GB1_Q2_Week-2a Biology 1 Past Paper PDF

WEEKLY LEARNING ACTIVITY SHEETS Biology 1 Quarter 2 Week 2A ENERGY TRANSFORMATION (LIGHT REACTIONS) Learning Competency: Describe the patterns of electron flow through light reaction events. (STEM_BIO11/12-IIa-j-4) Specific Objectives:...

WEEKLY LEARNING ACTIVITY SHEETS Biology 1 Quarter 2 Week 2A ENERGY TRANSFORMATION (LIGHT REACTIONS) Learning Competency: Describe the patterns of electron flow through light reaction events. (STEM_BIO11/12-IIa-j-4) Specific Objectives: 1. Determine the essential molecules involved in the light reactions; 2. Describe the events and processes happening during light reactions; and 3. Distinguish the importance of sunlight to photosynthesis. Key Concepts  Why is photosynthesis important? Photosynthesis is a vital process in which life here on Earth largely depends. As autotrophs, plants can make their food with raw materials from water, carbon dioxide, and sunlight. On the other hand, humans and other living organisms depend on plants to survive since they cannot make their food. If photosynthesis is stopped, there would soon be little food or other organic matter on Earth. Then, most organisms would disappear, and in time Earth's atmosphere would have no amount of oxygen in the air. The only organisms that could probably exist under Figure 1. Photosynthesis inside the leaf showing how such conditions would be the chemosynthetic raw materials transform to products beneficial bacteria, which uses certain inorganic Source: to the living organisms on Earth. compounds' chemical energy and are not https://vdinh.weebly.com/uploads/1/3/5/5/13557835/74016 dependent on light energy conversion. Thus, it 3.png?421 is deemed essential to understanding a vital process for the sustenance of life, photosynthesis.  Stages of Photosynthesis Photosynthesis happens in a two-way process. These include the light reaction stage and the dark reaction stage or the Calvin Cycle. Stage one: Light reactions Light reactions use sunlight to start with the electron transfer. Light reduces Nicotinamide Adenine Dinucleotide Phosphate (NADP+) to Nicotinamide Adenine Dinucleotide Phosphate Hydrogen (NADPH) and splits water producing oxygen as a by- product. This results to form Adenosine Triphosphate (ATP) through phosphorylation. This process takes place in the thylakoids inside the chloroplast. Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] Page 1 Products of the Light Reactions The product of light reactions is Hydrogen and ATP. These are then transferred to the second stage of photosynthesis, the Calvin Cycle. The mitochondria of plant cells can use some of the oxygen produced by this process for aerobic respiration. However, most oxygen diffuses out of plant cells and out of the leaves through the stomata. Increasing the concentration of oxygen in the Earth's atmosphere is the overall effect of photosynthesis. Stage Two: Calvin Cycle or Dark Reactions Calvin Cycle is the second stage in the light reaction. This is sometimes referred to as 'dark reactions' because it does not need light energy for its processes to happen. This stage requires energy supplied by the Adenosine Triphosphate (ATP) made during the light reactions. Then, ATP is broken down to release energy used to combine hydrogen (from the light reactions) with carbon dioxide to produce Glucose (C6H1206) which is a sugar. Specific enzymes control the reactions of carbon fixation. This stage takes place in the stroma inside the chloroplast. After the energy transfer, the energy carrier molecule returns Adenosine Diphosphate (ADP), inorganic phosphate, and NADP+ to the light reactions. Light Reactions Events Figure 2. The Light Reactions Photo Source: Domingo, Doreen. et al., Teaching Guide for Senior High School in Biology 1, 2016 The process starts when light energy or photons 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. 1. In this pair of chlorophyll, the electron is raised to an excited state and is transferred to the primary electron acceptor. Then P680 loses its electron and becomes positively charged (P680+). Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] Page 2  2. The positively charged molecule, P680+ attracts electrons from a water molecule, resulting in the splitting up of water H20 into two electrons, the two hydrogen ions (H+), and an oxygen atom with the supply of light energy. The oxygen atom immediately combines with another oxygen atom to form an oxygen molecule (O2), then released outside the leaf through the stomata. 