The ETC carries out catabolic reactions that occur in the inner mitochondrial membrane. In the ETC hydrogen’s are removed during oxidation and are combined with the O2 to form water. The energy that is released from this reaction is utilized to attach phosphate groups to ADP, which forms the desired product of ATP. This process is defined as oxidative phosphorylation. Cofactors along the membrane of the mitochondria are the primary tools used for the ETC; these can be referred to as different complexes I-V.
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 end of the glycolysis cycle diffuses into the mitochondria, where it gets oxidized. The three-carbon pyruvate loses two of its hydrogen atoms and also a carboxyl grouping.
This is achieved through a dehydration and hydration step with cis-Aconistase produced as an intermediate and the aconitase catalysing the overall reaction. The third step involves isocitrate undergoing decarboxylation and oxidation reactions to form alpha-ketoglutarate (Berg J.M et al., 2015). In step four, a second decarboxylation oxidation reaction occurs to form succinyl CoA from alpha-ketoglutarate. Step five involves splitting succinyl CoA to produce succinate and CoA. In step six, succinate is oxidised to fumurate and FADH2 is formed simultaneously (Ness B., 2017).
(HallyHosting, n.d) The next stage of glycolysis occurs in thecytoplasm of the mitochondria. This is called the link reaction, also known as oxidative carboxylation. Oxygen is required in this stage so is an aerobic respiration and completes the conversion of pyruvate. The 2 pyruvic acid molecules, or also known as pyruvate, enter into the mitochondria, where the hydrogen and carbon dioxide become removed from them creating t... ... middle of paper ... ...oup to be added to ADP. This then forms ATP.
The absorption of minerals, such as nitrates & phosphates require ATP, which are present in root hair cells. These nitrates and phosphates are used in protein and chlorophyll synthesis as well as synthesis of DNA, ATP and NADP, which are essential to the plants growth. However, the mineral salts which are carried in solution by the symplast or apoplast pathway need to cross the endodermal barrier, which is impermeable. They cross the endodermal barrier by active transport and continue their journey in solution as ions in the xylem. In conclusion, ATP is adapted to its function and is probably one of the most important molecules in biological processes; it is produced in the mitochondria but is used all over the human body and is equally important in plants, where it is produced in the thylakoids.
These NADH and FADH2 molecules are oxidized during oxidation phosphorylation and the electron transport chain and generate water, H2O and ATP (Voet et al. 2006. p. 397). Intermediates formed from the citric acid cycle are important precursors and building blocks for producing important materials in an organism. These intermediates are drained from the TCA cycle in cataplerotic reactions to synthesize important products such as glucose, fatty acids, and amino acids. For example, gluconeogenesis, the synthesis of glucose, requires oxaloacetate that has been converted to malate, while fatty acid biosynthesis utilizes acetyl CoA, and amino acid biosynthesis utilizes oxaloacetate and α -ketoglutarate (Tymoczko, J. L., Berg, J. M., & Stryer, L. 2013. p. 339).
This process may also be known as the Kreb’s Cycle, or the Tricarboxylic Acid Cycle (TCA). Coenzyme A and Acetyl CoA feed into the TCA cycle to power it. First, pyruvate is transported into the matrix by Pyruvate Dehydrogenase and precedes the TCA cycle. Coenzyme A forms the high-energy bonds with the organic acids, and acetyl CoA is formed by pyruvate dehydrogenase. The purpose of the TCA cycle is to metabolize Acetyl CoA and conserve energy produced in the forms of other coenzymes such as NADH and FADH2.
The third route for pyruvate degradation is directly to acetate by pyruvate oxidase. Phosphoenolpyruvate, which also is a product of glycolysis, can too enter the mixed acid fermentation. It can form pyruvate and a molecule of ATP or form oxaloacetate in the presence of carbon dioxide by phosphoenolpyruvate carboxylase. Oxaloacetate is then hydrogenated by malate dehydrogenase and NADH to malate and NAD+. The enzyme fumarase turns malate into fumarate and water.
It has an interesting feature, the mitochondria has a double membrane where the internal membrane is folded up and this where the cell respiration takes place. Also mitochondria have own DNA and its own set of ribosomes. (Clamp, 2000, pg. 92) Another important organelle is a Golgi apparatus; it is a collection of membranes and vesicles. The Golgi body is an organelle with a number of functions, including the synthesis of glycoproteins; the secretion of enzymes and hormones; and the
The final step contains a phrase "coupled to." This means that the compound (NADH2) must be present and have been oxidized for the synthesis of ATP, similar to a catalyst's presence of some reactions. Although the mitochondrion's major purpose is to supply the cell with the much needed ATP, it has others. Included in this list are nitrogen metabolism, porphyrin synthesis and steroid hormone synthesis. III.