The rate of cellular respiration is regulated by its major product, ATP, via feedback inhibition. I don't quite understand why oxygen is essential in this process. In organisms that perform cellular respiration, glycolysis is the first stage of this process. It would increase ATP production, but could also cause dangerously high body temperature, It would decrease ATP production, but could also cause dangerously high body temperature, It would decrease ATP production, but could also cause dangerously low body temperature, It would increase ATP production, but could also cause dangerously low body temperature, Posted 7 years ago. Drag each compound to the appropriate bin. Electron transport and oxidative phosphorylation is the third and final step in aerobic cellular respiration. d. NADH L.B. Oxidative phosphorylation is made up of two closely connected components: the electron transport chain and chemiosmosis. The free energy from the electron transfer causes 4 protons to move into the mitochondrial matrix. What are the inputs and outputs of pyruvate oxidation? The electrons are transferred to molecular oxygen from an energy precursor that is produced in a citric acid cycle through the use of enzymes. citation tool such as, Authors: Samantha Fowler, Rebecca Roush, James Wise. FADH2 in the matrix deposits electrons at Complex II, turning into FAD and releasing 2 H+. _________ is a nonprotein organic electron carrier within the electron transport chain. Cellular respiration is one of the most elegant, majestic, and fascinating metabolic pathways on earth. What does this mean for your table on the 'breakdown of one molecule of glucose'? J.B. is 31 years old and a dispatcher with a local oil and gas company. The roles of these complexes, respectively, are to capture light energy, create a proton gradient from electron movement, capture light energy (again), and use proton gradient energy from the overall process to synthesize ATP. Think about whether any carbon compounds play a role in oxidative phosphorylation. If you block the exit, the flow through the entire pipeline stalls and nothing moves. The first is known as PQA. In eukaryotic cells, pyruvate is imported into the mitochondrial matrix for pyruvate oxidation. These metabolic processes are regulated by various . The output involved in glycolysis is four ATP, two NADH (nicotinamide adenine dinucleotide hydrogen) and two pyruvate molecules. Direct link to ILoveToLearn's post Hello Breanna! The excited electron from PS II must be passed to another carrier very quickly, lest it decay back to its original state. Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions? When protons flow through ATP synthase, they cause it to turn (much as water turns a water wheel), and its motion catalyzes the conversion of ADP and Pi to ATP. The eight steps of the cycle are a series of chemical reactions that produces two carbon dioxide molecules, one ATP molecule (or an equivalent), and reduced forms (NADH and FADH2) of NAD+ and FAD+, important coenzymes in the cell. So. That's my guess and it would probably be wrong. 3. Direct link to Ivana - Science trainee's post `C6H12O6 + 6O2 6CO2 + 6, Posted 5 years ago. The high-energy electrons from NADH will be used later to generate ATP. The new Campbell Biology textbook updated the ATP yield totals to be 26-28 (instead of 30-32). The electron transport chain is a series of protein complexes and electron carrier molecules found within the mitochondrial membrane in eukaryotic cells. If oxygen isnt there to accept electrons (for instance, because a person is not breathing in enough oxygen), the electron transport chain will stop running, and ATP will no longer be produced by chemiosmosis. Cellular respiration is oxidative metabolism of glucose which takes place in mitochondria and in the cell. NADH (nicotinamide adenine dinucleotide hydrogen). Transcribed image text: 23) Describe the 4 main steps in cellular respiration and identify the key inputs and outputs of I) glycolysis, 11) pyruvate oxidation, III) the citric acid cycle, and IV) oxidative phosphorylation 24) Associate the various stages of cellular respiration to structural features of the mitochondrion and how selective As electrons move down the chain, energy is released and used to pump protons out of the matrix and into the intermembrane space, forming a gradient. Harvesting the energy of light begins in PS II with the absorption of a photon of light at a reaction center. Oxidative phosphorylation. The electrons from Complexes I and II are passed to the small mobile carrier Q. Q transports the electrons to Complex III, which then passes them to Cytochrome C. Cytochrome C passes the electrons to Complex IV, which then passes them to oxygen in the matrix, forming water. Creative Commons Attribution License At the end of the electron transport chain, oxygen accepts electrons and takes up protons to form water. As electrons travel towards NADP+, they