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THE CALVIN CYCLE. Or LIGHT INDEPENDENT REACTION OR DARK REACTION. What is the Calvin Cycle?. It is the 2 nd phase of photosynthesis that through a series of reactions uses CO2 to form carbohydrates. Where does the Calvin Cycle take Place?. IN THE STROMA.
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THE CALVIN CYCLE Or LIGHT INDEPENDENT REACTION OR DARK REACTION
What is the Calvin Cycle? • It is the 2nd phase of photosynthesis that through a series of reactions uses CO2 to form carbohydrates
Where does the Calvin Cycle take Place? • IN THE STROMA
Step 1 of the Calvin CycleCARBON FIXATION • 1 carbon atom from CO2 is added to a 5 carbon sugar(RuBP) or ribulose biphosphate • C-C-C-C-C-C • RuBisCo or ribulose biphosphate carboxylase/oxygenase is an enzyme that is used to catalize the 1st step in carbon fixation. Some consider most important protein found in life
STEP 2 • PGA formation or Phosphoglyceric Acid • 6 carbon sugar formed in step one is broken down to from two molecules of PGA. • C-C-C(PGA 1) • C-C-C(PGA 2)
STEP 3 • PGA through a series of reactions involving ATP (adenosine triphosphate) and NADPH (nicodinamide adenine dinucleotide phosphate) converts a molecule of PGA into Phosophoglyceraldehyde or PGAL
STEP 4 • After several rounds of the Calvin cycle, 2 molecules of PGAL leave cycle to form glucose • C-C-C-C-C-C
STEP 5REFORM RuDP • ATP (adensine triphosphate) and PGAL put back the Ru BP • Some PGAL from step 3 and 4 re-form the 5 carbon sugar with help of ATP
IT TAKES 6 ROUNDS OF CALVIN CYCLE TO PRODUCE1 GLUCOSE MOLECULE
SUMMARY OF PHOTOSYNTHEIS • Light dependent reactions take light energy from sun and convert to chemical energy • Light independent reactions: produce glucose
Other Pathways to Fix Carbon • C3 Plants: Plants that fix carbon through Calvin cycle. Use stomata: pores in leaves that allows CO2 to enter and O2 to leave. Open during day • C4 Plants: Use alternate pathways to fix carbon Ex. Corn, sugar can, close during day CAM Plants: Plants open stomata at night instead of day. Cactus and pineapples
Factors that affect Photosyntheis • Light intensity increase phot. • Carbon dioxide content increase phot. • Temperature (to a point) increase photo
o.k. NOW YOU HAVE TO LEARN IT!!!