Call us toll-free

Quick academic help

Don't let the stress of school get you down! Have your essay written by a professional writer before the deadline arrives.

Calculate the price


275 Words


Basics: Terminal electron acceptor

Same thing that would happen if you clogged a pipe or hose. Once all of the electron acceptors on the transport chain are full, movement stops. The electrons won't be magically absorbed by other parts of the proteins making up the chains, and while there might be errant reactions with other molecules, you'd be lucky to get a whole ATP molecule out in a day - assuming you could magically stay alive.

The point of photosynthesis is to promote electrons to higher energy so that these can be made.

By definition, .

The process of photosynthesis uses raw materials like carbon dioxide, water, and solar energy to produce oxygen and carbohydrates.

The final electron acceptor in light dependent reaction …

Once again, there have to be other ways of doing this, using other molecules as electron acceptors.

In the most familiar examples, green plants use H2O as an electron donor, producing NADH and O2, and mitochondria take electrons from NADH and "run them downstream" to oxygen as the electron acceptor, producing water.

When we're talking about a molecule's fit there are many things to consider. Primarily its electronegativity, as that determines its stability, ability to accept and donate electrons, protons, and its ease of acquisition given plentiful amounts in the environment.

Electron Donors and Acceptors in Anaerobic Respiration

Photosynthesis occurs inside chloroplasts. Chloroplasts contain chlorophyll, a green pigment found inside the thylakoid membranes. These chlorophyll molecules are arranged in groups called photosystems. There are two types of photosystems, Photosystem II and Photosystem I. When a chlorophyll molecule absorbs light, the energy from this light raises an electron within the chlorophyll molecule to a higher energy state. The chlorophyll molecule is then said to be photoactivated. Excited electron anywhere within the photosystem are then passed on from one chlorophyll molecule to the next until they reach a special chlorophyll molecule at the reaction centre of the photosystem. This special chlorophyll molecule then passes on the excited electron to a chain of electron carriers.

This study investigates the role of O2 as an electron acceptor alternative to CO2 in photosynthesis of the common marine angiosperm Zostera marina L. Electron transport rates (ETRs) and non-photochemical quenching (NPQ) of Z. marina were measured under saturating irradiance in synthetic seawater containing 2.2 mM DIC and no DIC with different O2 levels (air-equilibrated levels, 3 % of air equilibrium and restored air-equilibrated levels). Lowering O2 did not affect ETR when DIC was provided, while it caused a decrease in ETR and an increase in NPQ in DIC-free media, indicating that O2 acted as an alternative electron acceptor under low DIC. The ETR and NPQ as a function of irradiance were subsequently assessed in synthetic seawater containing (1) 2.2 mM DIC, air-equilibrated O2; (2) saturating CO2, no O2; and (3) no DIC, air-equilibrated O2. These treatments were combined with glycolaldehyde pre-incubation. Glycolaldehyde caused a marked decrease in ETR in DIC-free medium, indicating significant electron flow supported by photorespiration. Combining glycolaldehyde with O2 depletion completely suppressed ETR suggesting the operation of the Mehler reaction, a possibility supported by the photosynthesis-dependent superoxide production. However, no notable effect of suppressing the Mehler reaction on NPQ was observed. It is concluded that during DIC-limiting conditions, such as those frequently occurring in the habitats of Z. marina, captured light energy exceeds what is utilised for the assimilation of available carbon, and photorespiration is a major alternative electron acceptor, while the contribution of the Mehler reaction is minor.

Order now

    As soon as we have completed your work, it will be proofread and given a thorough scan for plagiarism.


    Our clients' personal information is kept confidential, so rest assured that no one will find out about our cooperation.


    We write everything from scratch. You'll be sure to receive a plagiarism-free paper every time you place an order.


    We will complete your paper on time, giving you total peace of mind with every assignment you entrust us with.


    Want something changed in your paper? Request as many revisions as you want until you're completely satisfied with the outcome.

  • 24/7 SUPPORT

    We're always here to help you solve any possible issue. Feel free to give us a call or write a message in chat.

Order now

The role of O2 as an electron acceptor alternative to …

Oxygen is the so-called terminal electron acceptor of the electron transport chain in eukaryotes. You can see "reduction potential" as a kind of stored "energy" which molecules have, similar to the power stored in batteries (very similar actually). To make this text a bit shorter I'll call it "RP" from now on.

Terminal electron acceptor - Biology-Online Dictionary

The effect of iron deficiency on photosynthetic electron transport in Photosystem II (PS II) was studied in leaves and thylakoid membranes of lettuce (Lactuca sativa, Romaine variety) plants. PS II electron transport was characterized by oxygen evolution and chlorophyll fluorescence parameters. Iron deficiency in the culture medium was shown to affect water oxidation and the advancement of the S-states. A decrease of maximal quantum yield of PS II and an increase of fluorescence intensity at step J and I of OJIP kinetics were also observed. Thermoluminescence measurements revealed that charge recombination between the quinone acceptor of PS II, QB, and the S2 state of the Mn-cluster was strongly perturbed. Also the dark decay of Chl fluorescence after a single turnover white flash was greatly retarded indicating a slower rate of QA reoxidation.


Carbon? Nope, as an ion it's dangerously reactive, and as anything else it's too stable. Plus, we're carbon-based! If we used carbon as the terminal acceptor then the proteins handling the electrons would have to be even more exotic and filled with other elements to prevent them accidentally gobbling up the electron and becoming useless.

The Oxygen Evolving System of Photosynthesis

Sulfur? Not electronegative enough for human purposes, unfortunately. It wouldn't act as a terminal acceptor unless our bodies seriously oxidized it; and any oxidized molecules floating around would be more dangerous than molecular oxygen floating around. Plus most sulfur is bound to minerals as well - not abundant unless you're in the ocean.

What is the ultimate electron acceptor in photosynthesis

To understand photosynthesis and respiration, you have to see the relationship between moving electrons through a potential difference (volts) and a free energy change (kilocalories or kiloJoules).

Order now
  • You submit your order instructions

  • We assign an appropriate expert

  • The expert takes care of your task

  • We send it to you upon completion

Order now
  • 37 684

    Delivered orders

  • 763

    Professional writers

  • 311

    Writers online

  • 4.8/5

    Average quality score

Order now
  • Kim

    "I have always been impressed by the quick turnaround and your thoroughness. Easily the most professional essay writing service on the web."

  • Paul

    "Your assistance and the first class service is much appreciated. My essay reads so well and without your help I'm sure I would have been marked down again on grammar and syntax."

  • Ellen

    "Thanks again for your excellent work with my assignments. No doubts you're true experts at what you do and very approachable."

  • Joyce

    "Very professional, cheap and friendly service. Thanks for writing two important essays for me, I wouldn't have written it myself because of the tight deadline."

  • Albert

    "Thanks for your cautious eye, attention to detail and overall superb service. Thanks to you, now I am confident that I can submit my term paper on time."

  • Mary

    "Thank you for the GREAT work you have done. Just wanted to tell that I'm very happy with my essay and will get back with more assignments soon."

Ready to tackle your homework?

Place an order