowledge on photosynthesis by answering the activity given below. 3 LU_General Biology 1_Module9 Activity 1: Directions: Study the diagram below on photosynthesis before answering the process questions below. 6 CO2 + 6 H2O + sunlight C6H12O6 + 6 O2 Q1. What are the reactants involved in the process? Q2. What are the products of photosynthesis? Discover The equation above is simple but the exact mechanism by which photosynthesis occurs is complicated. For convenience, the process may be divided into two phases: 1. the light-dependent phase or photochemical reaction that occurs in the granum and requires the presence of light energy; and 2. the-independent phase/Calvin Cycle or carbon fixation that occurs in the stroma with or without light. The products of the light-dependent phase are used as reactants in the light-independent phase. Hence, the light-dependent phase is a prerequisite to the light-independent phase. Carbon, hydrogen, oxygen, nitrogen and magnesium are the major essential nutrients needed by plants. 4 LU_General Biology 1_Module9 Activity 2: Directions: Answer the following questions on a separate sheet of paper. 1. What do plants need for photosynthesis? 2. What are the two stages of photosynthesis? Figure 2: The Light Reactions From the figure below, identify the key players involved in the process. Light Reactions Events 1. Light energy or photon is absorbed by a pigment molecule of the light- harvesting complex of Photosystem II and is passed on to other pigment molecules nearby until the energy makes it to the reaction center. In the reaction center, it is absorbed by the P680 pair of chlorophyll a. 2. The electron in this pair of chlorophyll a is raised to an excited state and is transferred to the primary electron acceptor. P680 loses its electron and becomes positively charged (P680+). 3. The positively charged molecule attracts electrons from a water molecule, resulting to the splitting up of H20 into two electrons, two hydrogen ions (H+), and an oxygen atom with the provision of light energy. The oxygen atom immediately combines with another oxygen atom to form an oxygen molecule (O2) which is then released outside the leaf through the stomata. 4. The excited electrons are then passed on from the primary electron acceptor to the electron carrier molecules through the electron transport chain until they reach Photosystem I. The electron carrier molecules involved here are plastoquinone (Pq), a cytochrome complex, and plastocyanin (Pc). 5 LU_General Biology 1_Module9  5. At each transfer, the electrons release small amounts of energy. This energy is used to pump hydrogen ions across the membrane. The splitting up of water molecules results to an uneven distribution of hydrogen ions in the stroma and the lumen. The H+ ions tries to equalize their distribution by moving from the lumen to the stroma through the aid of a membrane protein called ATP synthase. This is referred to as chemiosmosis. The movement of hydrogen ions through the ATP synthase channel triggers the synthesis of ATP from ADP. The ATP contains high-energy phosphate bonds. 6. Meanwhile, photon is also absorbed and energy is passed on from one pigment molecule to another until the energy reaches the reaction center complex of Photosystem I. The energy excites the electron present in the pair of P700 chlorophyll a located here. The excited electron is then transferred to a primary electron acceptor, making the P700 positively charged and now seeking electrons to fill up the missing ones. This is filled up by the electrons from Photosystem II that are passed on through the electron transport chain. 7. The photo-excited electron from the primary electron acceptor of Photosystem I enters another electron transfer chain, passing the electron to an iron-containing protein called ferredoxin (Fd). 8. An enzyme, the NADP+ reductase, then transfers the electron to NADP+ and stabilizes it by adding a proton (H+) to form NADPH. NADPH is then released to the stroma and becomes part of the Calvin Cycle. Figure 3: Cyclic Electron Flow Cyclic Electron Flow Aside from the usual route of electron flow as described in the events of the light reactions (i.e., noncyclic or linear electron flow), photo- excited electrons may take a short-circuited route which utilizes Photosystem I but not Photosystem II. The ferrodoxin goes back to the cycle and passes the electron to the cytochrome complex and to the Pc 6 LU_General Biology 1_Module9  until it reaches P700 chlorophyll instead of transferring the electron to NADP+reductase. Due to this event, no NADPH is produced but ATP is still synthesized. Activity 2: Directions: Answer the following questions on a separate sheet of paper. 