No of Atp Formed in Krebs Cycle
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Amphibolic Nature of Krebs Cycle
Amphibolic nature of Krebs Cycle How what we are is what we eat • In aerobic organisms, the citric acid cycle is an amphibolic pathway, one that serves in both catabolic and anabolic processes. • Since the citric acid does both synthesis (anabolic) and breakdown (catabolic) activities, it is called an amphibolic pathway • The citric acid cycle is amphibolic (i.e it is both anabolic and catabolic in its function). • It is said to be an AMPHIBOLIC pathway, because it functions in both degradative or catabolic and biosynthetic or anabolic reactions (amphi = both) A central metabolic pathway or amphibolic pathway is a set of reactions which permit the interconversion of several metabolites, and represents the end of the catabolism and the beginning of anabolism • The KREBS CYCLE or citric acid cycle is a series of reactions that degrades acetyl CoA to yield carbon dioxide, and energy, which is used to produce NADH, H+ and FADH. • The KREBS CYCLE connects the catabolic pathways that begin with the digestion and degradation of foods in stages 1 and 2 with the oxidation of substrates in stage 3 that generates most of the energy for ATP synthesis. • The citric acid cycle is the final common pathway in the oxidation of fuel molecules. In stage 3 of metabolism, citric acid is a final common catabolic intermediate in the form of acetylCoA. • This is why the citric acid cycle is called a central metabolic pathway. Anaplerosis and Cataplerosis Anaplerosis is a series of enzymatic reactions in which metabolic intermediates enter the citric acid cycle from the cytosol. Cataplerosis is the opposite, a process where intermediates leave the citric acid cycle and enter the cytosol. -
Exam #2 Review
Exam #2 Review Exam #2 will cover all the material that has been presented in class since Exam #1 and up through the metabolism introduction. This includes eukaryotic cell structure / function, transport, the closed system growth curve, enzymes and the introduction to metabolism. As always, it is best to begin by studying your notes and then after you feel your study is complete, take some time to look through this review. I. Eukaryotic cell structure / function A. There is a great deal of variance among eukaryotic cells - from protozoan cells to yeast cells to human cells. Fungi and protists (classically split into algae and protozoa) are eukaryotic representatives of the microbial world. B. Structure of the eukaryotic cell. 1. Cytoskeleton - provides structure and shape of cell, three components: a. Microtubules - largest element of cytoskeleton, composed of hollow cylinders of tubulin, form mitotic spindles, cilia and flagella and cell “highways”. b. Microfilaments - smallest element of cytoskeleton, composed of actin, involved in motion (pseudopod formation). c. Intermediate filaments - very stable structural element, play a supportive role, composed of proteins including keratin. Practice: Microfilaments a. are a component of the cytoskeleton. b. are long, twisted polymers of a protein called actin. c. form eukaryotic flagella. d. are made of tubulin. e. a and b f. c and d 2. Nucleus a. Bound by both an inner and outer membrane. The space between the two membranes is called the perinuclear space. The membrane has large nuclear pores through which proteins can pass (Why is this important?) b. Linear pieces of DNA are packaged by wrapping one and three quarters times around a histone octamer to form a core particle. -
Effect of Citric Acid Cycle Genetic Variants and Their Interactions With