generate a proton gradient across the thylakoid membrane, which is used to drive synthesis of ATP. Labels may be used more than once. NADH and FADH2 made in the citric acid cycle (in the mitochondrial matrix) deposit their electrons into the electron transport chain at complexes I and II, respectively. then you must include on every physical page the following attribution: If you are redistributing all or part of this book in a digital format, Direct link to tyersome's post Remember that all aqueous, Posted 6 years ago. Suggest Corrections 1 Similar questions Q. The thylakoid membrane does its magic using four major protein complexes. Direct link to Herukm18's post What does substrate level, Posted 5 years ago. I get that oxygen serves as an electron acceptor at the end of the electron transport chain, but why is having this electron acceptor so important? Failure in oxidative phosphorylation causes the deregulation of ATP-synthase activities in mitochondria and contributes to the elevation of oxidative stress and cell . Net Input: NADH, ADP, O Net Output: NAD, ATP, CO and Water Not Input or Output: Pyruvate, Glucose, Acetyl CoA, Coenzyme A and CO. There are four complexes composed of proteins, labeled I through IV in Figure 4.15c, and the aggregation of these four complexes, together with associated mobile, accessory electron carriers, is called the electron transport chain. The outputs (products) are carbon dioxide, NADH, and acetyl CoA. In anaerobic states, pyruvic acid converts to lactic acid, and the net production of 2 ATP molecules occurs. If the compound is not involved in glycolysis, drag it to the "not input or output" bin. In chemiosmosis, the energy stored in the gradient is used to make ATP. This cycle is catalyzed by several enzymes and is named in honor of the British scientist Hans Krebs who identified the series of steps involved in the citric acid cycle. Where does it occur? Electron transport is a series of chemical reactions that resembles a bucket brigade in that electrons are passed rapidly from one component to the next, to the endpoint of the chain where oxygen is the final electron acceptor and water is produced. What affect would cyanide have on ATP synthesis? What are the inputs and outputs of pyruvate oxidation? From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of acetyl CoA formation. Source: BiochemFFA_5_3.pdf. Describe the relationships of glycolysis, the citric acid cycle, and oxidative phosphorylation in terms of their inputs and outputs. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. [1] Defects in oxidative phosphorylation, mitochondrial mechanisms, and calcium signalling are interconnected in a cascade sequence and ultimately lead to neurodegeneration in AD. The electron transport chain and the production of ATP through chemiosmosis are collectively called oxidative phosphorylation. Direct link to Peony's post well, seems like scientis, Posted 6 years ago. What is the first thing to do if a pt is in ventricular tachycardia? Photons from the sun interact with chlorophyll molecules in reaction centers in the chloroplasts (Figures and ) of plants or membranes of photosynthetic bacteria. Photosynthesis is an energy capture process found in plants and other organisms to harvest light energy and convert it into chemical energy. Direct link to Medha Nagasubramanian's post Is oxidative phosphorylat, Posted 3 years ago. For instance, hibernating mammals (such as bears) have specialized cells known as brown fat cells. Why would ATP not be able to be produced without this acceptor (oxygen)? In a broad overview, it always starts with energy capture from light by protein complexes, containing chlorophyll pigments, called reaction centers. As electrons move energetically downhill, the complexes capture the released energy and use it to pump H, Like many other ions, protons can't pass directly through the phospholipid bilayer of the membrane because its core is too hydrophobic. A primary difference is the ultimate source of the energy for ATP synthesis. It does this, giving its electron within picoseconds to pheophytin (Figure \(\PageIndex{8}\)). Simple diagram of the electron transport chain. Oxygen is what allows the chain to continue and keep producing ATP. Step 3. In biological systems, this reaction is vital for the cellular storage and transfer of free energy using energy carrier molecules. Fermentation results in a net production of 2 ATP per glucose molecule. The electron transport chain is present in multiple copies in the inner mitochondrial membrane of eukaryotes and in the plasma membrane of prokaryotes. The stages of cellular respiration include glycolysis, pyruvate oxidation, the citric acid or Krebs cycle, and oxidative phosphorylation. If a compound is not involved in oxidative phosphorylation, drag it to the "not input or output" bin. Direct link to Abdul Mannan's post How much electron NADH & . Oxidative phosphorylation is the