Respiration can be defined as the oxidation of the end products of glycolysis with the storage of the energy in the form of ATP. Cellular respiration occurs when oxygen is available, and the products are carbon dioxide and water. There are three main pathways in the cellular respiration process. These are: pyruvate oxidation, the citric acid cycle, and the respiratory chain.
Pyruvate oxidation in eukaryotic cells occurs inside the mitochondrion in the inner membrane, and in prokaryotes on the inner face of the plasma membrane. This step is the crucial link between the steps of glycolysis and cellular respiration. In this step, pyruvate is oxidized into acetate. Pyruvate from the
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The energy that does get released gets stored in NADH+H+. The next part of the reaction chain is when the five-carbon alpha-k molecule gets oxidized into a four-carbon molecule called succinate. Here again, carbon dioxide is released, some energy is preserved with the combination of CoA and succinate, and some of the oxidation energy is stored in NADH+H+ again. The energy that is in the succinyl CoA is then removed and used to make GTP from GDP and Pi. This is an example of phosphorylation on the substrate level. Next, ADP is used to make ATP by using GTP. More free energy gets released when the succinyl CoA gets oxidized to yield fumarate. During this, two more hydrogens are moved to an enzyme that has the carrier FAD. One more NAD+ reduction occurs and makes oxaloacetate from malate. Water is added, which makes an OH- group, and the hydrogen from the group gets taken off in the next step to make NAD+ reduce to NADH+H+. Water is used here, and in turn provides lots f energy because of its abundance. The finishing product that we have is oxaloacetate, however, this process has to be repeated again. The final product gets to combine with another CoA and go around the whole circle again. This happens two times per glucose that goes through glycolysis. The CAC reactions together are one of the most efficient energy gatherers of any of the systems along the process of respiration. The end outputs of the CAC are: 2 carbon dioxide molecules, ATP, 2
Aerobic respiration happens only when oxygen is presented in the cell. Aerobic respiration starts with pyruvate crossing into the mitochondria. When it passes through, a Coenzyme A will attach to it producing Acetyl CoA, CO2, and NADH. Acetyl CoA will enter into the Krebs cycle. In the Krebs cycle Acetyl CoA will bound with Oxaloacetic Acid (OAA), a four carbon molecule, producing the six carbon molecule, Citric Acid. Citric Acid will reorganize into Isocitrate. This will lose a CO2 and make a NADH turning itself into alpha ketoglutarate, a five carbon molecule. Alpha ketoglutarate will turn into an unstable four carbon molecule, which attaches to CoA making succinyl CoA. During that process a CO2 and NADH is made. An ATP is made when CoA leaves and creates Succinate. This molecule is turned into Fumarate, creating two FADH2 in the process. Then Fumarate is turned into Malate then into OAA making two NADH. Only two ATP is produced in Krebs cycle but the resulting NADHs and FADH2s are passed through an electron transport chain and ATP synthase. When the molecules passes through that cycle a total of 28 ATP molecules are produced. In all aerobic respiration produces 32 ATP and waste products of H2O and
Cellular respiration: C6H12O6 + 6O2 → 6CO2 + 6 H2O + 36 or 38 ATP
Oxidation of NADH and FADH2to H2O (and NAD or FAD). Generates H ion concentration gradient and therefore ATP.
Cellular respiration is a redox reaction that combines glucose & oxygen to produce carbon dioxide, water, and energy.
Respiration consists of a complicated series of chemical reactions. The first step of cellar respiration, called glycolysis, takes place in the cytoplasm. The two main components are oxygen and
In contrast, there are four metabolic stages happened in cellular respiration, which are the glycolysis, the citric acid cycle, and the oxidative phosphorylation. Glycolysis occurs in the cytoplasm, in which catabolism is begun by breaking down glucose into two molecules of pyruvate. Two molecules of ATP are produced too. Some of they either enter the citric acid cycle (Krebs cycle) or the electron transport chain, or go into lactic acid cycle if there is not enough oxygen, which produces lactic acid. The citric acid cycle occurs in the mitochondrial matrix, which completes the breakdown of glucose by oxidizing a derivative of pyruvate into carbon dioxide. The citric acid cycle produced some more ATPs and other molecules called NADPH and FADPH. After this, electrons are passed to the electron transport chain through
Acetyl-CoA is catalyzed with oxaloacetate and water to form citric acid and a hydrogen ion. A proton is transferred from Acetyl-CoA, producing oxaloacetate which produces an enzyme bound intermediate, (s) Citroyl-CoaA which is immediately hydrolyzed to form citrate.