cancers Article Effect of Citric Acid Cycle Genetic Variants and Their Interactions with Obesity, Physical Activity and Energy Intake on the Risk of Colorectal Cancer: Results from a Nested Case-Control Study in the UK Biobank Sooyoung Cho 1 , Nan Song 2,3 , Ji-Yeob Choi 2,4,5 and Aesun Shin 1,2,* 1 Department of Preventive Medicine, Seoul National University College of Medicine, Seoul 03080, Korea; [email protected] 2 Cancer Research Institute, Seoul National University, Seoul 03080, Korea; [email protected] (N.S.); [email protected] (J.-Y.C.) 3 Department of Epidemiology and Cancer Control, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA 4 Department of Biomedical Sciences, Graduate School of Seoul National University, Seoul 03080, Korea 5 Medical Research Center, Institute of Health Policy and Management, Seoul National University, Seoul 03080, Korea * Correspondence: [email protected]; Tel.: +82-2-740-8331; Fax: +82-2-747-4830 Received: 18 August 2020; Accepted: 9 October 2020; Published: 12 October 2020 Simple Summary: The citric acid cycle has a central role in the cellular energy metabolism and biosynthesis of macromolecules in the mitochondrial matrix. We identified the single nucleotide polymorphisms (SNPs) of the citrate acid cycle with colorectal cancer susceptibility in UK population. Furthermore, we found the significant interaction of SNPs in the citric acid cycle with the contributors to energy balance and SNP-SNP interactions. Our findings provide clues to the etiology in cancer development related to energy metabolism and evidence on identification of the population at high risk of colorectal cancer. -
Nutrition and Metabolism
NUTRITION AND METABOLISM Metabolism - the sum of the chemical changes that occur in the cell and involve the breakdown (catabolism) and synthesis (anabolism) of stored energy sources. Basal Metabolic Rate is dened as the rate of energy production by the body measured under a dened set of conditions which is usually at rest (physical and mental), room temperature, 12 hours after a meal. The result is produced as a percentage of a standard value which is derived from studies of normal healthy people. Measurement of the metabolic rate takes place using a method called calorimetry. This may be done directly by measuring the amount of heat produced by the body in an Atwater chamber, the metabolic rate is the amount of heat produced per hour. More commonly the metabolic rate is determined indirectly by putting people on a closed circuit breathing system, with CO2 removed by a soda lime scrubber and the rate of oxygen consumption measured by change in volume. Oxygen consumption is proportional to the metabolic rate because most of the energy in the body is derived from oxidative phosphorylation, which uses a set amount of oxygen to produce a set amount of energy. For every litre of oxygen consumed the body produces (uses) 4.82 kcals of energy. If the oxygen consumption is 250ml/min (15L/hr) then the metabolic rate is 72.3 kcals/hr. This is often further rened by dividing the gure by the body surface area which for a 70kg male is 1.73m2. This gives an average BMR of approximately 40 kcal/m2/hr. -
Biol 1020: Photosynthesis
Chapter 10: Photosynthesis Energy and Carbon Sources Electromagnetic Spectrum and Light Chloroplasts Photosynthesis Overview Light Reactions C3 Cycle Photorespiration Supplemental Carbon Fixation: C4 and CAM pathways . • List and differentiate the 4 possible groups of organisms based on how they obtain energy and useful carbon. Classification by Energy and Carbon Sources energy source chemotrophs can only get energy directly from chemical compounds phototrophs can get energy directly from light (these organisms can use chemical compounds as energy sources as well) . Classification by Energy and Carbon Sources carbon source autotrophs can fix carbon dioxide, thus they can use CO2 as a carbon source heterotrophs cannot fix CO2; they use organic molecules from other organisms as a carbon source . Classification by Energy and Carbon Sources combined, these leads to 4 possible groups: photoautotrophs – carry out photosynthesis use light energy to fix CO2 store energy in chemical bonds of organic molecules includes green plants, algae, and some bacteria photoheterotrophs – use light energy but cannot fix CO2; some nonsulfur purple bacteria chemoautotrophs – obtain energy from reduced inorganic molecules and use some of it to fix CO2; some bacteria chemoheterotrophs – use organic molecules as both carbon and energy sources dependent completely on other organisms for energy capture and carbon fixation includes all animals, all fungi, most protists, and most bacteria . • List and differentiate the 4 possible groups of -
