Photosynthesis Material Review PDF

REMINDERS ANNOUNCEMENTS 1. Discussion sections this week will be midterm 2 review. Tuesday, 11/19/24 2. Midterm 2 has two options: Thursday, November 21st Week 8, Day 1 Tuesday, November 26th Photosynthesis/ Material Review TODAY’S AG...

REMINDERS ANNOUNCEMENTS 1. Discussion sections this week will be midterm 2 review. Tuesday, 11/19/24 2. Midterm 2 has two options: Thursday, November 21st Week 8, Day 1 Tuesday, November 26th Photosynthesis/ Material Review TODAY’S AGENDA (8-9:35AM) The Calvin Cycle The Photo part of Photosynthesis: The light reactions C3, C4, and CAM plants Kahoot: Photosynthesis Material Review for Midterm 2  Learning Goals for Today 1 Photosynthesis overview 2 The Calvin Cycle 3 The Photo part of Photosynthesis: The light reactions 4 C3, C4, and CAM plants  The Calvin Cycle Rubisco – one very cool enzyme! Most abundant enzyme on the planet! 10-50% of total leaf protein O2 actually competes with 8 Active Sites CO2 for binding sites Interesting Has 10x the affinity consequences for for CO2 as for O2 C4 & CAM plants Rubisco’s job can best be described as A. Fixing carbon – it’s broken J B. Fixing carbon – removing C from CO2 and connecting the carbon to another molecule à (RuBP) C. Fixing oxygen, removing O2 from CO2 and connecting the oxygen to another molecule.  The Calvin Cycle 3) Regeneration = CO2 1) Carbon fixation = G3P becomes RuMP and carbon binds with RuBP Rubisco uses energy for RuBP to 3PG with the help of Rubisco to be regenerated to start RuBP C-C-C make 2 molecules of 3PG C-C-C-C-C cycle again ATP ATP Calvin Cycle ADP ADP NADPH RuMP NADP+ 2) Reduction = G3P 3PG is reduced to G3P G3P in two step C-C-C C-C-C reaction that uses Glucose energy  The Calvin Cycle Remember à purpose of Calvin Cycle (aka the light independent reactions) is to make sugar (fix carbon) 3 Phases Fixation: CO2 is used to make 3PG (RuBP accepts carbon) Key Enzyme: Rubisco (fixes carbon from CO2) Reduction: 3PG is reduced to G3P Regeneration: RuMP gets regenerated to RuBP RuBP is the CO2 acceptor in Fixation step Don’t need to know all the numbers of molecules – just basic steps. C3 plants… Fixation - Reduction - Regeneration -  Learning Goals for Today 1 Photosynthesis overview 2 The Calvin Cycle 3 The Photo part of Photosynthesis: The light reactions 4 C3, C4, and CAM plants The Light Reactions  The Light Reactions Energy transferred to Reaction Center Light Remember – we need ATP & NADPH for Calvin Cycle Photosystem II – makes ATP Photosystem I – makes NADPH  The Light Reactions PHOTOSYSTEMS II & I Photosystem II uses light to split apart H2O to form O2 and move e- through the electron transport chain and make ATP and later NADPH via NADP+ reductase in Photosystem I In mitochondria: Use energy from glucose to establish a proton gradient. ATP SYNTHASE couples the flow of protons to the production of ATP. In thylakoid: Use energy from light to excite electrons and use the energy from the electron falling back to its ground state to establish a proton gradient. ATP SYNTHASE couples the flow of protons to the production of ATP.  Why is a photosystem like a funnel? Light energy is directed from many photosynthetic pigments (like carotenoids and chlorophyll) and directed to the reaction center Photosystem II vs. Photosystem I Photosystem II (comes first) = uses light energy to split water and make ATP in electron transport chain Photosystem I (comes second) = NADP+ is final electron acceptor to make NADPH Light Both ATP and NADPH are used in the reduction step of the Calvin Cycle Why does energy only travel Carotenoids What happens in the reaction center? toward the reaction center? Chlorophyll B Converting light energy to Resonance transfer moves light Chlorophyll chemical energy by capturing from accessory pigments to A excited electrons for electron chlorophyll a in reaction center Reaction center transport chain  Learning Goals for Today 1 Photosynthesis overview 2 The Calvin Cycle 3 The Photo part of Photosynthesis: The light reactions 4 C3, C4, and CAM plants  What is photorespiration? C4 and CAM plants live in hot, dry climates and have evolved adaptations to prevent photorespiration C3 = C4 = CAM = Barley, coconut, grape, Corn, millet, Agaves, pineapple, palm, peanut, plum, sorghum, sugarcane succulents (cactus), vanilla potatoes, rice, rye, soy, bean, sugar beet, sunflower, wheat  Photorespiration = Rubisco binds to O2 instead of CO2 C3 plants undergo photorespiration but C4 and CAM plants do not C3 Plants – -normal Calvin cycle -Rubisco present in mesophyll cells -Bundle sheath cells do not photosynthesize C4 Plants – -mesophyll cells have PEP – makes oxaloacetate then malate -PEP only binds to CO2 -Bundle sheath cells have Rubisco & photosynthesize, CO2 gets concentrated here *Recall that photorespiration is a plant process in which oxygen is added to Rubisco instead of CO2.  