Cyclic phosphorylation

photosynthesis

1. Welcome to presentation

2. Topic: cyclic phosphorylation

3. Presented to: sir faisal iqbal presented by: farhana shiekh ( bs-bot-f17-r03)

4. contents: Short introduction to photo phosphorylation Definition of cyclic photophosphorylation. Mechanism Steps Flowsheet

5. Phtophosphoryltion :

6. Photophosphorylation: In the process of photosynthesis, the phosphorylation of ADP to ATP using the energy of sunlight is called photophosphorylation . TYPES OF PHOTOPHOSPHORYLATION There are two types of photophosphorylation 1.Cyclic photophosphorylation 2.Non-cyclic photophosphorylation

7. Cyclic photophosphorylation : “The returning back of the same excited electron to excited chlorophyll by producing a molecule of ATP is called cyclic phosphorylation”.

8. Mechanism : In bacterial photosynthesis, a single photosystem is involved. When an electron is energized by absorption of light, it is ejected from the photosystem reaction centre . The electron then passes down through an electron transport system, and finally to the reaction centre . The energy released during this electron transport is used to produce ATP. Since the excited electron returns to the reaction centre , this mechanism for making ATP is called cyclic photophosphorylation .

9. steps: First of all P700 of the photosystem 1 absorb light.this light drives electron from P700 to primary electron acceptor.it produce electron hole in the chlorophyll. The primary acceptor of electron of PS1 transfer electron to Fe-S protein. Fe-S protein transfer electron to ferrodoxin . Electron transfer from ferodoxin to cytochrome complex.

10. Conti……………… Finally the cytochrome complex return theses electron to excited chlorophyll of P700. A molecule of ATP is produced during this transfer of electron through ETC by chemiosmosis. The NADH is not produce and oxygen is not released.

11. Thank you