process by which the synthesization of ATP takes place. Another source of variance stems from the shuttle of electrons across the mitochondrial membrane. How is ATP produced in cellular respiration? D) 5 C Like the questions above. This page titled 5.3: Energy - Photophosphorylation is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Kevin Ahern, Indira Rajagopal, & Taralyn Tan. The mammalian circadian system is a hierarchically organized system, which controls a 24-h periodicity in a wide variety of body and brain functions and physiological processes. Hydrogen ions diffuse through the inner membrane through an integral membrane protein called ATP synthase (Figure 4.15b). But technically there should be net two protons left in cytosol and that's where I am puzzled. Direct link to tmytltr's post if glycolysis requires AT, Posted 4 years ago. It has two important functions: Complexes I, III, and IV of the electron transport chain are proton pumps. Correct: Sort the labels into the correct bin according to the effect that gramicidin would have on each process. are not subject to the Creative Commons license and may not be reproduced without the prior and express written Within the context of systems theory, the inputs are what are put into a system and the outputs are the results obtained after running an entire process or just a small part of . 6. Instead, it must hand its electrons off to a molecular shuttle system that delivers them, through a series of steps, to the electron transport chain. Oxidative phosphorylation is powered by the movement of electrons through the electron transport chain, a series of proteins embedded in the inner membrane of the mitochondrion. Each turn of the cycle forms three high-energy NADH molecules and one high-energy FADH2 molecule. 2GPs are converted into two PYRUVATE molecules releasing energy (2 x ATP). Thus at the end of GLYCOLYSIS, one glucose mocule has generated 2 pyruvate molecules (to the LINK REACTION) 2 ATP molecules (2 input, 4 output) 2 red NAD molecules (to OXIDATIVE PHOSPHORYLATION) NO CO 2 is produced by glycolysis The LINK REACTION Overview __________ is the compound that functions as the electron acceptor in glycolysis. Cyanide, and that weight control pill all cause the normal respiration to function abnormally. In this article, we'll examine oxidative phosphorylation in depth, seeing how it provides most of the ready chemical energy (ATP) used by the cells in your body. In poorly oxygenated tissue, glycolysis produces 2 ATP by shunting pyruvate away from mitochondria and through the lactate dehydrogenase reaction. Jan 9, 2023 OpenStax. After oxidative phosphorylation, the ATP created is in the mitochondrial matrix, right? When protons flow back down their concentration gradient (from the intermembrane space to the matrix), their only route is through ATP synthase, an enzyme embedded in the inner mitochondrial membrane. However, the oxidation of the remaining two carbon atomsin acetateto CO2 requires a complex, eight-step pathwaythe citric acid cycle. Oxidative Phosphorylation: Oxidative phosphorylation is the final metabolic step of cellular respiration that is used to produce. You, like many other organisms, need oxygen to live. Direct link to Eva Klein's post I have a question Whic, Posted 6 years ago. Wikipedia. consent of Rice University. As you know if youve ever tried to hold your breath for too long, lack of oxygen can make you feel dizzy or even black out, and prolonged lack of oxygen can even cause death. Direct link to Nick Townsend's post Just like the cell membra, Posted 7 years ago. With absorption of a photon of light by PS I, a process begins, that is similar to the process in PS II. Approximately how much more free energy is supplied to the electron transport chain by NADH than by FADH2? The answer is the captured energy of the photons from the sun (Figure 5.59), which elevates electrons to an energy where they move downhill to their NADPH destination in a Z-shaped scheme. In the last stage of cellular respiration, oxidative phosphorylation, all of the reduced electron carriers produced in the previous stages are oxidized by oxygen via the electron transport chain. The electrons have made their way from water to NADPH via carriers in the thylakoid membrane and their movement has released sufficient energy to make ATP. At this point, the light cycle is complete - water has been oxidized, ATP has been created, and NADPH has been made. is 29 years old and a self-employed photographer. Glycolysis is an ancient metabolic pathway, meaning that it evolved long ago, and it is found in the great majority of organisms alive today ^ {2,3} 2,3. Direct link to Chaarvee Gulia's post I don't quite understand , Posted 5 years ago. Note that two types of electron carriers are involved. This will be discussed elsewhere in the section on metabolism (HERE). [(Cl3CCO)2O]\left[ \left( \mathrm { Cl } _ { 3 } \mathrm { CCO } \right) _ { 