General Biology 1 12 STEM PDF

GENERAL BIOLOGY 1 12 STEM General Biology 11/2 Science, Technology, Engineering, and Mathematics ACTIVITY 1: What is the vital role of the Sun to organisms in our Planet? WEEK 3 Part A: Light-Dependent Reactions MELC: (STEM_BIO11/12-IIa-j-4) Describe...

GENERAL BIOLOGY 1 12 STEM General Biology 11/2 Science, Technology, Engineering, and Mathematics ACTIVITY 1: What is the vital role of the Sun to organisms in our Planet? WEEK 3 Part A: Light-Dependent Reactions MELC: (STEM_BIO11/12-IIa-j-4) Describe the patterns of electron flow through light reaction events General Biology 11/2 Science, Technology, Engineering, and Mathematics  Learning Objectives At the end of the lesson, you should be able to do the following: A. explain the processes of light-dependent reactions during photosynthesis; B. describe the flow of electrons during light reactions; C. differentiate the cyclic and noncyclic pathways of light reactions; ACTIVITY 2: Analyze the process of photosynthesis in the picture. What are the reactants and products on this process as a chemical reaction? ACTIVITY 2: Reactants Products Why does plants are called autotrophs?  Stages of Photosynthesis Photosynthesis is a series of chemical reactions that convert carbon dioxide and water into glucose (sugar) and oxygen in the presence/absence of the sunlight. Light-dependent Light-independent reaction reaction  Stages of Photosynthesis Photosynthesis takes place in the Chloroplast. EXERCISE 1:  EXERCISE 1: Guide Questions: 1. What is the role of the photosystems in the thylakoid membrane of the chloroplast. 2. Describe the flow of electrons in the thylakoid membrane. 3. How can you describe “photolysis”? 4. What is the important role of the ATP synthase during light-dependent reactions? 5. What are the 3 important products after a process of light- dependent-reaction? Light-dependent Reactions The light-dependent reactions (or simply light reactions) are named so because they only occur when solar energy is available. Light-dependent Reactions This process happens on the thylakoid membrane of chloroplasts which converts solar energy into chemical energy. Light-dependent Reactions The chlorophyll in the thylakoid capture kinetic energy from photons and store it as potential energy in the chemical bonds of two molecules, ATP and NADPH. Photon = particle of light which is composed of electromagnetic energy. Light-dependent Reactions The chlorophyll replaces its “lost” electrons by splitting water molecules by the influenced of light (also known photolysis). LIGHT-DEPENDENT REACTIONS The splitting of water molecules yield oxygen as a waste product. How do electrons move and produce ATP during light-dependent reactions?  Electron Flow in Light Reaction Thylakoid membrane Photosystem I and Photosystem II are the two multi-protein complexes that contain the pigments necessary to harvest photons.  Electron Flow in Light Reaction Thylakoid membrane Photosystem I (P700) and Photosystem II (P680) are composed of Light- harvesting Complexes (LHC) or reaction centers that absorb different wavelengths of light. Electron Flow in Light Reaction Light striking photosystem II excites two electrons (gaining energy & release heat). Electron Flow in Light Reaction What will happen to the excited electrons? The “excited” electrons are ejected from the chlorophyll a reaction center / photosystem II and will grabbed by the first protein in the electron transport chain that links the two photosystems. Electron Flow in Light Reaction The two excited electrons are replaced by electrons from the photolysis of water molecules when water splits into oxygen gas (O2) and two protons (H+). Electron Flow in Light Reaction As the electrons continue to move in the electron transport chain, their energy is used to pump protons (H+) from the stroma across the membrane into the thylakoid lumen or space. Electron Flow in Light Reaction The diffusion of H+ will rotate the ATP synthase, which drives the production of ATP molecules. Electron Flow in Light Reaction Photosystem I functions as much as photosystem II does as it forms NADPH that are used in light-independent reaction. Electron Flow in Light Reaction The reactive chlorophyll molecule ejects electrons to an electron carrier molecule in the second electron transport chain in the thylakoid membrane. Electron Flow in Light Reaction The boosted electrons in photosystem I are then replaced with electrons passing down from the first electron transport chain from photosystem II. Electron Flow in Light Reaction The second electron transport chain passes the electrons to a molecule of NADP+, reducing it to NADPH. Electron Flow in Light Reaction What are the products of the light-dependent reaction? The products of light- dependent reactions are oxygen, ATP, and NADPH. The ATP, and NADPH will be used on the second stage of photsynthesis.  How does the noncyclic pathway of light-dependent reactions differ from the cyclic pathway?  Cyclic & Noncyclic Pathways What is the difference between cyclic & noncyclic pathway of light-dependent reaction? Cyclic Pathway Nonyclic Pathway A pathway wherein the A pathway wherein electrons return to the same electrons from PSII are used photosystem. by PSI. This only happens in the It happens in both PSI and electron transport photosystems I and II. chain. Both NADPH & ATP are Only ATP is produced. produced. ATP Generation in Light-Dependent Reactions Summary of the Light-Dependent Reactions Molecules and Energy Involved 12H2O + 12NADP+ + 18ADP + 18Pi + Input light energy and chlorophyll Output 6O2 + 12NADPH + 18ATP photosynthesis Reactants Products  EXERCISE 2: DIRECTIONS: Identify the terms being described by the following statements. 