1. If a plant receives only green light, how will this affect photosynthesis? 2. Most carnivorous plants thrive in the dark forest floor. Is there a relationship between carnivory and thriving in the shade? Explore Enrichment Activity 1 Directions: Given the terms below, construct a crossword puzzle. Be sure that you provide a description for each term. Use a separate sheet of paper for your answer. Carbon dioxide Photon Ferredoxin Water P680 NADPH Glucose Plastoquinone Oxygen Plastocyanin Crossword puzzle (20 points) 1 point per term included in the puzzle Descriptions: 1 point per correct description Enrichment Activity 2: Sentence Completion Directions: Complete the sentences below to come up with correct concepts about photosynthesis. (5 pts.) is the process by which green plants harness light energy 7 LU_General Biology 1_Module9 from the sun to convert it to the chemical energy of sugar. The use of and water during photosynthesis results in the manufacture of and oxygen gas (as by-product). Carbon, hydrogen, oxygen, nitrogen, and magnesium are the major essential nutrients needed by plants. Photosynthesis may be divided into two phases: the that occurs in the granum and requires the presence of light energy; and the light-independent phase/Calvin cycle or carbon fixation that occurs in the with or without light. Deepen Directions: Describe the patterns of electron flow through light reaction events by making a diagram. The scoring rubric on will be used in assessing your output. Rubric Diagram Below Average Average Above Average Excellent Score Diagram Few required Some Most required All required components items are required items are items are represented items are represented represented on on diagram represent d on diagram diagram (1-3 points) on diagram (7-8 points) (9-10 points) (4-6 points) Text and Few labels Some labels Most labels All labels are labels (1-3 points) (4-6 points) are present present and and some styles and styles and effects are effects are applied applied (9-10 points) (7-8 points) Creativity Diagram Diagram Creative Highly and appearance appearance diagram creative, shows least meets lesson (7-8 points) exceptional Appearance effort requirements diagram required (4-6 points) (9-10 points) (1-3 points) Total Score 8 LU_General Biology 1_Module9  Lesson Photosynthesis: The Dark Reaction 2 Events/Calvin Cycle Jumpstart Although the generalized equation of photosynthesis shows that light is a requirement, light energy is actually used only during the first phase, which is the light-dependent phase. The light-independent phase involves the use of NADPH and ATP for the conversion of carbon dioxide into carbohydrates. Activity 1: Directions: Analyze the picture and write a short description on it. Figure 4: Two Stages of Photosynthesis 9 LU_General Biology 1_Module9  Discover Core Concepts: a. The sugar that is produced in the Calvin Cycle is not the six- carbon glucose that we are familiar with. This is formed later on. What is produced in the Calvin Cycle is a three-carbon sugar known as G3P or glyceraldehyde-3-phosphate. b. The Calvin Cycle needs to ‘spin’ three times to make one molecule of G3P from three molecules of CO2. Three Phases of Calvin Cycle: Carbon Fixation c. Carbon fixation is a process of incorporating an inorganic carbon molecule, CO2, into an organic material. d. In this phase, the CO2 molecule is attached to a five-carbon sugar molecule named ribulose biphosphate (RuBP) aided by an enzyme named rubisco or RuBP carboxylase. Rubisco is believed to be the most abundant protein in the chloroplast and maybe on Earth. e. The resulting product, a six-carbon sugar, is extremely unstable and immediately splits in half. The split forms two molecules of a 3- phosphoglycerate (3-carbon). Reduction f. A phosphate group (from ATP) is then attached to each 3- phosphoglycerate