Tricarboxylic Acid (TCA) Cycle Intermediates: Regulators of Immune Responses
life Review Tricarboxylic Acid (TCA) Cycle Intermediates: Regulators of Immune Responses Inseok Choi , Hyewon Son and Jea-Hyun Baek * School of Life Science, Handong Global University, Pohang, Gyeongbuk 37554, Korea; [email protected] (I.C.); [email protected] (H.S.) * Correspondence: [email protected]; Tel.: +82-54-260-1347 Abstract: The tricarboxylic acid cycle (TCA) is a series of chemical reactions used in aerobic organisms to generate energy via the oxidation of acetylcoenzyme A (CoA) derived from carbohydrates, fatty acids and proteins. In the eukaryotic system, the TCA cycle occurs completely in mitochondria, while the intermediates of the TCA cycle are retained inside mitochondria due to their polarity and hydrophilicity. Under cell stress conditions, mitochondria can become disrupted and release their contents, which act as danger signals in the cytosol. Of note, the TCA cycle intermediates may also leak from dysfunctioning mitochondria and regulate cellular processes. Increasing evidence shows that the metabolites of the TCA cycle are substantially involved in the regulation of immune responses. In this review, we aimed to provide a comprehensive systematic overview of the molecular mechanisms of each TCA cycle intermediate that may play key roles in regulating cellular immunity in cell stress and discuss its implication for immune activation and suppression. Keywords: Krebs cycle; tricarboxylic acid cycle; cellular immunity; immunometabolism 1. Introduction The tricarboxylic acid cycle (TCA, also known as the Krebs cycle or the citric acid Citation: Choi, I.; Son, H.; Baek, J.-H. Tricarboxylic Acid (TCA) Cycle cycle) is a series of chemical reactions used in aerobic organisms (pro- and eukaryotes) to Intermediates: Regulators of Immune generate energy via the oxidation of acetyl-coenzyme A (CoA) derived from carbohydrates, Responses. -
The Summary Equation of Cellular Respiration. the Difference Between
The summary equation of cellular respiration. The difference between fermentation and cellular respiration. The role of glycolysis in oxidizing glucose to two molecules of pyruvate. The process that brings pyruvate from the cytosol into the mitochondria and introduces it into the citric acid cycle. How the process of chemiosmosis utilizes the electrons from NADH and FADH2 to produce ATP. E flows into ecosystem as Sunlight Autotrophs transform it into chemical E O2 released as byproduct Cells use some of chemical E in organic molecules to make ATP E leaves as heat Catabolic Pathway Complex organic Simpler waste molecules products with less E Some E used to do work and dissipated as heat Introduction Respiration (15 min) Respiration: exergonic (releases E) C6H12O6 + 6O2 6H2O + 6CO2 + ATP (+ heat) Fermentation exergonic (releases E) C6H12O6 2-3 C products + ATP (small amounts) Photosynthesis: endergonic (requires E) 6H2O + 6CO2 + Light C6H12O6 + 6O2 oxidation (donor) lose e- Xe- + Y X + Ye- reduction (acceptor) gain e- Oxidation = lose e- OiLRiG or LeoGer Reduction = gain e- oxidation C6H12O6 + 6O2 6H2O + 6CO2 + ATP reduction Energy is released as electrons “fall” from organic molecules to O2 Broken down into steps: Food (Glucose) NADH ETC O2 . Coenzyme NAD+ = electron acceptor . NAD+ picks up 2e- and 2H+ NADH (stores E) . NADH carries electrons to the electron transport chain (ETC) - . ETC: transfers e to O2 to make H2O ; releases energy Generate small amount of ATP Phosphorylation: enzyme transfers a phosphate to other -
Citric Acid Cycle
