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Energy Capturing Pathways ( Photosynthesis ). I. Introduction. A. History. 1. VanHelmont ,1630, showed plants need. Water. 2. Priestly , 1772, showed plants need. Gas ( phlogiston ). 3. Ingenhaus , 1779, showed plants need. Sunlight. 4. DeSaussure , 1804, showed.
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Energy Capturing Pathways (Photosynthesis) I. Introduction A. History
1. VanHelmont,1630, showed plants need Water 2. Priestly, 1772, showed plants need Gas (phlogiston) 3. Ingenhaus, 1779, showed plants need Sunlight 4. DeSaussure, 1804, showed organized all the pieces the hydrogen in the glucose comes from splittingwater 5. Van Neil, 1930, showed
Photosynthesis Overview Figure 6.3
Autotrophs (self feeders) are organisms that can fix energy into carbon molecules. Page 88 Figure 6.1
B. Background Information 1. Chloroplast Structure
Photosynthetic Structures Figure 6.2 Figure 6.2
Light Properties Figure 6.4
Pigments Magnesium Chlorophylls are primary and reflect greens. Xanthophylls are secondary and reflect reds. Carotenoids are secondary and reflect oranges and protect chlorophylls. Figure 6.5
C. Light Dependent Reactions 1. Where
The light dependent reactions occur via chlorophyll pigments in the thylakoid membrane of chloroplasts. Why is this solution red?
Light Dependent Reaction Steps Figure 6.6
Making ATP & NADPH + H+ with sunlight Figure 6.7
Light Dependent Reaction Steps 1.Light excites electrons of magnesium of the chlorophyll molecules of photo-system II and I. 2. Electrons from II are passed through an ETC to make ATP, while electrons from I are passed through an ETC to make NADPH + H+. 3. Electrons from II are used to backfill I chlorophyll that lost electrons to NADPH + H+. 4.Water is split by II to fill electrons lost to I by stealing electrons from hydrogen.
The ATPandNADPH + H+. sent to chloroplast stromaand are used to energize CO2(via ATP) &add hydrogen(via NADPH + H+.) The O2to the stomata to be expelled ormitochondria Do plants need to keep expelling O2 for their benefit? Or yours?
D. Light Independent Reactions 1. Where
The eight step process (Calvin cycle, the light independent reactions, or the DARK reactions) is in the chloroplast’s stroma Figure 6.3
Light Independent Reaction Steps Figure 6.8
1. Rubisco attaches 3CO2 to RuBP 2. Requires 6ATP and 6NADPH + H+ to make 6G3P 3. Separate 1G3P and hold in reserve 4. Rearrange other 5G3P back into RuBP requiring 3ATP 5. Repeat as long as you have enough ???? 1Glucose requires 18ATP + 12NADPH + H+.
3. Outcomes What to do with the glucose?
E. Alternative Strategies 1. Photorespiration
Rubiscocan also bind toO2 (Photorespiration) C3 plants go senescent rice, wheat, some grasses, and soybean Figure 6.10
C4 plants turn CO2into acid molecules then break up to giveCO2to Rubisco sugarcane, corn, and other grasses Figure 6.12
CAM plants completely separate light from dark reactions cactus, pineapples, and succulents Figure 6.13
Comparing C3with C4 and CAM leave structures. Figure 6.11