...Enzymology and Catalytic Mechanisms GRT3 Enzymes are proteins that speed up chemical reactions. They are catalyst. Without catalyst, chemical reactions would still take place, but at a slower rate and the body wouldn’t benefit. All enzymes possess two essential properties. First, enzymes accelerate the rate of chemical reactions without being consumed and/or changed by the reaction. Second, enzymes accelerate reaction rates without changing the chemical equilibrium among reactants and products. Each enzyme has a receptor site, and they are very specific to which molecule (substrate) it will interact with. When a substrate is captured, it will either be combined to create a product or it will be broke down. Fructose is primarily metabolized in the liver. Fructose alone cannot be used as energy. It has to be broke down for use. Enzymes in the liver aid fructose metabolism. Fructose binds to the receptor site on the enzyme fructokinase. This enzyme uses ATP and ADP cycle (energy) to speed up the chemical reaction to convert fructose into Fru-1-p. Next, Fru-1-p will undergo the next reaction and will produce either DHAP or glyceraldehyde by way of the enzyme Aldolase B. (Wikipedia, 2015) As stated above, Aldolase B is active specific to the substrate Fructose-1-Phosphate. Fructose-1-phos is derived from fructose. It’s produced by fructokinase which is available in the liver. It’s converted by aldolase B into dihydroxyacetone phosphate and glyceraldehyde. A deficiency...
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...Unit 4: Respiration ATP Point 1: What is metabolism • This refers to the chemical reactions taking place in a C_____. • There are thousands of these occurring in each cell. • To make them easier to understand they are arranged into M__________ pathways. • Reactions releasing energy are C__________ reactions (e.g. respiration); those using energy are A__________ reactions (e.g. photosynthesis). Point 2: How are respiration and photosynthesis linked? 1. Respiration is the R__________ of photosynthesis. 2. Respiration is an O__________ reaction whereas photosynthesis is a R___________ reaction, as shown here: Photosynthesis/endothermic/reduction 6CO2 + 6H2O + [Energy] C6H12O6 + 6O2 + [Energy] Respiration/exothermic/oxidation Question: What is oxidation and what is reduction? Point 3: What is ATP? • ATP consists of three P___________ groups, a R________ sugar and A____________. Draw a molecule of ATP in the space below: • ATP provides the I______________ source of energy for biological reactions in all organisms, it is said to be U_____________. • When energy is released the body does not want to use it up all at once, otherwise it might lose a lot of it as ________. • Energy is released from the B_______ between the phosphate groups in a single H_____________ reaction. It can be released it in S_______, U___________ amounts. ...
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...Metabolism Western Governors University Aston Portis 1. All enzymes are catalyst because they cause a chemical reaction to take place faster than it would on its own. It also does not get used during the reaction (Hudon-Miller, 2012). 2. (Hudon-Miller, 2012). 3. (Hudon-Miller, 2012). 4. Fructose is component of sucrose, normal table sugar, along with glucose. Whereas glucose is able to immediately enter into glycolysis, fructose is not. Fructose is broken down via fructokinase into fructose- 1-phosphate. Fructose – 1-phospate then gets converted into DHAP+ glyceraldehyde via aldolase B. DHAP+ glyceraldehyde is used in glycolysis to produce pyruvate that goes into the citric acid cycle to produce ATP (Hudon-Miller, 2012). 5. In aldolase B deficiency the substrate fructose 1- phosphate is unable to produce DHAP+ glyceraldehyde but the fructose is still getting phosphorylated by fructokinase. This causes a buildup of fructose- 1-phosphate. It is not being used in glycolysis or gluconeogenesis. There is a buildup of phosphate which causes the phosphate to get stuck and the free phosphate to be depleted by because of so much is being used by the fructose 1-phosphate. Since our phosphate levels were depleted it slows production of ATP, phosphate is needed in the electron transport chain. Since ATP production has slowed and liver cells are low on energy liver damage can occur which can ultimately lead to liver failure. Fructose-1-phosphate buildup...