3. Inside the stroma, 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 are plastoquinone Figure 3. Flow of electrons during the light (Pq), a cytochrome complex, and reaction stage of photosynthesis. Arrows plastocyanin (Pc). pointing upward represent light reactions that increase the chemical potential, and arrows slanting downward represent the 4. At every transfer of electrons, these release flow of electrons via carriers in the small amounts of energy. Then, this energy is membrane. Photo Source: Encyclopædia Britannica, Inc. used to pump hydrogen ions across the membrane. The splitting up of water molecules makes an uneven distribution of hydrogen ions in the stroma and the lumen. Through the aid of a membrane protein called ATP synthase, the H+ ions try to equalize their distribution by transferring from the lumen to the stroma. This process is called chemiosmosis. The transfer of hydrogen ions through the ATP synthase channel causes the production of ATP from ADP. ATP contains high-energy phosphate bonds. 5. Meanwhile, when a photon is absorbed and energy is passed on from one pigment molecule to another, the energy reaches the reaction center complex of Photosystem I. The energy excites the electron present in the pair of P700 chlorophyll located here. The excited electron is then moved to a primary electron acceptor, making the P700 positively charged and seeking electrons to fill up the missing ones. The electrons from Photosystem II fill this up passed on through the electron transport chain. 6. As the photo-excited electron from the Figure 4. Chemiosmosis: In oxidative primary electron acceptor of Photosystem I phosphorylation, the hydrogen ion gradient formed by the electron transport chain is used by enters another electron transfer chain, it ATP synthase to form ATP. passes the electron to an iron-containing Photo Source: shorturl.at/eCF78 protein called ferredoxin (Fd). 7. Lastly, 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. Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] Page 3   Cyclic Electron Flow Aside from the usual electron flow route described in the events of the light reactions, photo-excited electrons may take a short-circuited path which utilizes Photosystem I but not Photosystem II. The ferredoxin goes back to the cycle and passes the electron to the cytochrome complex and the plastocyanin (Pc). until it reaches P700 chlorophyll instead of transferring the electron to NADP+ reductase. Because of this, no Figure 5. The Cyclic Electron Flow NADPH is produced, but ATP is still Photo Source: Domingo, Doreen. et al., Teaching Guide for Senior High School synthesized. in Biology 1, 2016 Exercises/ Activities Activity 1. Let there be Light! Objective: Determine the essential molecules involved in the light reactions. What to do: Accomplish the diagram below with the essential molecules involved in the light dependent reactions. Fill in the empty shapes with the names of the molecules involved in the processes. Write your answers clearly on a separate answer sheet. Choose your answer from the box. P700 P680 O2 H 20 PQ LIGHT NADP+ ATP PRIMARY PRIMARY CYTOCHROME PC FD NADPH H2 ACCEPTOR RECEPTOR COMPLEX Photo Source: Domingo, Doreen. et al., Teaching Guide for Senior High School in Biology 1, 2016 Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] Page 4 Guide Questions Directions: Conduct research and answer the following questions guided by the rubric below. Write your answers on the answer sheet. 1. What do you think is the importance of the Cyclic Electron Flow to the process of photosynthesis and the cell? 2. How do plants convert light energy into chemical energy? Rubric for Grading Explanation: Points Performance Established an accurate and complete understanding of the question: answers the 5 question, gives a relevant, justifiable answer; and states arguments in a logical order. Established accurate but only adequate understanding of question because it does not 3 back conclusions with warrants and data. Does not give an understanding of the question. 