4/27 Daily Catalyst Photosynthesis Review 1. Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis? A) The light-dependent reactions occur only during the day; the light-independent reactions occur only during the night. B) The light-dependent reactions occur in the cytoplasm; the light-independent reactions occur in chloroplasts. C) The light-dependent reactions produce ATP and NADPH; the light-independent reactions use stored energy in ATP and NADPH. D) The light-dependent reactions utilize CO2 and H2O; the light-independent reactions produce CO2 and H2O. 2. Photosynthesis is a process used by plants and other organisms to convert the light energy captured from the sun into chemical energy that can be used to fuel the organism's activities. All of the following could reduce the yield of photosynthetic products EXCEPT A) Increased photorespiration B) Fewer Calvin Cycle enzymes C) Reduced carbon dioxide concentrations in the air spaces of the leaf D) Increased frequency of stomata openings

Math review-Mrs. Ireland 4/21 Ecology Erica 4/22 Evolution John Monday Tuesday Wednesday Thursday Friday 4/20 Math review-Mrs. Ireland 4/21 Ecology Erica 4/22 Evolution John Daquine 4/23 Transport Daniel 4/24 Cells-organelles Tiana Tiffany 4/27 Photosynthesis Quinshelle 4/28 Cellular respiration 4/29 DNA/RNA Bristin 4/30 Genetics/pedigree/punnett squares Tiffany Kiandria 5/1 Mitosis/meiosis Kordell 5/4 Rep/trans/transcript James, Joe, Paul 5/5 5/6 5/7 5/8 5/11 AP Test Day! 5/12 5/13 Pig Dissection 5/14 5/15 Dissection Presentation Class review questions Individual review questions HW or WS acceptable!

ATP H+ H+ H+ H+ H+ H+ ADP H+ P thylakoid membrane thylakoid space stroma ATP synthase e- NADPH NADP+ e- Photosystem I (P700) Photosystem II (P680) 5000 e- 4999 e- 5000 e- 5000 e- 5000 e- 4999 e- This “animation” walks through the steps of noncyclic electron flow, as outlined on the previous 3 slides. The “5000 e-” is meant for illustrative purposes only; no matter how many electrons were contained in photosystems II and I, if there was no way to replace those electrons, eventually the number of electrons would be 0. If that were to occur, there would no electrons to be excited by light, and the light reactions would grind to a halt. The electron that was “excited away” from photosystem I is replaced by the electron that was “excited away” from photosystem II; photosystem II’s lost electron is replaced through photolysis – the splitting of water – which releases ½ a molecule of O2 as a byproduct. This is where the oxygen comes from that is produced during photosynthesis, and is why autotrophs need water to perform photosynthesis! The oxygen is released through the stomata. The electron that was excited away from Photosystem I ends up reducing [adding an electron to] NADP+ to form NADPH, an important electron carrier that is needed in the Calvin Cycle. Make sure to point out to students the coupled reactions that occur; as the electron travels down the electron transport chain, its “lost energy” is used to pump protons from the stroma to the thylakoid space to build a concentration gradient. Then, as those protons diffuse back across the thylakoid membrane through ATP synthase to achieve equilibrium, they cause ATP synthase to spin (like a turbine), which forces ADP and the phosphate group together, forming ATP. Don’t forget to point out that the membrane is key here! If there was no thylakoid membrane (or if its integrity was disrupted and therefore “leaky”), it would be impossible to build this concentration gradient – not to mention that the cytochromes, photosystems, and ATP synthase would not exist/be functional! Make sure to make the connection with “osmosis” when discussing “chemiosmosis;” for students who understand the idea of the movement of molecules from an area of high concentration to an area of low concentration (as in osmosis), discuss the idea that this is essentially the same process, just with protons (H+) instead of water molecules. H+ H+ H H H+ O H+ H+ H+ H+ e- H+ O H+ (2 H+ & ½ O2)

Phase 2: The Calvin Cycle CO2 Rubisco ATP RuBP NADPH - This simple schematic diagram gives a basic overview of what occurs during the Calvin Cycle. Carbon dioxide enters the cycle from the atmosphere and is joined to RuBP by Rubisco. NADPH and ATP are used to “turn” the cycle, and organic compounds (such as G3P/PGAL) are produced. NADP+ ADP P ORGANIC COMPOUND

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