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...activation energy needed to start the reaction and that is how the reaction will be sped up. Enzymes are specific for certain reactions and are proteins. Not all catalysts though are enzymes. (Sanders, 2014) 2. (Gresham HS IB Biology, 2007) 3. (Hudon-Miller, S. 2012) 4 & 5. When table sugar is consumed, it is broken down into glucose and fructose. Glucose is used in the blood stream. Glucose can be stored in the liver as glycogen. Fructose does enter glycolysis, but first two steps are original to fructose. The first step involves breaking down fructose into fructose-1 phosphate by the enzyme, fructokinase. Fructose is the substrate of fructokinase and it’s product is fructose-1 phosphate. Fructose-1 phosphate is converted into DHAP and glyceraldehyde (products), by the enzyme aldolase B which will enter the glycolysis pathway. (Hudon-Miller, S. 2012) In HFI, there is an aldolase deficiency, so there is no conversion of fructose-1 phosphate into DHAP and glyceraldehyde, so they do not enter the glycolysis pathway to produce ATP or in gluconeogenesis. The fructose is still achieving phosphorylation by fructokinase, which results in a build up of fructose-1 phosphate. The liver cells are unable to utilze fructose as energy. There becomes an abundant buildup of fructose-1 phosphate because that signal is still working, which results in the free phosphate in the blood going down. There is a decreased potential for free the phosphates to enter the electron transport chain...
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...Lactate dehydrogenase catalyzes the last step of anaerobic glycolysis. In addition to the production of ATP glycolysis also yields the pyruvate and NADH. NADH is later used in the electron transport system for generating more ATP with enzymes located with membrane of the mitochondria. When Oxygen is absent, cells must go through fermentation. The purpose of this process is to get NAD. This NAD is recycled and without this step, glycolysis would not occur. Fermentation occurs in muscle fibers during exercise. Pyruvate is converted into lactic acid by way of reduced NADH. Lactate dehydrogenase catalyzes this reaction. There are multiple forms of lactate dehydrogenase found in different muscle tissues, these forms are called isozymes. These isozymes possess different structural properties but overall have the same function. The purpose of these isozymes is the allow for the adjustments needed in metabolism. Different tissues and organs have...
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...respiration is a four step process that ultimately oxidizes glucose into ATP. The first step occurs in the cytoplasm and is called glycolysis. This stage is where glucose is broken down into pyruvate and two ATP. This pyruvate moves into the mitochondrial matrix where it is further oxidized into acetyl CoA before moving into the citric acid cycle to become NADH and FADH2. The final step occurs in the inner membrane space and is known as the electron transport chain. NADH and FADH2 donate electrons which will be shuttled between the complexes. Once the fourth complex is powered, the electron is released and accepted by oxygen. The proton motor force powers the ATP synthase by forcing hydrogen to flow through it allowing approximately 32 ATP to be synthesized....
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...photosynthesis • breaking down of carbohydrates in order to produce ATP molecules, represented as: C6H12O6 + 6O2 6CO2 + 6H2O + ATP • divided into four individual sub-pathways: - anaerobic stage, Glycolysis - a transition reaction connecting glycolysis with the krebs cycle - an electron transport chain Structure of Mithochondrion • double membranes organelle found in almost all living cells • the inner membrane is folded to form little shelves called cristae • the inner space filled with gel-like fluid is called the matrix, containing numerous enzymes • the transition reaction and the krebs cycle occur in the matrix while electron transport chain occurs in the cristae Glycolysis • takes place in the cytoplasm of every living cells • anaerobic stage of cellular respiration • breakdown of glucose to two molecules of 3-carbon compound, pyruvic acid with net gain of ATP molecules and 2 NADH • begins with energy investment step that requires two separate reactions and uses two ATP resulting to two C3 molecules • ends in energy harvesting steps wherein oxidation occurs by the removal of electrons which are accepted by NAD, and the generation of four ATP by substrate-level phosphorylation Transition Reaction: Acetyl coA Formation • serves as a bridge connecting glycolysis with the krebs cycle • takes place in the matrix of mitochondrion • each pyruvic acid molecule is split into 2-carbon acetyl group and CO2 with the production of NADH • the acetyl coenzyme A is...
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...Cellular Respiration Class, today we are going to be talking about a really cool way your body breaks down food molecules into carbon dioxide and water! First, let’s understand what exactly this means. This process is called Cellular Respiration. This happens when food molecules, such as glucose (sugar in your body) breaks down into carbon dioxide, which is an odorless gas in the air, and water. And I’m sure you all know what water is, correct? (Giggle) That’s what I thought! Now that we all understand what that means, we are going to find out what happens next! Oh boy, who’s excited? Me too! Here we go! Once the molecules are oxidized into carbon dioxide and water, the energy released is trapped in a form ATP (which I’ll be discussing in just a few minutes) so it can be used by all the energy-consuming activities of the cell! We all know what a cell is correct? We all have cells in our body that help us function and stay alive! Well, when this happens, it occurs in two parts! First, the glucose breaks down to pyruvic acid. And everyone remembers what glucose is, right? That’s right, the sugar in our bodies! So let’s figure out of pyruvic acid is! It is a yellowish acid that occurs in metabolic processes, which is necessary for life! So it is very important for this part to happen, correct? There is another part of this we are going to be discussing next. The next step is when it completely oxidizes the pyruvic acid into the carbon dioxide and water! What color is the pyruvic...