Uniquely, glycolysis is both anaerobic and aerobic. The end product pyruvate, from glycolysis, is anabolized to lactic acid when there is a need for energy without an adequate supply of oxygen available. This last step or reaction enables glycolysis to continue producing ATP without the need for oxygen, which is why it is called the anaerobic energy system (Fink, 2009).
This process does not require oxygen and is referred to as fermentation. This process partially breaks down carbohydrates and it obtains a small amount of energy, again in the form of ATP. Pyruvic acid has to be broken down in respiration when formed by breaking down of glucose molecules, this can't be done in the same way as in aerobic respiration. When anaerobic respiration is taking place carbon dioxide and ethanol is formed.
Cellular respiration is the group metabolic reactions that happen in the cell of living organism that creates adenosine triphosphate, ATP, from biochemical energy. The formula for cellular respiration is C6H12O6 +6O26CO2+6H2O+ATP. This formula means glucose and oxygen are turned into water,carbon dioxide and adenosine triphosphate (ATP) energy through chemical reactions. Cellular respiration occurs in all cells which allows them to grow. Raphanus raphanistrum subsp. Sativus seed, also known as radish seed, undergo cellular respiration because they are not yet able to perform photosynthesis, which is how plants create their energy. Hymenoptera formicidae,commonly known as ants, undergo cellular respiration to produce the energy they need to live.
oxidation in the mitochondria within each cell. Carbohydrates, proteins, and fats can all be metabolized as
The two carbon molecule bonds four carbon molecule called oxaloacete forming a carbon molecule knew as citrate. The second step reaction is classified as oxidation/reductions reactions. This process is formed by two molecule of CO2 and one molecule of ATP. The cycle electrons reduce NAD and FAD, which join the H+ ions to form NADH and FADH2, this result to an extra NADH being formed during the transition. In the mitochondrion, four molecules of NADH and one molecule of FADH2 are produced for each molecule of pyruvate, two molecules of pyruyate enter the matrix for each molecule of oxidized glucose, as a result of these eight molecules of NADH+ two molecules are produced. Six molecules of NADH+, molecules of FADH2 and two molecules of ATP synthesize itself in Krebs cycle. As a result, no oxygen is used in the described reactions. During chimiosmosis, oxygen only plays a role in oxidative phosphorylation. The next step is the electron transport; the electrons are stored on NADH and FADH2 and are used to produce ATP. Electron transport chain is essential to make most ATP produced in cellular respiration. The NADH and FAD2 from the Krebs cycle drop their electrons at the beginning of the transport chain. When the electrons move along the electron transport chain, it gives power to pump the hydrogen along the membrane from the matrix into the intermediate space. This process forms a gradient concentration forcing the hydrogen through ATP syntheses attaching
Glycolysis is followed by the Krebs cycle, however, this stage does require oxygen and takes place in the mitochondria. During the Krebs cycle, pyuvic acid is broken down into carbon dioxide in a series of energy-extracting reactions. This begins when pyruvic acid produced by glycolysis enters the mitochondria. As the cycle continues, citric acid is broken down into a 4-carbon molecule and more carbon dioxide is released. Then, high-energy electrons are passed to electron carriers and taken to the electron transport chain. All this produces 2 ATP, 6 NADH, 2 FADH, and 4 CO2 molecules.
order to convert biochemical energy to ATP and release waste. Most of the steps are
In the metabolic reactions, oxidation-reduction reactions are very essential for ATP synthesis. The electrons removed in the oxidation are transferred to two major electron carrier enzymes. The electrons are transported through protein complexes in present in the inner mitochondrial membrane. The complexes contain attached chemical groups which are capable of accepting or donating one or more electrons. The protein complexes are known as the electron transfer system (ETS). The ETS allow distribution of the free energy between reduced coenzymes and the O2. The ETS is associated with proton (H+) pumping from the mitochondrial matrix to intermembrane space of the mitochondria.