C3, C4 and CAM Plants C3 C4 CAM  C3, C4 and CAM Plants C3 Only uses Rubisco C4 Rubisco and PEP separated in SPACE CAM Rubisco and PEP separated in TIME CO2 CO2 mesophyll cell CO2 PEP PEP oxaloacetate oxaloacetate Rubisco C-C-C-C C-C-C-C malate malate 3PG C-C-C-C C-C-C-C night Calvin C-C-C Cycle day CO2 Rubisco CO2 Rubisco Calvin sugars Calvin Cycle Cycle mesophyll cell sugars sugars bundle-sheath cell mesophyll cell Plant C3 C4 CAM Description Key enzymes Examples Picture Plant C3 C4 CAM Description C4 plants use PEP to fix CO2 CAM plants use PEP to fix CO2 C3 plants use rubisco to fix into four-carbon molecules in into four-carbon molecules at CO2 into three-carbon mesophyll cells which is then night, which is then split into molecules in mesophylls cells split into three-carbon three-carbon compounds the through the Calvin cycle. compounds in bundle-sheath next day for the Calvin Cycle. cells for the Calvin cycle. Key enzymes Rubisco Rubisco, PEP Rubisco, PEP Examples Wheat, rice Corn, sugarcane Succulents, pineapple Picture C4 plants move CO2 molecules to reduce photorespiration, whereas CAM plants decide when to extract CO2 from the environment What does the C in C4 and C3 stand for? Number of carbons that the RuBP + C from CO2 degenerates into à C3 plants = G3P (C-C-C) à C4 plants = oxaloacetate (C-C-C-C) + malate (C-C-C-C) Why are CAM and C4 plants able to live in hotter dryer environments compared to C3 plants? They have another enzyme to fix carbon when stomata are closed: PEP carboxylase PEP only binds to CO2 (Rubisco can bind to O2 for photorespiration) What does it mean to say that CAM separate rubisco* and PEP in time and C4 separate them in space? *All plants C4 = PEP is in mesophyll cells and CAM = Both PEP and rubisco are in have rubisco rubisco is in bundle-sheath cells mesophyll cells but PEP is used at night (C3, C4, CAM) and rubisco is used during the day Is a plant either CAM, C4, C3 or can it be all three? A plant can only be one type but some C3 plants can adopt a CAM pathway depending on environmental factors like temperature or precipitation early in development Kahoot Review: Photosynthesis  5-min Break! Attendance Time Scan the QR code or go to https://tinyurl.com/W8D1plantreview to answer the following question: Q: What do photosystem II and I produce, respectively? (This will be used for taking attendance today.)  Animal Development Describe the difference between determination and differentiation Explain and give examples of differential gene expression (DGE) Describe cytoplasmic segregation and induction and give explanations for how these can lead to DGE Draw a graphical representation of how a morphogen gradient works Describe morphogen gradient of AP axis development in Drosophila Correctly predict outcome of various mutants in AP development in Drosophila Define hox genes and what they do  Plant Structure and Function List plant cell types and tissues and give physical properties and examples of each Diagram the cross section of a leaf, stem and root. Know the key differences in plant tissues organization in monocots and eudicots. Describe the function and location of meristems Describe the pattern of secondary growth (lateral meristems) in plants (wood growth) Explain why plants rely more on cell expansion rather than cell division in comparison with animals  Water and Sugar Transport in Plants Write and use the water potential equation Describe the components of water potential (solute potential and pressure potential) and correctly identify what is contributing to each of those Draw and summarize how guard cells open and close including the role of water potential in this process Describe the components of the transpiration-cohesion-tension theory Describe how water is transported in a plant Correctly state that water is pulled up a plant not pushed up a plant (WHY) Predict changes in water potential in xylem and phloem as sugars are transported Describe the difference between apoplastic and symplastic movement and correctly state why symplastic movement is slower than apoplastic movement. Water potential = solute potential + pressure potential Ψ = Ψs + Ψp  Plant Nutrition Say where most of the carbon in a plant comes from (CO2) Define a mutualism, (specifically arbuscular mycorrhizae, rhizobacteria) Explain what each partner gets out of the mutualism Should be able to describe why nitrogen fixation is difficult for plants (triple bond is hard to break; plants don’t have the right enzyme to do this) Know that plants don’t fix nitrogen – bacteria fix nitrogen  Plant Growth and Regulation Identify where light is detected in plants Explain why auxin only travels in one direction (Auxin polar transport) What happens if auxin transporters are inhibited? What happens with directional light? Explain how auxin leads to cell growth in plants (acid growth hypothesis) Explain what would happen if proton pumps were inhibited How does auxin influence transcription? What role does water potential play in this process? Link the steps between phototropism, movement of auxin, and acid growth Understand that phototropism is due to cells enlarging, not dividing  Photosynthesis State the products and reactants for photosynthesis as a whole State the products and reactants for the Calvin Cycle and the light reactions Where do the electrons come from? What is water used for? Where is oxygen coming from? Describe the purpose and mechanism of a photosystem What is the role of chlorophyll? Why is a photosystem like an antennae? What happens in the reaction center? State the role of rubisco (it is what fixes carbon)