Energy is needed by living organisms to perform work in their daily life. In plants, energy originates from the Sun as light energy and converted to carbohydrate, fat and protein while in human beings and animals, energy originates from the source of food through Krebs cycle. Krebs cycle is defined as “a central part of the energetic metabolism that contributes to the generation of ATP by the chemical breakdown of carbohydrates, fats and proteins. It is a series of chemical reactions catalysed by enzymes occurring in the inside of mitochondria called the matrix and which can be disposed circularly” (Nazaret, Heiske, Thurley, & Mazat, 2008, p. 455).There are eight important steps involving in the process of Krebs cycle in metabolism namely condensation, isomerisation, first oxidative decarboxylation, second oxidative decarboxylation, synthesis of succinyl-CoA, oxidation of succinate, hydration of carbon double bond and lastly, regeneration of oxaloacetate (refer to Figure 1 in Appendix 1). In the first step in process of Krebs cycle in metabolism is the condensation reaction. The condensation process is “the acetic acid subunit of acetyl coenzyme A (acetyl-CoA) strips off the CoA portion from acetyl-CoA” (Tortora, Funke, & Case, 2010, p. 128). The remaining two carbons are combined with the oxaloacetate which is four carbons to form a molecule of citrate which is six carbons molecule. In this process, the acetyl coenzyme A acts only as a transporter of acetic acid from one enzyme to another. This is because the coenzyme is released by hydrolysis from the molecule so that it combines with another acetic acid molecule to begin the Krebs cycle again (Reece, Urry, Cain, Wasserman, Minorsky, & Jackson, 2011). The citric acid molecule undergoes an isomerisation of citrate in the second step in the process of the Krebs cycle in metabolism. Reece et al. (2011) defined isomer as “The isomer is one of several compounds with the same molecular formula but different structures and therefore different properties. There are three types of isomers are structural isomers, cis-trans isomers, and enantiomers” (p. 108). During this process, the hydroxyl group and a hydrogen molecule are removed from the citric structure in the formed of the water molecule (H2O). In the same time, the two carbons form a double bond between the molecules. Next, the water molecule is added back in the process. Then, the hydroxyl group and hydrogen molecule are reversed with the respect to the original structure of the citric molecule (Reece et al.
In the presence of oxygen there are 4 stages namely glycolysis in the cytoplasm, link reaction and Krebs cycle in the matrix of the mitochondria and electron transport chain in the mitochondrial membranes. ATP is generated when H is lost and used to reduce coenzymes. The reduced Hydrogen carrier can be used to generate ATP by oxidative phosphorylation
... which is catalyzed by b-ketoacyl CoA thiolase. The products are acetyl-CoA and a long chain fatty acyl CoA that is 2 carbons shorter than the original fatty acyl CoA. One complete round of β-oxidation cleaves 2 carbons from the fatty acid chain, and the process continues until the entire fatty acid chain is broken down into acetyl propinoyl CoA. For example, an 18 carbon chain fatty acid would need to go through 9 rounds of β-oxidation in order to be completely metabolized.
Animal metabolism consists of the utilization of nutrients absorbed from the digestive tract and their catabolism as fuel for energy or their conversion into substances of the body. Metabolism is a continuous process because the molecules and even most cells of the body have brief lifetimes and are constantly replaced, while tissue as a whole maintains its characteristic structure. This constant rebuilding process without a net change in the amount of a cell constituent is known as dynamic equilibrium (Grolier1996). In the combustion of food, oxygen is used and carbon dioxide is given off. The rate of oxygen consumption indicates the energy expenditure of an organism, or its metabolic rate (Grolier1996).
The citric acid cycle is an amphibolic pathway. It utilises both anabolic and catabolic reactions; the first reaction of the cycle, in which oxaloacetate (a four carbon compound) condenses with acetate (a two carbon compound) to form citrate (a six carbon compound) is typically anabolic. The production of the isomeric isocitrate is simply intramolecular rearrangement. The subsequent two reactions are typically catabolic, producing succinate (a four carbon compound), which is then oxidised, forming fumarate (a four carbon compound). Water addition produces malate and then oxidised for regeneration of oxaloacetate. Thus the cycle can be seen to exhibit both anabolic and catabolic processes to form its intermediates.
A hypothetical defect of the enzyme succinic coenzyme A synthetase, would have catastrophic effects, as it is one of the central catalysts involved in the Citric Acid Cycle. It is the only enzyme in the citric acid cycle that produces GTP or ATP through substrate level phosphorylation. The rest of the enzymes produce products that go on to the electron carrier chain, and ultimately produce ATP, but in the Citric Acid Cycle Succinyl Coenzyme synthetase is the only enzyme responsible for producing GTP.