1 It does not provide evidence to support their answer to the question. Activity 2. Light- REACTION- Action! In a process called non-cyclic photophosphorylation or the "standard" form of the light- dependent reactions, electrons are removed from water and passed through Photosystem II (PS II) and Photosystem I (PS I) before ending up in NADPH. This process requires light to be absorbed twice, once in each photosystem, and it makes ATP. In this activity, you are going to familiarize the steps involved in the light reactions. Objective: Describe the events and processes happening during light reactions. What you need: Pen and paper What to do: Describe the events and processes during the light reactions by labeling the parts of the diagram below. Write the letter of your answer. Photo Source: https://www.khanacademy.org/science/ap-biology/cellular-energetics/photosynthesis/a/light-dependent-reactions Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] Page 5  a. NADPH formation. The high-energy electron travels down a short second leg of the electron transport chain. At the end of the chain, the electron is passed to NADP+ (along with a second electron from the same pathway) to make NADPH. b. ATP synthesis. The high-energy electron travels down an electron transport chain, losing energy as it goes. Some of the released energy drives pumping of H+ ions from the stroma into the thylakoid interior, building a gradient (H+ ions from the splitting of water also add to the gradient.) As H+ ions flow down their gradient and into the stroma, they pass through ATP synthase, driving ATP production in a process known as chemiosmosis. c. Light absorption in Photosystem I (PS I). The electron arrives at photosystem I and joins the P700 special pair of chlorophylls in the reaction center. When light energy is absorbed by pigments and passed inward to the reaction center, the electron in P700 is boosted to a very high energy level and transferred to an acceptor molecule. The special pair's missing electron is replaced by a new electron from Photosystem II (PS II) (arriving via the electron transport chain). d. Light absorption in Photosystem II (PS II). When light is absorbed by one of the many pigments in Photosystem II, energy is passed inward from pigment to pigment until it reaches the reaction center. There, energy is transferred to P680, boosting an electron to a high energy level. The high-energy electron is passed to an acceptor molecule and replaced with an electron from water. This splitting of water releases the O2 we breathe. Activity 3. When Light Gives Life Photosynthesis is the process through which plants use energy from the sun to turn water, carbon dioxide, and minerals into glucose (food) and oxygen. This process is so important to life on Earth! Not only do animals eat plants, but they also breathe in the oxygen produced by the plants. When the animals exhale, they provide carbon dioxide in return that can be used by the plants for more photosynthesis. In this exercise, you will observe the photosynthesis process taking place in alugbati leaves. You will provide the alugbati with carbon dioxide, and observe how light completes the process when these leaf disks release tiny oxygen bubbles. Objective: To distinguish the importance of sunlight to photosynthesis. What you need: fresh alugbati (Basella alba) leaves (any leaf with broad and flat margin) hole puncher (or can use hard plastic straw) baking soda (sodium bicarbonate) liquid dishwashing detergent (only need a drop) 1 plastic syringe (no needle, 10 mL or larger) 2 clear cups 1 measuring cup 1 measuring spoon (1/8 teaspoon) light source (natural sunlight works, or you can use an artificial light) Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] Page 6 What to do: 1. Use a measuring spoon to scoop out 1/8 teaspoon of baking soda, and fill your measuring cup with 300 milliliters of water. Mix the baking soda into the water to create your bicarbonate solution. When the baking soda dissolves in the water, it releases carbon dioxide. This will be used by the alugbati for photosynthesis. Pour this solution into any cup and set aside. 2. Fill your clean measuring cup with 200 milliliters of water and add a drop of liquid dishwashing detergent to Photo Source: https://bit.ly/3mAZrvM create a detergent solution. 3. Pour half (150mL) of your bicarbonate solution (from step 1) into a clear cup. Place a drop of the detergent solution into the bicarbonate solution. Make sure there are no bubbles that form on top of the water. If you see bubbles, continue adding small amounts of the bicarbonate solution to the cup until the bubbles are gone. 4. Using the hole puncher, create 10 – 20 discs from the alugbati (Basella alba) leaves. Only punch holes in smooth, flat areas and do your best to avoid large veins Photo Source: https://bit.ly/3mAZrvM or the edges of the leaf. 5. Remove the plunger from the syringe and add the discs into the syringe. 6. Put the plunger back into the syringe and slowly depress it to expel as much air as you can without crushing the leaves. 