2 } \mathrm { O } \right] Function. In glycolysis, the carbon-containing compound that functions as the electron donor is __________. It is easier to remove electrons and produce CO2 from compounds with three or more carbon atoms than from a two-carbon compound such as acetyl CoA. Oxidative phosphorylation is the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH 2 to O 2 by a series of electron carriers. Overview of oxidative phosphorylation. NADH and FADH2 are both electron carriers that donate their electrons to the electron transport chain. The protons flow back into the matrix through an enzyme called ATP synthase, making ATP. Let's start by looking at cellular respiration at a high level, walking through the four major stages and tracing how they connect up to one another. In mitochondria, pyruvate will be transformed into a two-carbon acetyl group (by removing a molecule of carbon dioxide) that will be picked up by a carrier compound called coenzyme A (CoA), which is made from vitamin B5. To summarize the light dependent reactions, let ' s look at the inputs and outputs: INPUTS: OUTPUTS: Light Energy: ATP: Water (H 2 O) NADPH : Oxygen Molecules (O 2) Study how the electrons are made available and what happens to them. Direct link to sophieciurlik's post When it states in "4. Thus, electrons are picked up on the inside of the mitochondria by either NAD+ or FAD+. 1999-2023, Rice University. It may also be vestigial; we may simply be in the process of evolving towards use only of higher-energy NADH and this is the last enzyme that has . and you must attribute OpenStax. Anaerobic glycolysis serves as a means of energy production in cells that cannot produce adequate energy through oxidative phosphorylation. Direct link to DonaShae's post Cellular Respiration happ, Posted 6 years ago. Phosphate located in the matrix is imported via the proton gradient, which is used to create more ATP. This is the primary step in cellular respiration. However, most current sources estimate that the maximum ATP yield for a molecule of glucose is around 30-32 ATP, Where does the figure of 30-32 ATP come from? Describe the relationships of glycolysis, the citric acid cycle, and oxidative phosphorylation in terms of their inputs and outputs. Phosphorylation Definition. A single glucose molecule consumes 2 ATP molecules and produces 4 ATP, 2 NADH, and two pyruvates. Where do the hydrogens go? L.B. The chloroplasts are where the energy of light is captured, electrons are stripped from water, oxygen is liberated, electron transport occurs, NADPH is formed, and ATP is generated. The coupling works in both directions, as indicated by the arrows in the diagram below. This photochemical energy is stored ultimately in carbohydrates which are made using ATP (from the energy harvesting), carbon dioxide and water. The similarities of photophosphorylation to oxidative phosphorylation include: In some ways, the movement of electrons in chloroplasts during photosynthesis is opposite that of electron transport in mitochondria. These include Photosystem II (PS II), Cytochrome b6f complex (Cb6f), Photosystem I (PS I), and ATP synthase. Acetyl CoA and Oxaloacetic Acid combine to form a six-carbon molecule called Citric Acid (Citrate). It consists of two stepsthe electron transport chain and chemiosmosis which create and use an electrochemical gradient to produce ATP from ADP. If oxygen is not present, this transfer does not occur. Pyruvate: Pyruvate is a molecule obtained as the main end-product of glycolysis performed in the cellular respiration mechanism. Instead of electrons going through ferredoxin to form NADPH, they instead take a backwards path through the the proton-pumping b6f complex. When a compound accepts (gains) electrons, that compound becomes ________. Last, it should be noted that photosynthesis actually has two phases, referred to as the light cycle (described above) and the dark cycle, which is a set of chemical reactions that captures CO2 from the atmosphere and fixes it, ultimately into glucose. The oxygen liberated in the process is a necessary for respiration of all aerobic life forms on Earth. Direct link to Ellie Bartle's post Substrate level is the 'd, Posted 5 years ago. All the components of the chain are embedded in or attached to the inner mitochondrial membrane. The mitochondria would be unable to generate new ATP in this way, and the cell would ultimately die from lack of energy. The steps above are carried out by a large enzyme complex called the pyruvate dehydrogenase complex, which consists of three interconnected enzymes and includes over 60 subunits. If NADH becomes NAD+, it releases H+ and if FADH2 becomes FAD and would release 2H+. The electron transport chain forms a proton gradient across the inner mitochondrial membrane, which drives the synthesis of ATP via chemiosmosis. If oxygen is available, aerobic respiration will go forward. Oxi, Posted a year ago. The coupled stages