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...enzyme-substrate complex. An enzyme will act in a specific way on the substrate that it is bound to in order to change it into a product, and at the end of the process, the enzyme is unchanged and ready to bind to the next substrate. An enzyme acts as a catalyst, something that lowers the energy required to complete a chemical reaction (activation energy) without itself being changed. (Hudon-Miller, 2012) In the case of fructose breakdown, an enzyme called fructokinase is responsible for splitting fructose into fructose 1-phosphate, a six-carbon fructose. Another enzyme called aldolase B splits fructose 1-phosphate into two three-carbon molecules, dihydroxyacetone phosphate (DHAP) and glyceraldehyde. These products are then able to enter the glycolysis pathway to be converted to pyruvate, which is essential for the citric acid cycle and the production of adenosine triphosphate (ATP) for cellular energy. A2. Deficiency in Aldolase B A hereditary deficiency in aldolase B could be caused by mutations in the ALDOB gene. An aldolase B deficiency will prevent the breakdown of fructose past the point of the fructose 1-phosphate stage. This causes fructose-1-phosphate to build up in the liver, and the depletion of phosphates that are needed for ATP production. Therefore, the synthesis of glucose (gluconeogenesis) cannot happen. Furthermore, glycogenolysis (the breakdown of glycogen into glucose) is prevented. If a...
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...whereas hetrolactic will also produce a carbon dioxide and ethanol. Ethanol fermentation produces just carbon dioxide and ethanol. The difference between ethanol and hetrolactic fermentations is that hetrolactic fermentation will also produce a lactic acid, whereas ethanol fermentation does not. Ethanol and Homolactic fermentations are the two most common forms of fermentation, but others include ABE and mixed acid. Glucose is taken in yeast by facilitated diffusion. Proteins allow glucose to move through the cell membrane. Glucose is taken in, in relation to the amount hexokinases that are used in glycolysis. The glucose will collide into a protein channel, opening the channel to allow the glucose through. Sugars are detected by a two protein structure known as TAS1P2+3. Once glucose is taken in, it is either stored in a vacuole or turned in ATP, NADH, and pyruvic acid by glycolysis. More complex sugars are taken in by similar methods. Once a polysaccharide is taken in it will be broken down by an enzyme. The enzymes that break apart these polymers do so through a method called hydrolysis. Once a monomer is removed it is converted into glucose through other enzymes. In anaerobic cellular respiration, glucose is first broken down into pyruvic acid through several steps. First glucose is turned into glucose 6-phosphate, or G6P, by means of an enzyme called hexokinase using an ATP. Then glucose-6-phosphate isomerase (GPI) transforms G6P into fructose 6-phosphate (F6P). F6P then binds...
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...in eukaryotic organisms (plants, animal). It occurs in the mitochondria. There are three stages glycolysis, Krebs cycle, and electron transport chain (ETC). There are two equations of aerobic cellular respiration. The first one is glucose (C6 H12 O6) plus oxygen (O2) produce carbon dioxide(CO2) and water (H2O). The second one is adenosine diphosphate (ADP) plus phosphate (Pi) produce adenosine triphosphate (ATP). Glycolysis is the first stage of aerobic cellular respiration. Glycolysis occurs in the cytoplasm of the cell. Glycolysis purpose is to break down glucose. The reactants...
