→What is cyclic phosphorylation in biology?
Cyclic phosphorylation is a process in cellular respiration in which a molecule of adenosine diphosphate (ADP) is converted into adenosine triphosphate (ATP) through a series of chemical reactions in a cyclic manner.
→How does cyclic phosphorylation work?
Cyclic phosphorylation involves the movement of electrons along the electron transport chain in the mitochondria, which generates a proton gradient that drives the production of ATP through the action of the ATP synthase enzyme.
→What is non-cyclic phosphorylation in biology?
Non-cyclic phosphorylation, also known as linear or oxidative phosphorylation, is the process of generating ATP through the transfer of electrons from NADH and FADH2 to oxygen in the mitochondria. This process also generates a proton gradient which drives ATP production.
→What happens in non-cyclic phosphorylation?
In non-cyclic photophosphorylation, both photosystem I (PSI) and photosystem II (PSII) are involved in a linear electron flow that results in the production of ATP and NADPH. The process can be summarized in the following steps:
Light energy is absorbed by the pigments in PSII, exciting electrons to a higher energy level. These high-energy electrons are then passed through an electron transport chain (ETC) to PSI, releasing energy that is used to generate a proton gradient across the thylakoid membrane.
Water molecules are split by PSII, releasing electrons, protons (H+), and oxygen gas. The electrons from water replace the high-energy electrons lost by PSII and are passed through the ETC to PSI.
The high-energy electrons from PSI are used to reduce NADP+ to NADPH, which is used as a reducing agent in the light-independent reactions of photosynthesis.
The proton gradient generated by the ETC is used by ATP synthase to generate ATP from ADP and inorganic phosphate.
Overall, non-cyclic photophosphorylation produces both ATP and NADPH, which are used in the Calvin cycle to convert CO2 into organic compounds such as glucose.
→What is the difference between cyclic and non-cyclic photophosphorylation in A-level Biology?
In A-level Biology, photophosphorylation is the process by which light energy is used to produce ATP, the energy currency of cells. There are two types of photophosphorylation that occur during photosynthesis in plants: cyclic and non-cyclic photophosphorylation.
Non-cyclic photophosphorylation involves both photosystem I (PSI) and photosystem II (PSII) in a linear electron flow that results in the production of ATP and NADPH. In this process, water is split by PSII, releasing oxygen and hydrogen ions. Electrons are transferred from PSII to PSI via an electron transport chain, which generates a proton gradient across the thylakoid membrane. This gradient is used to drive the synthesis of ATP by ATP synthase, while NADP+ is reduced to NADPH by electrons from PSI.
In cyclic photophosphorylation, only PSI is involved in a circular electron flow that generates ATP but not NADPH. Electrons from PSI are cycled back to PSI via an electron transport chain, which generates a proton gradient that is used to produce ATP by ATP synthase. Since no electrons are transferred to NADP+, no NADPH is produced during cyclic photophosphorylation.
Overall, the main difference between cyclic and non-cyclic photophosphorylation is the involvement of both PSII and PSI in non-cyclic photophosphorylation, which results in the production of both ATP and NADPH, whereas cyclic photophosphorylation involves only PSI and produces only ATP.
Source: studymind.co.uk/notes/cyclic-....
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