of cellular respiration Mitochondrial diseases are genetic disorders of metabolism. Drag the labels from the left (which represent numbers of carbon atoms) onto the diagram to identify the number of carbon atoms in each intermediate in acetyl CoA formation and the citric acid cycle. The acetyl CoA combines with a four-carbon molecule and goes through a cycle of reactions, ultimately regenerating the four-carbon starting molecule. The electron transport chain (Figure 4.19 a) is the last component of aerobic respiration and is the only part of metabolism that uses atmospheric oxygen. PQA hands the electron off to a second plastoquinone (PQB), which waits for a second electron and collects two protons to become PQH2, also known as plastoquinol (Figure \(\PageIndex{9}\)). PQH2 passes these to the Cytochrome b6f complex (Cb6f) which uses passage of electrons through it to pump protons into the thylakoid space. Fewer ATP molecules are generated when FAD+ acts as a carrier. The turning of the parts of this molecular machine regenerate ATP from ADP. Hm. A cell stays small to allow easier transport of molecules and charged particles from organelles. Direct link to eurstin's post In the Citric Acid Cycle , Posted 7 years ago. It was used until 1938 as a weight-loss drug. What would happen to the cell's rate of glucose utilization? What Are the net inputs and net outputs of oxidative phosphorylation? In aerobic respiration, 38 ATP molecules are formed per glucose molecule. Any disruption of this balance leads to oxidative stress, which is a key pathogenic factor in several ocular diseases. Direct link to Satwik Pasani's post It is sort of like a pipe, Posted 5 years ago. a. pyruvate (Assume that gramicidin does not affect the production of NADH and FADH2 during the early stages of cellular respiration.) What are the 3 requirements inputs for oxidative phosphorylation? I) 4 C. Net redox reaction in acetyl CoA formation and the citric acid cycle oxidative phosphorylation input. Why is the citric acid cycle a cyclic pathway rather than a linear pathway? Oxidative phosphorylation" that the NADH and the FADH2 return to their "empty" forms NAD+ FADH2, the author meant FAD when referring to the "empty" forms, right? In mitochondrial electron transport, what is the direct role of O2? What are the inputs of oxidative phosphorylation? View the full answer. How do biological systems get electrons to go both ways? Does the glycolysis require energy to run the reaction? NADH is no longer converted to NAD+, which is needed for the first three stages of cellular respiration. In this review, we present the current evidence for oxidative stress and mitochondrial dysfunction in . In the electron transport chain, electrons are passed from one molecule to another, and energy released in these electron transfers is used to form an electrochemical gradient. If you look in different books, or ask different professors, you'll probably get slightly different answers. Direct link to markemuller's post It says above that NADH c, Posted 6 years ago. What would happen to the energy stored in the proton gradient if it weren't used to synthesize ATP or do other cellular work? Why is the role NAD+ plays so important in our ability to use the energy we take in? Drag each compound to the appropriate bin. Oxidative phosphorylation is a process involving a flow of electrons through the electron transport chain, a series of proteins and electron carriers within the mitochondrial membrane. Oxidative phosphorylation is made up of two closely connected components: the electron transport chain and chemiosmosis. C) 6 C What is substrate level. This potential is then used to drive ATP synthase and produce ATP from ADP and a phosphate group. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo The same pigments are used by green algae and land plants. Label the arrows indicating electrons carried by NADH. In fermentation, the NADH produced by glycolysis is used to reduce the pyruvate produced by glycolysis to either lactate or ethanol. Direct link to breanna.christiansen's post What is the role of NAD+ , Posted 7 years ago. Redox homeostasis is a delicate balancing act of maintaining appropriate levels of antioxidant defense mechanisms and reactive oxidizing oxygen and nitrogen species. For instance, some intermediates from cellular respiration may be siphoned off by the cell and used in other biosynthetic pathways, reducing the number of ATP produced. This, as noted previously, occurs in the Calvin Cycle (see HERE) in what is called the dark phase of the process. Cellular respiration is a nexus for many different metabolic pathways in the cell, forming a. Cyanide acts as a poison because it inhibits complex IV, making it unable to transport electrons. is the final electron acceptor of the electron transport chain. If a compound is not involved in oxidative phosphorylation, drag it to the "not input or output" bin. Direct link to