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AP Biology: Tuesday, 11/22/11 Intro to Photosynthesis. Homework: Chapter 10 Reading Worksheet – take notes on this for tomorrow Do Now: Hand in PS 9 Answer the following in your notebook: Which stage of cell respiration do you think EVOLVED first? Why?
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AP Biology: Tuesday, 11/22/11Intro to Photosynthesis • Homework: • Chapter 10 Reading Worksheet – take notes on this for tomorrow • Do Now: • Hand in PS 9 • Answer the following in your notebook: • Which stage of cell respiration do you think EVOLVED first? Why? • What do you know about the summary equation for photosynthesis? Can you write it? How does it relate to the equation for cell respiration? • Goals for Today: • Explain the order of evolution of methods for using and making sugar • Identify the pigments and light wavelengths necessary for photosynthesis, and use an absorption spectrum to explain which wavelengths of light best promote photosynthesis
Evolution of glucose pathways: • Glycolysis – slow, makes a little ATP from the glucose in the “primordial soup” • Photosynthesis • Creates lots of glucose to fuel glycolysis • Creates oxygen… • Aerobic Cell Respiration
Photosynthesis Carbon dioxide + Water + Sunlight energy Glucose + Oxygen
Photosynthesis:Sunlight meetsChlorophyll • Visible Light Spectrum • Pigments • Chlorophyll • Absorption Spectrum Goals: • Identify the pigments and light wavelengths necessary for photosynthesis • Use an absorption spectrum to explain which wavelengths of light best promote photosynthesis
In a group of 3-4: • Choose a scribe to record answers. Discuss and write down: • Why are plants green? • Which color(s) of light would result in the most photosynthesis? • Which color(s) would result in the least photosynthesis? • How could you set up an experiment to test this?
AP Bio: Wednesday, 11/23/11Photosynthesis • Homework: • PS 10 due Thursday after break • Do Now: • Take out the Photosynthesis Reading Worksheet • Get back and look over your quiz • Goals for Today: • Describe the details of the two stages of photosynthesis • How light energy is converted into chemical energy • How that energy is used to make glucose
Summary of Photosynthesis: Overall equation: 6CO2 + 6H2O + sunlight energy C6H12O6 + 6O2 reduction oxidation
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Phase 1: The Light Reactions stroma cytochromes (electron transport proteins) NADP+ reductase LIGHT LIGHT H+ e- NADP+ e- e- e- NADPH e- e- e- e- PS I e- PS II H2O thylakoid space ½ O2 + 2 H+ H+ to Calvin Cycle ATP synthase ADP ATP Pi H+
Summary of Light Reactions: • Water splits to donate electrons, and releases oxygen as waste • Light excites electrons to flow through ETC made of chlorophylls (photosystems) and cytochromes • ATP and NADPH are made (for use in the Calvin cycle)
Summary of Calvin Cycle: • Carbon (from CO2) is fixed by the enzyme Rubisco • Most fixed carbon is used to regenerate RuBP (the CO2 acceptor that starts the cycle) • Some fixed carbon is used to make a 3-carbon sugar that can form… • glucose (used for cell resp. or stored as starch) • sucrose (transported through rest of plant) [This is the whole point of photosynthesis!]
AP Bio: Monday, 11.29.10Photosynthesis: Challenges & Adaptations • Homework: • PS 10 due tomorrow • Do Now: • Read the Background Info and answer questions 1-2 on the handout • Goals for Today: • Describe photorespiration and explain why it’s bad for plants • Explain how C4 and CAM photosynthesis get around the challenge of photorespiration • Agenda: • Do Now • Quick explanation of photorespiration • Work in groups on C4 or CAM • If time: Present on C4 or CAM. If not, tomorrow.
Photorespiration – • The process in which the enzyme Rubisco fixes oxygen instead of carbon dioxide (in the first step of the Calvin cycle) • Due to Rubisco’s lack of specificity (it can use O2 or CO2 as a substrate) • Happens when stomates are closed (high O2 concentration and low CO2 concentration) • Wasteful – uses ATP and NADPH from light rxns, but makes no sugar!
Photosynthesis: Challenges & Adaptations • Goals for Today: • Describe photorespiration and explain why it’s bad for plants • Explain how C4 and CAM photosynthesis get around the challenge of photorespiration • In Groups of 3: • Use a textbook to figure out how C4 or CAM works to circumvent photorespiration • Answer the questions on your assigned page • Every member of your group should be ready to explain this to the class!
AP Bio: Tuesday, 11.30.10Photosynthesis: Challenges & Adaptations • Homework: • Lab 4 Pre-Lab (read procedure and answer pre-lab questions) • Do Now: (in your mind or your notebook) • What photosynthesis adaptation did your group study? • Both of these adaptations separate the initial step of carbon fixation from the actual Calvin cycle. Does your adaptation separate these things temporallyor spatially? • Goals for Today: • Explain how C4 and CAM photosynthesis get around the challenge of photorespiration • Agenda: • C4 and CAM presentations • Pre-Lab for Lab 4
AP Bio: Wednesday, 12.1.10Lab 4: Rates of Photosynthesis • Homework: • Lab 4 Graph and Analysis Questions • Do Now: • Take out Lab 4 • Goals for Today: • Predict and measure how _____ and __________ affect rates of photosynthesis • Explain how our experimental setup allows us to do this • Agenda: • Review Pre-Lab and experiment set-up • Set up chloroplast suspension • Do the lab!
Lab Groups for Today: • Surendra • Wilmene • Sohaila • Wilanda • Tracy • Leo • Elias • Hannah • Eliza • Sayed • Yanira • Alex Set up tubes now and come back 3rd or 4th period: • Gina • Shannon • Elaine • John • Cameron • Maria • Peter • Ned • Betsie • Juliana
AP Bio: Thursday, 12.2.10Cell Energetics Wrap-Up & Review • Homework: • Study for Test on Cell Respiration & Photosynthesis • Do Now: • Sit with your lab group from yesterday (but at the desks and front tables) • Take out Lab 4 • Volunteers draw graphs on the board • Goals for Today: • Explain the results of the photosynthesis lab • Compare and contrast cell respiration and photosynthesis • Review Cell Energetics by playing Jeopardy!
Compare/Contrast CR and P-sis In your notes, with your lab group: • Make a list or table in which you brainstorm all the similarities and differences between photosynthesis and cellular respiration • Include: • Broad Concepts • Specific Details
AP Bio: Monday, 12.6.10Test on Cellular Energetics • Homework: • Chapter 35 Reading Notes • Do Now: • Look over PS 10 • Get ready for the test • Goals for Today: • Demonstrate knowledge of cell respiration and photosynthesis by answering AP-style multiple choice and open response questions • Agenda: • Quick review of PS 10 • Test