Question

7) _photosynthesis___ is the process that involves rubisco fixing oxygen instead of carbon dioxide, resulting in a depletion of organic material in the Calvin cycle and an overall reduction in photosynthetic activity.

8) Noncyclic electron flow in the photosystems produces ATP

Answer 1

8. Photorespiration is the process that involves rubisco fixing oxygen instead of carbon dioxide, resulting in a depletion of organic material in the Calvin cycle and an overall reduction in photosynthetic activity.

• RuBisCO is a key enzyme onvolved in phiotosynthesis.
• But RuBisCO also uses oxygen as the substrate and this leads to the photorespiratory pathways.
• In photorespiration the enzyme fixes oxygen istead of carbondioxide with the expense of the energy produced by photosynthesis.
• The photorespiration is considered as a wasteful process because
  • the 3-phosphoglycerate is created at a reduced rate
  • Photorespiration requires higher metabolic cost
  • Leads to the loss of the fixed carbon

9.True. The noncyclic electron flow in the photosystems can produce ATP.This process is called non-cyclic photophosphorylation.In this process the ATP is synthesised using the energy derived from the excited electrons provided by photosystem II.