CHEM464 / Medh, J.D. The Citric Acid Cycle Citric Acid Cycle: Central Role in Catabolism • Stage II of catabolism involves the conversion of carbohydrates, fats and aminoacids into acetylCoA • In aerobic organisms, citric acid cycle makes up the final stage of catabolism when acetyl CoA is completely oxidized to CO2. • Also called Krebs cycle or tricarboxylic acid (TCA) cycle. • It is a central integrative pathway that harvests chemical energy from biological fuel in the form of electrons in NADH and FADH2 (oxidation is loss of electrons). • NADH and FADH2 transfer electrons via the electron transport chain to final electron acceptor, O2, to form H2O. Entry of Pyruvate into the TCA cycle • Pyruvate is formed in the cytosol as a product of glycolysis • For entry into the TCA cycle, it has to be converted to Acetyl CoA. • Oxidation of pyruvate to acetyl CoA is catalyzed by the pyruvate dehydrogenase complex in the mitochondria • Mitochondria consist of inner and outer membranes and the matrix • Enzymes of the PDH complex and the TCA cycle (except succinate dehydrogenase) are in the matrix • Pyruvate translocase is an antiporter present in the inner mitochondrial membrane that allows entry of a molecule of pyruvate in exchange for a hydroxide ion. 1 CHEM464 / Medh, J.D. The Citric Acid Cycle The Pyruvate Dehydrogenase (PDH) complex • The PDH complex consists of 3 enzymes. They are: pyruvate dehydrogenase (E1), Dihydrolipoyl transacetylase (E2) and dihydrolipoyl dehydrogenase (E3). • It has 5 cofactors: CoASH, NAD+, lipoamide, TPP and FAD. CoASH and NAD+ participate stoichiometrically in the reaction, the other 3 cofactors have catalytic functions. -
Chapter 9 (Part 2): Glycolysis & Krebs Cycle (9.2 & 9.3)
NOTES: Chapter 9 (Part 2): Glycolysis & Krebs Cycle (9.2 & 9.3) ● CELLULAR RESPIRATION: reactions in living cells in which sugars are broken down and energy is released Mitochondria in a Liver Cell!! Glucose + oxygen carbon dioxide + water + ENERGY C6H12O6 + 6O2 6CO2 + 6H2O + energy ● Food (glucose), like fuel, is “burned” by our cells for energy; however if it is burned all at once, too much energy is released. ● So, the reaction is broken down into many small steps controlled by ENZYMES ● the energy is transferred to the bonds of ATP which stores and releases the energy in usable amounts (packets) to be used by the cell Recall: the ATP cycle -Glucose = “large denomination” ($100) -ATP = “small change” ($1) *For each molecule of glucose, the cell can make approximately 36-38 ATP. Steps of Cellular Respiration: Phase of Occurs Starts Ends # of ATP Resp. where? with? with? made cyto- Glycoly- plasm 1 2 2 sis glucose pyruvate; NADH Krebs cycle (Citric Acid Cyc) E.T.C. (Resp Chain) & oxidative phosphor Steps of Cellular Respiration: Phase of Occurs Starts Ends # of ATP Resp. where? with? with? made cyto- Glycoly- plasm 1 2 2 sis glucose pyruvate; NADH Krebs inner 2 4 CO2, cycle matrix of pyruvate NADH, 2 (Citric Acid mito- FADH2 Cyc) chondria E.T.C. (Resp Chain) & oxidative phosphor Steps of Cellular Respiration: Phase of Occurs Starts Ends # of ATP Resp. where? with? with? made cyto- Glycoly- plasm 1 2 2 sis glucose pyruvate; NADH Krebs inner 2 4 CO2, cycle matrix of pyruvate NADH, 2 (Citric Acid mito- FADH2 Cyc) chondria E.T.C. -
Pyruvate Dehydrogenase
Aerobic Metabolism I: The Citric Acid Cycle Chapter 9 Overview n Live processes - series of oxidation-reduction reactions ¨ Ingestion of proteins, carbohydrates, lipids ¨ Provide basic building blocks for major molecules ¨ Produces energy n Aerobic metabolism I ¨ Citric Acid Cycle – series of reactions that release chemical energy stored in acetyl-CoA n Acetyl-CoA derived from pyruvate From McKee and McKee, Biochemistry, 5th Edition, © 2011 Oxford University Press Chapter 9: Overview §Citric acid cycle §Two-carbon fragments oxidized to form CO2 + §NAD /FAD reduced to NADH/FADH2 §Electron transport chain §Transfer of electrons from NADH/FADH2 to electron carriers §Terminal acceptor O2 §Oxidative phosphorylation §Energy released forms proton gradient §Drives ATP synthesis Figure 9.1 Overview of Aerobic Metabolism From McKee and McKee, Biochemistry, 5th Edition, © 2011 Oxford University Press Section 9.1: Oxidation-Reduction Reactions Figure 9.3 Reduction of Pyruvate by NADH §Redox reactions – electron transfer between an electron donor (reducing agent) & electron acceptor (oxidizing agent) §Many redox reactions have both an electron (e-) and a proton (H+) transferred §Conversion of pyruvate and NADH to lactate and NAD+ (shown above) is under anaerobic conditions From McKee and McKee, Biochemistry, 5th Edition, © 2011 Oxford University Press Section 9.1: Oxidation-Reduction Reactions §Half-reactions of redox reactions Cu loses e-, electron donor Cu+ ß à Cu2+ + e- Fe gains e-, electron acceptor Fe3+ + e- ß à Fe2+ Figure 9.4 An Electrochemical -