Energy is required for cells to perform various cellular activities to function such as growth and reproduction. That process of breaking organic compound, which will be food in this case, into oxygen to be used to convert into Adenosine Triphosphate or ATP for energy. Specifically this would be called Aerobic Respiration as the process uses oxygen. It’s literally how we get energy from eating and such. There are three process that occur: glycolysis, the Kreb Cycle and the Electron Transport Chain. This occurs in and outside of the mitochondria. For bacterial, the process will occur in the membrane sometimes without the presence of oxygen which is called anaerobic respiration. The first process is glycolysis which occurs in the cytosol of the cell. The food that we eat will be broken down into glucose. Glucose, a six
It is the slowest working metabolic pathway for the production of energy in the body. This cycle, unlike the energy consumption in sprinting, allows the body to maintain its energy level during endurance activities. The citric acid cycle, or the Krebs cycle, allows humans to sustain long-term energy (long running) because it produces more energy than the other pathways. The Krebs cycle uses lots of enzymes, which reduce the amount of energy required for a chemical reaction. These enzymes help the body use less and create more energy. By using enzymes in the absence of more energy, the Krebs cycle is different from other metabolic pathways. Through the catabolism of fats, sugars, and proteins, an acetate is created and used in the citric acid cycle. The Krebs cycle converts NAD+ into NADH. These are then used by another system called the oxidative phosphorylation pathway to generate
Aconitase catalyzes the conversion of citrate to isocitrate in the mitochondria and cytosol. In the mitochondria, aconitase is required for the TCA cycle to continue. In the case of high mitochondrial ROS production, aconitase becomes oxidized and no longer functions...
When citrate is not able to produce from mini-cycle, oxaloacetate can be used to produce pyruvate so that it helps regulate the cycle. For the disadvantage, if either oxaloacetate or alpha-ketoglutarate way is blocked, citrate cannot be produce and fatty acid synthesis will rarely happen (436). For the advantage of protein metabolism will be regulation of energy by oxaloacetate and producing aspartate immediately. During the Krebs bicycle, aspartate used in urea synthesis is regulated from oxaloacetate. Since these two factors can be produced faster in the mini-cycle than other places, it is benefit. For the disadvantage, if oxaloacetate way is blocked, then Kreb bicycle will not run well due to lack of aspartate and oxaloacetate
During catabolism, chemical energy such as ATP is released. The energy released during catabolism is released in three phases. During the first phase, large molecules are broken down. These include molecules such as proteins, polysaccharides, and lipids. These molecules are converted into amino acids and carbohydrates are converted into different types of sugar. The lipids are broken down into fatty acids
The indirect applications are based on the idea that without ATP synthase, cellular respiration would achieve very little. This includes religious fasting and bioremediation. During religious fasting, there is generally little to no fresh input of nutrient. So the body must use fat reserves in the body to perform cellular respiration. The lipids stored in the body take a related metabolic pathway. Eventually the energy extracted from the fat fuels ATP synthase that makes ATP to be used by the body for energy, even though there is no input of nutrients. Bioremediation is the use of genetically modified organism to eat away at pollutants in the soil water. ATP synthase is related to this process as the waste becomes the input of nutrient that takes a related metabolic pathway for cellular respiration that occurs in the cells of the organism. Eventually the waste’s energy is used to create a concentration gradient and ATP synthase creates ATP to continue fueling the degradation of the pollutants. The direct applications of ATP synthase is the contributions to the light independent reactions. ATP synthase creates ATP to be used in the Calvin cycle. The importance of the Calvin cycle is that it takes the energy from the light dependent reaction and creates a sugar to be sent to cellular respiration. This process requires energy, which is provided by ATP synthase. This enzyme is
In metabolism, complex molecules are degraded into simpler products including amino acids, glucose, and fatty acids. These simpler molecules can subsequently be broken down into the Acetyl CoA intermediate (Voet, D., Voet, J., Pratt, C. 2006. p. 397). Acetyl CoA then enters the citric acid cycle (TCA cycle), and is oxidized into carbon dioxide, CO2. During the TCA cycle, NAD+ and FADH are reduced to produce high transfer potential electrons, NADH and FADH2. 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).
Our metabolism, “the totality of an organism’s chemical reactions”, manages energy usage and production of cells. We use energy constantly and our metabolism breaks down food through complex chemical reactions into energy our cells
Kreb's cycle is when several things are converted into carbon dioxide energy and water. These that are converted are proteins, fats and carbohydrates. The ATP is what makes or helps the cells use energy in order to synthesize proteins from amino acids. Another thing that is done is DNA is being replicated. You will hear the kreb's cycle called he citric acid cycle or the TCA cycle.
When humans consume plants, the carbohydrates, lipids, and proteins that are broken down through two forms of cellular respiration. The two processes of cellular respiration displayed in humans are anaerobic or aerobic. The deciding process used depends on the presence of oxygen. Cellular respiration converts the material into useable energy called ATP. ATP is the energy form that cells can use to perform their various functions and it can also be stored for later use. Without plants, none of this energy could be produced and the herbivores that humans consume would not exist.