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...Biochemical Implications in Metabolic Disorders Kim Wertz Western Governors University Biochemistry 208.5.4-01-208.5.5-07 WGU August 7, 2013 Biochemical Implications in Metabolic Disorders Enzymes play an important role and are involved in the process of fructose breakdown. The enzymes are catalysts, meaning, they work to lower activation energy without using the reaction. Sucrose is plain table sugar and it is broken down into glucose and fructose that needs to be broken apart. This process known as glycolysis will break down glucose-producing pyruvate and then it goes into the citric acid cycle to produce ATP. Fructose will break down first, forming fructose 1-phosphate by the enzyme, fructokinase. Aldolase B then will convert the fructose 1-phosphate into DHAP and glyceraldehyde as they enter into the glycolysis pathway. When there is a deficit or a mutation of Aldolase B gene, then hereditary fructose intolerance will occur. Individuals are usually asymptomatic until they ingest sucrose, fructose or sorbitol. When the fructose is ingested, there is a block of the Aldolase B, which will cause an increase of the F1P. This is an autosomal recessive condition from mutation of the Aldolase gene. As of 1991, there have been eight structural defects found in the Aldolase B gene, as documented by Wikipedia. Mutant alleles result in many different mutations; one being base pair substitutes, small deletions, and areas of the splicing regions of...
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...). The first step in Photosynthesis is the “light reaction”. This is when the electromagnetic energy of sunlight is converted into the chlorophyll (the pigment that absorbs the sunlight) containing cells of photosynthetic organisms (Audesirk T, Audesirk G, Byers G, 2008). Chlorophyll is packed into stacks of membranes called grana where the sunlight is absorbed. The sunlight is then converted into chemical energy or Oxygen. This is then converted into sugars or glycolysis. If oxygen is present when the glycolysis process is complete, a type of cellular respiration called aerobic respiration is created. During the aerobic respiration a process called TCA is administered. The TCA cycle releases energy store in pyruvate. This energy is called ATP, which is the energy source that is used for nearly every task in the human body and other organisms. Anaerobic respiration is the absence of oxygen. Anaerobic respiration begins with the same process as aerobic respiration. However; if after the glycolysis is broken down and there is no presence of oxygen. Anaerobic respiration is formed. This form does not enter the TCA cycle or electron transport. Photosynthesis and respiration are complementary processes. During photosynthesis the green plants absorb solar energy and remove carbon dioxide form the atmosphere to produce...
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...the first two steps of fructose metabolism in the liver. Fructose in the blood passes through the cell membrane into the liver cell and initiates phosphoralation with fructokinase for the metabolism of fructose. The fructokinase then uses the phosphate and produces F-1-P (fructose 1 phosphate). F-1-P is the substrate for the enzyme Aldolase B. Aldolase B takes the F-1-P and makes DHAP and glyceraldehyde, the products of Aldolase B. The DHAP and glyceraldehyde are intermediates in glycolysis and continue down to make pyruvate which then can make ATP synthesis or fatty acids. (Sanders, J. 2013) A5. Discuss how a deficiency in aldolase B is responsible for HFI. Hereditary Fructose Intolerance (HFI) results from a deficiency of aldolase B activity primarily in the liver, but also in the kidneys and small intestine. If aldolase B doesn’t work, then there is no effect on fructokinase, there is no effect on the enzyme that separates glucose and fructose and no effect on the enzymes working on glycolysis. Only aldolase B is used. So, the fructose still gets converted to the fructose-1-phosphate, but without aldolase B, it cannot be converted to DHAP and glyceraldehyde. The lack of the aldolase B enzyme...
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...photosynthesis • breaking down of carbohydrates in order to produce ATP molecules, represented as: C6H12O6 + 6O2 6CO2 + 6H2O + ATP • divided into four individual sub-pathways: - anaerobic stage, Glycolysis - a transition reaction connecting glycolysis with the krebs cycle - an electron transport chain Structure of Mithochondrion • double membranes organelle found in almost all living cells • the inner membrane is folded to form little shelves called cristae • the inner space filled with gel-like fluid is called the matrix, containing numerous enzymes • the transition reaction and the krebs cycle occur in the matrix while electron transport chain occurs in the cristae Glycolysis • takes place in the cytoplasm of every living cells • anaerobic stage of cellular respiration • breakdown of glucose to two molecules of 3-carbon compound, pyruvic acid with net gain of ATP molecules and 2 NADH • begins with energy investment step that requires two separate reactions and uses two ATP resulting to two C3 molecules • ends in energy harvesting steps wherein oxidation occurs by the removal of electrons which are accepted by NAD, and the generation of four ATP by substrate-level phosphorylation Transition Reaction: Acetyl coA Formation • serves as a bridge connecting glycolysis with the krebs cycle • takes place in the matrix of mitochondrion • each pyruvic acid molecule is split into 2-carbon acetyl group and CO2 with the production of NADH • the acetyl coenzyme A is...
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