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Cyclic photophosphorylation takes place in the thylakoid which lacks:
A. Electron transport system
B. Enzyme FNR (ferredoxin NADP reductase)
C. Lumen
D. Photosystem with absorption peak 700nm

Last updated date: 12th Jul 2024
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Hint: Within the chloroplasts of cyanobacteria, thylakoids are membrane-bound compartments. Thylakoids are where photosynthesis' light-dependent reactions take place. A thylakoid membrane surrounds a thylakoid lumen in thylakoids.

Complete answer:
Cyclic photophosphorylation is a photophosphorylation mechanism that causes electrons to pass in a cyclic pattern in order to synthesise ATP molecules. Plant cells simply convert ADP to ATP in this step to provide immediate energy to the cells.
Process of cyclic Phosphorylation:
Photophosphorylation of this kind normally takes place in the thylakoid membrane.
In cyclic electron flow, the electron starts in a pigment complex called photosystem I.
It then moves on to ferredoxin and finally cytochrome b6f after passing through the primary acceptor.
Cytochrome b6f is a cytochrome that is identical to that present in mitochondria.
After that, the electron goes to plastocyanin and then back to chlorophyll.
Throughout this electron transport chain, a proton-motive force is created, which pumps H+ ions across the membrane and creates a concentration gradient that can be used to power ATP synthase during chemiosmosis.
This whole process is referred to as cyclic photophosphorylation. It does not contain O2 or NADPH.
' Electron transport system' does not occur in Cyclic phosphorylation.

So the correct answer is Option A) Electron transport system

The electron transport mechanism takes place in the mitochondrial cristae, which contains a number of cytochromes (enzymes) and coenzymes. These cytochromes and coenzymes act as transport and transfer molecules.