timroth500's post You must remeber that lif, Posted 7 years ago. This process, in which energy from a proton gradient is used to make ATP, is called. The production of ATP during respiration is called oxidative phosphorylation. An acetyl group is transferred to conenzyme A, resulting in acetyl CoA. Besides chlorophylls, carotenes and xanthophylls are also present, allowing for absorption of light energy over a wider range. These reactions take place in the mitochondrial matrix. In the oxidation of pyruvate to acetyl CoA, one carbon atom is released as CO2. Pyruvate travels into the mitochondrial matrix and is converted to a two-carbon molecule bound to coenzyme A, called acetyl CoA. ________ donates electrons to the electron transport chain. Two net ATP are made in glycolysis, and another two ATP (or energetically equivalent GTP) are made in the citric acid cycle. A) 2 C Which of these statements is the correct explanation for this observation? Photons from the sun interact with chlorophyll molecules in reaction centers in the chloroplasts (Figures \(\PageIndex{1}\) and \(\PageIndex{2}\)) of plants or membranes of photosynthetic bacteria. the microbial world. Citric acid cycle. If cyanide poisoning occurs, would you expect the pH of the intermembrane space to increase or decrease? What are the inputs and outputs of oxidative phosphorylation? As the electrons travel through the chain, they go from a higher to a lower energy level, moving from less electron-hungry to more electron-hungry molecules. These reactions take place in the cytosol. Direct link to SanteeAlexander's post I thought it was 38 ATPs , Posted 6 years ago. The dark cycle is also referred to as the Calvin Cycle and is discussed HERE. Explain why only small amounts of catalysts are needed to crack large amounts of petroleum. The input is NADH, FADH 2, O 2 and ADP. The energy from this oxidation is stored in a form that is used by most other energy-requiring reactions in cells. The interior of a leaf, below the epidermis is made up of photosynthesis tissue called mesophyll, which can contain up to 800,000 chloroplasts per square millimeter. Most affected people are diagnosed in childhood, although there are some adult-onset diseases. Dinitrophenol (DNP) is a chemical that acts as an uncoupling agent, making the inner mitochondrial membrane leaky to protons. Oxygen continuously diffuses into plants for this purpose. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl CoA stops. Is it lungs? C) It is the formation of ATP by the flow of protons through a membrane protein channel. Figure \(\PageIndex{6}\): Complexes in the thylakoid membrane. Direct link to Maulana Akmal's post how does the nadh from gl, Posted 7 years ago. Yes. Indicate whether ATP is produced by substrate-level or oxidative phosphorylation (d-f). the inputs of the oxidative phosphorylation is - NADH and FADH2,these two molecules get oxidized and transfers electrons to different complexes present at the inner membrane of mitochondria, while transferring electrons protons are transferred to in . NADH -- Fe-S of Complex I -- Q -- Fe-S of Complex III -- Cyt c-- Cyt a of Complex IV -- O2, Chapter 8 Dynamic Study Module: An Introducti, David N. Shier, Jackie L. Butler, Ricki Lewis, John David Jackson, Patricia Meglich, Robert Mathis, Sean Valentine, Jane B. Reece, Lisa A. Urry, Michael L. Cain, Peter V Minorsky, Robert B Jackson, Steven A. Wasserman. The energy from this oxidation is stored in a form that is used by most other energy-requiring reactions in cells. Net Input: Acetyl CoA, NAD+, ADP Net Output: Coenzyme A, CO2, NADH, ATP Not Input or Output: Pyruvate, Glucose, O2 (In the citric acid cycle, the two carbons from the acetyl group of acetyl CoA are oxidized to two molecules of CO2, while several molecules of NAD+ are reduced to NADH and one molecule of FAD is reduced to FADH2. It is sort of like a pipeline. In plants and algae, the pigments are held in a very organized fashion complexes called antenna proteins that help funnel energy, through resonance energy transfer, to the reaction center chlorophylls. As they are passed from one complex to another (there are a total of four), the electrons lose energy, and some of that energy is used to pump hydrogen ions from the mitochondrial matrix into the intermembrane space. Six-carbon glucose is converted into two pyruvates (three carbons each). The effect of gramicidin on oxidative phosphorylation Citric Acid Cycle ("Krebs cycle"), this step is the metabolic furnace that oxidizes the acetyl CoA molecules and prepares for oxidative phosphorylation by producing high energy coenzymes for the electron transport chain - "energy harvesting step" - Input = one molecule of acetyl CoA - Output = two molecules of CO2, three molecules of NADH, one . Phosphorylation is the addition of a phosphoryl (PO 3) group to a molecule. Inputs and Outputs Output is the information produced by a system or process from a specific input.