by an enzyme, forming 1,3-phosphoglycerate. NADPH swoops in and reduces 1,3-biphosphogycerate to G3P. g. For every six G3Ps produced by the Calvin Cycle, five are recycled to regenerate three molecules of RuBP. Only one G3P leaves the cycle to be packaged for use by the cell. h. It will take two molecules of G3P to make one molecule of glucose. i. The ADP and NADP+ that is formed during the Calvin Cycle will be transported back to the thylakoid membrane and will enter the light reactions. Here, they will be ‘recharged’ with energy and become ATP and NADPH. Regeneration of RuBP j. Five molecules of G3P undergo a series of complex enzymatic reactions to form three molecules of RuBP. This costs the cell another three molecules of AT, but also provides another set of RuBP to continue the cycle. 10 LU_General Biology 1_Module9  What happens to G3P after its release from the cycle? k. Two G3Ps can combine together to form either glucose or fructose which are both are six-carbon sugar. l. Glucose and fructose can be combined to form sucrose. m. Glucose can be connected in chains to form starch. n. G3Ps can also be used in lipid and protein synthesis. The cost of making carbohydrate: To make one molecule of G3P, the chloroplast needs: o. 3 molecules of CO2 p. 9 molecules of ATP q. 6 molecules of NADPH Figure 5: The Calvin Cycle 11 LU_General Biology 1_Module9  Explore Enrichment Activity 1 Directions: Label diagram showing the stages of the Calvin cycle. Stage 1: Stage 3: Stage 2: Enrichment Activity 2 Directions: Complete the table below. Calvin Cycle Accounting Per Turn 3 Turns 6 Turns Consume CO2 Consume ATP Consume NADPH Produces G3P Produces Glucose 12 LU_General Biology 1_Module9  Deepen Directions: Describe the significant events of the Calvin by making a diagram. The scoring rubric below will be used in assessing your output. Rubric Above Diagram Below Average Average Excellent Score Average Diagram Few required Some Most All required components items are required required items are represented items are items are represented on on represented represented diagram diagram on diagram on diagram (1-3 points) (4-6 points) (7-8 points) (9-10 points) Text and Few labels Some labels Most All labels are labels labels are present and present and styles and some styles effects are applied and effects are applied (1-3 points) (4-6 points) (7-8 points) (9-10 points) Creativity Diagram Diagram Creative Highly and appearance appearance diagram creative, Appearance shows least meets lesson exceptional effort requirements diagram required (1-3 points) (4-6 points) (7-8 points) (9-10 points) Total Score 13 LU_General Biology 1_Module9  Gauge Directions: Read carefully each item. Use a separate sheet for your answers. Write only the letter of the best answer for each test item in a separate sheet of paper. 1. Which equation describes the chemical reaction of photosynthesis? A. 6 CO2 + 6 H20 C6H12O6 + 6 O2 B. CHO + 02 CO2 + H20 C. CO + HO CHO + O D. CO2 + H20 C6H12O6 + 6 O2 2. Which equation describes the chemical reaction of respiration? A. CO2 + H20 CHO + 02 B. C6H12O6 + 6 O2 6 CO2 + 6 H20 C. CO + HO CHO + O D. C6H12O6 + 6 O2 CO2 + H20 3. Which of the following DOES NOT happen during photosynthesis? A. Carbon dioxide enters the leaf through holes called pistil. B. CO2 combines with the stored energy in the chloroplasts through a chemical reaction to make glucose. C. The sugar is moved through tubes in the leaf to the roots, stems and fruits of the plants. D. Some of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue. 4. Which is true about the photosynthetic pigments? A. There is only one kind of chlorophyll. B. Chlorophyll absorb mostly green light. C. Chlorophyll is required in the Calvin cycle. D. Chlorophyll is formed in the membrane of thylakoids. 