1. The stage of photosynthesis happens in the thylakoid membrane, where solar energy is converted into chemical energy. LIGHT-DEPENDENT REACTION 2. These protein complexes are consisting of several light-harvesting complexes surrounding a reaction-center complex. PHOTOSYSTEMS 3. The process that involves the breakdown or decomposition of a molecule by using light energy. PHOTOLYSIS 4. A photosynthetic pathway which involves two photosystems working together to synthesize ATP. NONCYCLIC PATHWAY 5. A photosynthetic pathway which involves only the photosystem I and the electron transport chain. CYCLIC PATHWAY WEEK 3 Part B: Light-Independent Reactions MELC: (STEM_BIO11/12-IIa-j-5) Describe the significant events of the Calvin Cycle. General Biology 11/2 Science, Technology, Engineering, and Mathematics  Learning Objectives At the end of the lesson, you should be able to do the following: A. elucidate the different phases of the Calvin Cycle; B. identify the different factors that affect the phases of the Calvin cycle. C. determine the inputs and outputs of photosynthesis in both light-dependent and light- independent reactions; and D. simulate the process of photosynthesis.  Light-independent Reactions Light reactions take place in the thylakoids while Calvin Cycle takes place in the stroma. ACTIVITY 3: How do you think Photosynthesis happens in the absence of light? ACTIVITY 4:  ACTIVITY 4: Guide Questions: 1. In which part of the chloroplast do light-independent reaction takes place? 2. What are the stages of the Calvin cycle? Describe each stage. 3. What molecule is primarily involved in the first stage of the Calvin cycle and where it enters in the leaf of a plant? 4. In which stage of the Calvin cycle do ATP and NADPH from light reactions are used? 5. In total, how many turns should take place in the Calvin cycle to create a glucose molecule? Light-independent Reactions The light-independent reactions (Calvin cycle) are named so because energy from photons is not directly required for the chemical reactions to proceed. Light-independent Reactions What products of light- dependent reactions are utilized in the Calvin Cycle? The light-independent reactions run on the ATP and NADPH molecules generated from light- dependent reactions. Light-independent Reactions Carbon dioxide comes from the atmosphere & enter via the stomata of leaves. 42 Light-independent Reactions What is the main product of light-independent reaction? The light-independent reactions ultimately produce glucose, a sugar, in the fluid-filled stroma of chloroplasts.  How are the three main phases of the Calvin cycle different from each other? Phases Of Light-independent Reactions 45 Phases Of Light-independent Reactions Phase 1 is termed as Carbon fixation because the process involves incorporating Carbon atoms from an inorganic source into an organic molecule. Phase 1: Carbon Fixation Phases Of Light-independent Reactions Ribulose 1,5-bisphosphate (RuBP) Ribulose 1,5-bisphosphate carboxylase-oxygenase The enzyme RuBisCo catalyzes the reaction between the carbon dioxide and the five-carbon sugar Phase 1: Carbon Fixation RuBP. Phases Of Light-independent Reactions Ribulose 1,5-bisphosphate (RuBP) Ribulose 1,5-bisphosphate carboxylase-oxygenase Phase 1 results in the formation of an unstable six-carbon molecule, which spontaneously splits into two Phase 1: Carbon Fixation 3-PG. Phases Of Light-independent Reactions Phase 2 is termed as reduction because the process involves the gain of electrons Phase 2: Reduction 3-PG from the NADPH (reduced ). Phases Of Light-independent Reactions Glyceraldehyde 3-phosphate ATP and electrons donated from NADPH reduce molecules of Phase 2: Reduction 3-PG into G3P. 50 Phases Of Light-independent Reactions After the reduction process, one phosphate group and electrons are transferred to the G3P, thus, also forming ADP and NADP+. These will return to light- dependent reactions for them to be reenergized. Phase 2: Reduction  Phases Of Light-independent Reactions Phase 3 is termed as regeneration because the process involves regenerating RuBP. Phase 3: Regeneration  Phases Of Light-independent Reactions When three molecules of Carbon dioxide enter the cycle, six G3P molecules are made. One exits the cycle and is used to make glucose, while the other five must be recycled to regenerate three molecules of the RuBP acceptor. Phase 3: Regeneration  Phases Of Light-independent Reactions Since six CO2 molecules are needed in the production of one glucose, the Calvin cycle should take 6 turns. Phase 3: Regeneration PHASES OF LIGHT-INDEPENDENT REACTIONS 55  Summary of the chemical reactions in Photosynthesis Region of chloroplast Chemical Reactions Thylakoid (light- 12H2O + 18ADP + 18Pi + 12NADP+ → 6O2+ 18ATP + dependent) 12NADPH Stroma (light- 6CO2 + 18ATP + 12NADPH → C6H12O6 + 18ADP +18Pi + independent) 12NADP+ Overall Photosynthetic 6CO2 + 6H2O + 18ATP + 12NADPH → C6H12O6 + 6O2 Reaction  EXERCISE 3: DIRECTIONS: Identify the terms being described by the following statements. 1. This enzyme-mediated stage of photosynthesis makes glucose in the stroma of chloroplasts. CALVIN CYCLE 2. This phase of light-independent reactions incorporates carbon atoms from an inorganic source into an organic molecule. CARBON-FIXATION 3. This phase of light-independent reactions includes the reaction between phosphoglycerate and NADPH. REDUCTION 4. This phase aims to resynthesize RuBP to prepare for succeeding carbon fixation reactions. REGENERATION 5. This molecule is produced after the reaction of 3PG with ATP and NADPH. GLYCERALDEHYDE-3-PHOSPHATE (G3P) Let’s Sum It Up!