In linear electron flow (unbroken arrows) energy from absorbed photons is used to oxidise water on the luminal face of photosystem II (PS II). … In cyclic electron flow,
energy from absorbed photons causes the oxidation of the
reaction centre (P700) in PS I.
What is a cyclic electron flow?
In cyclic electron flow (CEF),
electrons are recycled around photosystem I
. As a result, a transthylakoid proton gradient (ΔpH) is generated, leading to the production of ATP without concomitant production of NADPH, thus increasing the ATP/NADPH ratio within the chloroplast.
What is the difference between linear and cyclic electron flow quizlet?
Linear electron flow is the electrons that pass through the two photosystems from water to NADP+. Cyclic electron flow are the electrons excited from P700 in PSI are passed from Fd to the cytochrome complex and back to P700.
What is linear electron flow in photosynthesis?
During oxygenic photosynthesis in plants, leaves absorb light energy to drive photosynthetic electron flow in the chloroplasts. In linear electron flow (LEF),
electrons from the splitting of water by the oxygen-evolving complex (OEC) are transferred to NADP
+
, reducing NADP
+
to NADPH
.
What is the difference between cyclic and noncyclic electron flow?
Differentiate Between Cyclic and Noncyclic Photophosphorylation. … In the cyclic photophosphorylation, only ATP is produced, whereas, in the
non-cyclic photophosphorylation both NADPH and ATP are produced
. In cyclic photophosphorylation, the electrons get expelled by photosystem I and they return to the system.
What is the advantage of cyclic flow of electrons?
In higher plants, the generation of proton gradient across the thylakoid membrane (ΔpH) through cyclic electron flow (CEF) has mainly two functions: (1)
to generate ATP and balance the ATP/NADPH energy budget
, and (2) to protect photosystems I and II against photoinhibition.
What is the role of water in noncyclic electron flow?
What is the purpose of water in the noncyclic flow of electrons in photosynthesis?
water splits, thus giving electrons to P680 and having 2 hydrogen ions and one oxygen atom
. This all releases O2.
What is the main function of cyclic photophosphorylation?
Cyclic photophosphorylation
This
transport chain produces a proton-motive force, pumping H
+
ions across the membrane and producing a concentration gradient that can be used to power ATP synthase during chemiosmosis
. This pathway is known as cyclic photophosphorylation, and it produces neither O
2
nor NADPH.
What is the point of cyclic photophosphorylation?
The cyclic photophosphorylation also results in
the formation of ATP molecules
just like in non – cyclic photo phosphorylation. As the electrons move downhill in the electron transport chain, they lose potential energy and ATP molecules are formed in the same way as in mitochondria during respiration.
Is the cyclic electron flow of important in the process?
The reactions involve two types of electron flow in the thylakoid membrane. … The role of cyclic electron transport around PS I is proposed to be essential
for balancing the ATP/NADPH production ratio
and/or for protecting both photosystems from the damage via stromal over-reduction
1
.
What is the purpose of linear electron flow?
In linear electron flow (unbroken arrows)
energy from absorbed photons is used to oxidise water on the luminal face of photosystem II (PS II)
. Electrons generated by this process pass through a series of electron carriers in PS II and then to the oxidized plastoquinones (PQ) that diffuse within the membrane.
What is noncyclic electron flow?
This cooperative process of energy production is called non-cyclic photophosphorylation and
the transfer of electrons from water to NADPH
, known as the Hill Reaction, is noncyclic electron flow. Light is absorbed at PS II, causing the photosystem to grab electrons from water and excite them to a primary acceptor.
What are the products of linear electron flow?
The products of linear electron flow are
ATP and NADPH
.
What happens after non-cyclic electron flow?
In a process called non-cyclic photophosphorylation (the “standard” form of the light-dependent reactions),
electrons are removed from water and passed through PSII and PSI before ending up in NADPH
. This process requires light to be absorbed twice, once in each photosystem, and it makes ATP .
Why is the cyclic pathway so important?
With the cyclic pathway,
plants can save some time and energy
. Since photosystem I is accepting electrons that are returned to it, it is not accepting electrons from the previous electron transport chain. Therefore, the first electron transport chain will be backed up, which means that photolysis will not occur.
Is water split in non-cyclic photophosphorylation?
There is no splitting of water
– the electrons only come from the light harvesting complex. When the electrons reach the end of the chain, they return back to the start of the chain instead of helping to make NADPH as there is no NADP to accept them.