5. Which describes carbon fixation? A. The conversion process of inorganic carbon to organic compounds by living organisms. B. The conversion process of organic carbon to inorganic compounds by living organisms. C. It forms a 6-carbon compound immediately converted into 2 three-carbon compounds. D. It forms 5-carbon compound immediately converted into 3 two-carbon compounds 14 LU_General Biology 1_Module9 6. Which describes the regeneration of RuBP? A. The conversion process of inorganic carbon to organic compounds by living organisms. B. The conversion process of organic carbon to inorganic compounds by living organisms. C. It forms a 6-carbon compound immediately converted into 2 three- carbon compounds. D. It forms 5-carbon compound immediately converted into 3 two- carbon compounds 7. Three turns of Calvin cycle are necessary to produce one net gain of PGAL. Five PGAL molecules are required to regenerate 3 molecules of RuBP. During the three turns how many molecules of ATP and NADPH are use up? A. 3, 6 B. 6, 9 C. 9, 6 D. 6, 3 For numbers 8 – 9, refer to the choices inside the box: I. Optimally absorbs photons of wavelength of 700 nm. II. Electron trapped by P 680 are energized by light. III. Responsible in for providing low energy electrons with which to reduce NADP+ to produce NADPH to be used in the Calvin cycle. IV. Electrons are energized by sunlight and passed to a secondary electron acceptor. 8. Which of the following describes Photosystem I? A. I B. III C. II D. IV 9. Which of the following describes Photosystem II? A. I B. II C. III D. IV 10. Which describes carbon fixation? A. The conversion process of inorganic carbon to organic compounds by living organisms. B. The conversion process of organic carbon to inorganic compounds by living organisms. C. It forms a 6-carbon compound immediately converted into 2 three- carbon compounds. D. It forms 5-carbon compound immediately converted into 3 two- carbon compounds. 15 LU_General Biology 1_Module9 11.Which describes the regeneration of RuBP? A. The conversion process of inorganic carbon to organic compounds by living organisms. B. The conversion process of organic carbon to inorganic compounds by living organisms. C. It forms a 6-carbon compound immediately converted into 2 three- carbon compounds. D. It forms 5-carbon compound immediately converted into 3 two- carbon compounds 12. Which describes the second stage of the Calvin cycle? A. The enzyme RuBisCo incorporates carbon dioxide into an organic molecule. B. The organic molecule is reduced. C. RuBP is regenerated. D. None of the above. 13. PGAL is a substance used by plants to make other organic subtances. An example of these organic substances synthesized by plants is glucose. To make one glucose molecule, a 6 – carbon sugar, two molecules of PGAL are linked. How many turns of Calvin cycle is then needed? A. 1 B. 3 C. 6 D. 12 For number 14-15, refer to the choices below: I. ATP and NADPH are continuously produced that then triggers the synthesis of three carbon sugar from carbon dioxide. II. Four hydrogen ions will be added in the thylakoid space that makes the environment high in Hydrogen concentration. III. It is the initial step in the process of photosynthesis by which plants can store energy from sunlight. IV. In this process, light energy is converted to chemical energy in the form of energy reserving molecules ATP and NADPH. 14. Which of the following describes light reaction? A. I and II B. I only C. II and III D. III and IV 15. Which of the following describes light dependent reaction? A.I and II B. I only C. II and III D. III and IV 16 LU_General Biology 1_Module9 Answer Key 17 LU_General Biology 1_Module9 References Printed Materials: Rabago, Lilia M. et al. (2003). Functional Biology Modular Approach. Quezon City, Philippines: Vibal Publishing House, Inc. Ramos, John Donnie A. et al. (2011). Biology Exploring Life Through Science. Queon City, Philippines: Phoenix Publishing House, Inc. Commission on Higher Education. (2016). Teaching Guide for Senior High School General Biology 1 (pp. 120-131). Quezon City, Philippines Website: https://www.biologycorner.com/2020/03/07/the-calvin-cycle/ https://www.slideserve.com/file-download/994787 https://bio.libretexts.org/Bookshelves/Microbiology/Book%3A_Microbiolo gy_(Bou ndless)/5%3A_Microbial_Metabolism/5.11%3A_Phototrophy/5.11C%3A_T he_Two_ Parts_of_Photosynthesis 18 LU_General Biology 1_Module9  For inquiries or feedback, please write or call: Department of Education – SDO La Union Curriculum Implementation Division Learning Resource Management Section Flores St. Catbangen, San Fernando City La Union 2500 Telephone: (072) 607 - 8127 Telefax: (072) 205 - 0046 Email Address: [email protected] [email protected] 19 LU_General Biology 1_Module9