The Citric Acid Cycle

The krebs cycle is the second step in aerobic respiration of cells, which takes place in the matrix of the mitochondria of eukaryotic cells. This process is to oxidize pyruvate.

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

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 is the series of metabolic process by which living cells produce energy through the oxidation of organic substances. Cellular respiration takes place in the mitochondria. Fermentation is the process by which complex organic compounds such as glucose, are broken down by the action of enzymes into simpler compounds without the use of oxygen. The significance of these pathways for organisms is to allow for an organism to be able to generate ATP. Some organism that undergo cellular respiration are bacteria and fungi. Some organism that undergo fermentation are yeast and muscle cells. In cellular respiration, glucose is oxidized and releases energy. In cellular respiration, glucose produces ATP and 3-carbon molecules of pyruvate. The pyruvate is then further broken down in the mitochondria where it becomes oxidized and releases CO2 (Upadhyaya 2014). In the fermentation process oxygen does not play a part. This process converts glucose into pyruvate and produces ATP. From there pyruvate breaks down into CO2 and acetaldehyde (Upadhyaya 2014) Monosaccharides are known as simple sugars and their main function is being the source of energy for organisms. Disaccharides are two monosaccharides joined by a covalent bond and their primary function is to provide food to monosaccharides. Some disaccharides

The citric acid cycle, also called the Krebs cycle or the tricarboxylic acid, TCA, cycle, a series of chemical reactions that generates energy from the oxidation of acetate into chemical energy and carbon dioxide in the form of ATP. It also provides NADH, which is a reducing agent that is very common in biochemical reactions. This cycle is constantly supplied with new carbon. This comes in from acetyl-CoA, which starts the entire process of the citric acid cycle. The first step of the citric acid cycle is the aldol condensation of oxaloacetate and acetyl-CoA and water with the enzyme citrate synthase in order to form citrate and CoA-SH. The next step is the dehydration of citrate with the enzyme aconitase in order to form cis-aconitate and water. Then comes the hydration of cis-Aconitate and water with the enzyme aconitase in order to form isocitrate. The next is the oxidation of isocitrate and NAD+ with the enzyme isocitrate dehydrogenase in order to form oxalosuccinate and NADH and H+. Then, there is the decarboxylation of oxalosuccinate with the enzyme isocitrate dehydrogenase in order to form alpha-ketoglutarate and carbon dioxide. Next, there is the oxidative decarboxylation of alpha-ketoglutarate and NAD+ and CoA-SH with the enzyme alpha-ketoglutarate dehydrogenase in order to form succinyl-CoA and NADH and H+ and carbon dioxide. The next step is the substrate-level phosphorylation of succinyl-CoA and GDP and Pi with the enzyme succinyl-CoA synthetase in order to form succinate and CoA-SH and GTP. Then, there is the oxidation of succinate and ubiquinone with the enzyme succinate dehydrogenase in order to form fumarate and ubiquinol. Next, is the hydration of fumarate and water with the enzyme fumarase in order to form L-malate. The final step is the oxidation of L-malate and NAD+ with the enzyme malate dehydrogenase in order to form oxaloacetate and NADH and H+. Two cycles are required for every single glucose molecule because two acetyl Co-A molecules

If a defect of an enzyme occurred in the Citric Acid Cycle it comes to a stop (Sanders,

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.

This glucose molecule then becomes the key ingredient for Mr. Euglena’s aerobic respiration, the process where glucose is broken down into molecules of ATP in the presence of oxygen. A molecule of ATP is ADP having a high energy bond with phosphate (P). When this bond is broken, it releases energy in order for the cell to carry out life functions. The glucose molecule produced by the dark reaction of photosynthesis makes its way to the cristae on the inner membrane of the mitochondria. In the cristae, the process of aerobic respiration occurs. There are three steps in aerobic respiration: glycolysis, the Krebs Cycle (citric acid cycle), and the cytochrome chain (electron transport system). The first step is glycolysis. Glycolysis

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

Acetyl CoA along with oxaloacetate will be condensed until citrate is produced. Although the kreb’s cycle is considered as an aerobic respiration, oxygen is not directly used. Glycolysis, another process that converges with the TCA cycle and it is the process of breaking down glucose. The PEP bonds from the molecules will be converted into the pyruvate molecules and this type of ATP synthesis method is known as the substrate level phosphorylation. Fatty acids are oxidized through four reactions where the fatty acid will be completely oxidized into acetyl CoA which leads to the TCA cycle. Amino acids go through two reactions: Transamination which transfers an amino acid group in into a keto acid and defamation which removes an amino acid group in the form of

Cellular repartition is a wonderful thing first there is glycolysis,which is the splitting of glucose into two 3-carbon molecules. Next there is the preparatory reaction, which divides each 3-carbon molecule into a 2-carbon molecule and CO2. Afterwards there is the citric acid also known as the Krebs cycle, which produces CO2, NADH, FADH2, and ATP. The electron transport chain also known as the electron transport system, assists in the production of the largest amount glycolisis which occurs in the cytoplasm and electron transport chain occurs in the mitochondria. The Krebs cycle produces the most CO2. Anerobic is the growing or metabolizing in the absence of oxygen. Glycolysis and fermentation are steps which anaerobic seems to occur. Chemiosmotic

The rate at which the citric acid cycle proceeds can be controlled by altering the concentration of the intermediate compounds, especially oxaloacetate concentration. The rate at which the TCA cycle proceeds can be increased if the mitochondrial concentration of oxaloacetate is increased. When higher amounts of oxaloacetate are present, higher amounts of acetate can come into the pathway to get oxidized, thereby increasing the rate of the cycle. The synthesis of oxaloacetate is from pyruvate, when the concentration of pyruvate is high, and the rate at which the TCA Cycle proceeds needs

Aerobic respiration utilises the resulting product of glycolysis (which is pyruvate) in the Krebs cycle, also known as citric acid cycle, to create much more energy in the form of ATP (Adenosine Triphosphate) . The equation for aerobic

Cellular respiration is a procedure that most living life forms experience to make and get chemical energy in the form of adenosine triphosphate (ATP). The energy is synthesized in three separate phases of cellular respiration: glycolysis, citrus extract cycle, and the electron transport chain. Glycolysis and the citric acid cycle are both anaerobic pathways because they do not bother with oxygen to form energy. The electron transport chain however, is aerobic due to its use of oxidative phosphorylation. Oxidative phosphorylation is the procedure in which ATP particles are created with the help of oxygen atoms (Campbell, 2009, p. 93). During which, organic food molecules are oxidized to synthesize ATP used to drive the metabolic reactions necessary to maintain the organism’s physical integrity and to support all its activities (Campbell, 2009, pp. 102-103).

aerobic respiration the Pyruvate enters the Citric acid cycle in which 6 CO2 (1 molecule