Spontaneous Generation & Origin of Life Concepts from Antiquity to The
SIMB News News magazine of the Society for Industrial Microbiology and Biotechnology April/May/June 2019 V.69 N.2 • www.simbhq.org Spontaneous Generation & Origin of Life Concepts from Antiquity to the Present :ŽƵƌŶĂůŽĨ/ŶĚƵƐƚƌŝĂůDŝĐƌŽďŝŽůŽŐLJΘŝŽƚĞĐŚŶŽůŽŐLJ Impact Factor 3.103 The Journal of Industrial Microbiology and Biotechnology is an international journal which publishes papers in metabolic engineering & synthetic biology; biocatalysis; fermentation & cell culture; natural products discovery & biosynthesis; bioenergy/biofuels/biochemicals; environmental microbiology; biotechnology methods; applied genomics & systems biotechnology; and food biotechnology & probiotics Editor-in-Chief Ramon Gonzalez, University of South Florida, Tampa FL, USA Editors Special Issue ^LJŶƚŚĞƚŝĐŝŽůŽŐLJ; July 2018 S. Bagley, Michigan Tech, Houghton, MI, USA R. H. Baltz, CognoGen Biotech. Consult., Sarasota, FL, USA Impact Factor 3.500 T. W. Jeffries, University of Wisconsin, Madison, WI, USA 3.000 T. D. Leathers, USDA ARS, Peoria, IL, USA 2.500 M. J. López López, University of Almeria, Almeria, Spain C. D. Maranas, Pennsylvania State Univ., Univ. Park, PA, USA 2.000 2.505 2.439 2.745 2.810 3.103 S. Park, UNIST, Ulsan, Korea 1.500 J. L. Revuelta, University of Salamanca, Salamanca, Spain 1.000 B. Shen, Scripps Research Institute, Jupiter, FL, USA 500 D. K. Solaiman, USDA ARS, Wyndmoor, PA, USA Y. Tang, University of California, Los Angeles, CA, USA E. J. Vandamme, Ghent University, Ghent, Belgium H. Zhao, University of Illinois, Urbana, IL, USA 10 Most Cited Articles Published in 2016 (Data from Web of Science: October 15, 2018) Senior Author(s) Title Citations L. Katz, R. Baltz Natural product discovery: past, present, and future 103 Genetic manipulation of secondary metabolite biosynthesis for improved production in Streptomyces and R. -
Chemiosmosis Principle Versus Murburn Concept: Why Do Cells Need Oxygen? Deducing the Underpinnings of Aerobic Respiration by Mechanistic Predictability
Chemiosmosis principle versus murburn concept: Why do cells need oxygen? Deducing the underpinnings of aerobic respiration by mechanistic predictability Kelath Murali Manoj1*, Vidhu Soman2, Vivian David Jacob1, Abhinav Parashar3, Daniel Andrew Gideon4, Manish Kumar1, Afsal Manekkathodi5, Surjith Ramasamy6, Kannan Pakhirajan6 *1Satyamjayatu: The Science & Ethics Foundation, Snehatheeram, Kulappully, Shoranur-2 (PO), Kerala, India-679122. [email protected] 2Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India-110016. 3Department of Biotechnology, Vignan’s Foundation for Science, Technology & Research, Vadlamudi, Guntur, India-522213. 4Department of Biotechnology & Bioinformatics, Bishop Heber College (Autonomous), Tennur, Tiruchirappalli, India-620017. 5Photovoltaics and Thin-film Solar Cells, Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Ar-Rayyan, Qatar. 6Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India-781039. Abstract: The long-standing explanation for cellular respiration (mitochondrial oxidative phosphorylation, mOxPhos) in textbooks is proton-centric and involves the elements of Rotary ATP synthesis, Chemiosmosis principle, Proton pumps and Electron transport chain (in short, the RCPE model). Addressing certain lacunae in the RCPE model, an alternative scheme based on murburn concept was proposed in 2017 (Manoj, 2017). The new proposal is oxygen-centric in essence, and it advocates constructive roles for diffusible reactive oxygen species (DROS) in electron transfer reactions and ATP-synthesis. By the end of 2018, significant arguments and experimental evidences (in vitro, in situ, and in silico) had accumulated supporting the new mechanism. Herein, the authors compare the predictive capabilities of the two models. Theoretical concepts and expectations are detailed to differentiate the two models, and the correlations are cross-checked with the available data/information.