Photosynthesis part deux: The Calvin Cycle Chapter 6-2 pages 117- 120 At right is Melvin Calvin who...
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Transcript of Photosynthesis part deux: The Calvin Cycle Chapter 6-2 pages 117- 120 At right is Melvin Calvin who...
Photosynthesis part deux: The Calvin Cycle
Chapter 6-2 pages 117-120
At right is Melvin Calvin who worked all this outBelow is Calvin who worked out Calvin Ball
Objectives
• Summarize the main events of the calvin cycle
• Describe what happens to the compounds that are made during the calvin cycle
• Distinguish between c3, c4, and CAM plants
• Summarize how the light and dark reactions work together in photosynthesis
• Explain how environmental factors affect photosynthesis
Calvin Cycle
• From photosynthesis we get ATP and NADPH
• Now we’ll use the energy from that to make biomolecules
• The energy from Niagra falls is used to power turbines so we can use electricity to do work
Carbon Fixation
• Carbon fixation is the building of biomolecules from CO2
• 3 steps of the Calvin Cycle1. CO2 diffuses into the stroma
from the surrounding cytoplasm. RuBP is combined with CO2. The new 6 Carbon molecule splits into 2 3 Carbon molecules called PGA
Calvin CycleStep 2
2 PGAs converted to another 3 Carbon molecule PGAL, in a two part process
1. PGA receives a Phosphate from ATP2. NADPH gives its H+
The ADP, NADP+, and Phosphate are reused back in the photosynthesis reaction
Calvin Cycle
Step 3
Some of the PGAL goes back to RuBP so the Cycle can continue
Other PGAL goes elsewhere to make Biomolecules
Balance sheet for Photosynthesis
• Calvin Cycle has to turn 3 times to get a PGAL– That uses 9 ATPs and
6 NADPHs
• Now no glucose has been made yet. Cellular respiration is where Glucose is involved.
The Lakers appreciate the Calvin Cycle, you should to.
Alternative pathways
• C3 Plants only fix carbon through the Calvin Cycle– Most plants are this, trees
for example
• In hot climates plants lose water through open stomata so they need to keep stomata closed
• But stomata are where CO2 & O2 leave and enter the cell
Alternative Pathways
• C4 pathway plants put CO2 into 4 carbon molecules– Corn & Sugar Cane are
examples• CAM pathway plants
have stomata open at night and closed during the day, the opposite as normal– includes Cactus &
Pineapple