Cyclic photophosphorylation

• Cyclic photophosphorylation involves only photosystem I.
• Light is absorbed by photosystem I and passed to the primary pigment where an electron is excited to a higher energy level.
• The excited electron passes down a series of electron acceptors until finally returning back to the reaction center of photosystem I.
• As the electron passes down a chain of electron carriers energy is released and used to generate ATP by chemiosmosis.
• The end products of cyclic photophosphorylation include ATP only.