7. Dip the tip of the syringe in the bicarbonate/detergent mixture and pull in about 3 mL of liquid. Gently tap the syringe to suspend the leaves in the solution. 8. Next, place your finger over the end of the syringe and pull back on the plunger to create a vacuum. Photo Source: https://bit.ly/3mAZrvM 9. While keeping your finger over the tip to maintain the vacuum, swirl the leaf disks in the syringe. After 10 seconds, remove your finger to release the vacuum. 10. Repeat steps 8 and 9 to make sure the leaves take up the carbon dioxide. You should observe the discs sinking to the bottom of the syringe. If this does not happen, you may need to start over using fresh discs and new solution that has more baking soda. 11. Pour the discs into the cup with the bicarbonate/detergent mixture and watch them sink to the bottom. Make sure they don’t stick to the sides of the cup. Photo Source: 12. Expose the cup to natural sunlight or artificial light source for several https://bit.ly/3mAZrvM minutes. Observe and write down what happens as the alugbati discs perform photosynthesis and give off oxygen. Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] 7 Guide Questions Directions: Answer the following questions with only 2 to 3 sentences guided by the rubric below. Write your answers on the answer sheet. 1. What happened to the alugbati (Basella alba) discs as they gave off oxygen from photosynthesis? 2. What will happen to the alugbati (Basella alba) discs when you turn off the light source? 3. Why does the alugbati (Basella alba) leaves photosynthesized? Rubric for Grading Explanation: Points Performance Established an accurate and complete understanding of the question: answers the 5 question, gives a relevant, justifiable answer; and states arguments in a logical order. Established accurate but only adequate understanding of question because it does 4 not back conclusions with warrants and data. Does not give an understanding of the question. 3 It does not provide evidence to support their answer to the question. Reflection Directions: Please put a check mark in the column that corresponds to your answer. 1. Which of the concepts listed in the table below interest you the most? the least? Most Least Concepts Interesting Interesting Importance of photosynthesis Stages of photosynthesis. Simulation of photosynthesis using leaf disc. Directions: Write your answer in two sentences in a separate sheet of paper. 1. Did the activities help you understand the topic? (Yes/No) Explain your answer. 2. What is the significance/connection of the topic in your life or in your daily life activities? References: A. Book Source Jane Reece, et al., Campbell Biology 10th Edition. (San Francisco, California: Pearson Benjamin Cummings,2010), 190 – 194. Cecie Starr, Biology: Concepts and Applications 5th Edition (Belmont, California: Brooks/Cole- Tomson Learning, 2003), 98-100. B. Internet Sources BBC Bitesize. “Photosynthesis”. Accessed October 31, 2020. Retrieved from: https://www.bbc. co.uk /bitesize/guides/zcktw6f/revision/3 Biology Libretexts. “Chemiosmosis and Oxidative Phosphorylation”. Last updated August 15, 2020. https://bit.ly/3m3iM8H Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] 8 Deeptirekha Jain. “Experiment to Prove Light is Essential for Photosynthesis, Biology Discussion”. Accessed November 1, 2020. https://bit.ly/3fDW9oU Gabi Slizewska. “Sunlight in Photosynthesis — Role & Importance”. Last updated 2019. https://bit.ly/3fDW9oU. James Alan Bassham et al. “Photosynthesis (Biology”. Last updated March 17 2020. https://www.britannica.com/science/photosynthesis Image References Figure 1.https://vdinh.weebly.com/uploads/1/3/5/5/13557835/740163.png?421 Figure 2. Domingo, Doreen. et al., Teaching Guide for Senior High School in Biology 1, 2016 Figure 3. Encyclopædia Britannica, Inc. Figure 4. shorturl.at/eCF78 Figure 5. Domingo, Doreen. et al., Teaching Guide for Senior High School in Biology 1, 2016 Light Reactions diagram. https://www.khanacademy.org/science/ap-biology/cellular- energetics/photosynthesis/a/light-dependent-reactions Activity images. https://bit.ly/3mAZrvM Answer Key 15. NADPH 14. NADP+ 13. FD 12 PRIMARY ACCEPTOR sinks. 11. P700 The leaf disk 2. 10. PC floats. 9. ATP The leaf disk 1. COMPLEX 8. CYTOCHROME Gives Life 7. PQ Activity 3. When Light 6. PRIMARY RECEPTOR 5. H20 4 H2 4. A 3. O2 3. D 2. P680 2. B 1. LIGHT 1. C REACTION- Action! Light! Activity 2. Light- Activity 1. Let there be Author: MARJORIE T. CHIONG-BERMUDEZ School/Station: KITCHARAO NATIONAL HIGH SCHOOL (Senior High School) Division: AGUSAN DEL NORTE email address: [email protected] or [email protected] 9