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24 Biological Energy Transfer Cellular Respiration Involves the Stepwise Transfer of Energy and Electrons
contents Principles of Biology 24 Biological Energy Transfer Cellular respiration involves the stepwise transfer of energy and electrons. Large-scale municipal composting. The steam emitted from the compost as it is being turned is evidence of trillions of microorganisms performing cellular respiration, breaking down molecules in the compost and generating energy, some in the form of heat. Nancy J. Pierce/Science Source. Topics Covered in this Module How Do Organisms Obtain Energy? Redox Reactions An Outline of the Stages in Cellular Respiration Major Objectives of this Module Describe the relationships among photosynthesis, respiration, producers, and consumers. Explain how reduction-oxidation (redox) reactions work. Describe how aerobic cellular respiration breaks down fuel molecules and releases energy for cellular work. page 121 of 989 4 pages left in this module contents Principles of Biology 24 Biological Energy Transfer How Do Organisms Obtain Energy? No matter how wealthy you become in life, you will always work for a living. That is, your cells will always be working to keep you alive. From synthesizing proteins to producing gametes to chasing down prey, living cells are constantly at work, and all that work requires energy. Where does that energy come from? Ultimately it comes from our Sun as light energy. Energy flows through all living systems. Plants, algae, and photosynthetic bacteria use energy from sunlight to generate sugar molecules through the process of photosynthesis. Such organisms, known as photoautotrophic producers, convert the radiant energy of sunlight into chemical energy that they store in sugars and other organic compounds. Other organisms, termed heterotrophic consumers, must acquire the chemical energy they need by ingesting or absorbing organic molecules from other organisms. -
Detection and Formation Scenario of Citric Acid, Pyruvic Acid, and Other Possible Metabolism Precursors in Carbonaceous Meteorites
Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites George Coopera,1, Chris Reeda, Dang Nguyena, Malika Cartera, and Yi Wangb aExobiology Branch, Space Science Division, National Aeronautics and Space Administration-Ames Research Center, Moffett Field, CA 94035; and bDevelopment, Planning, Research, and Analysis/ZymaX Forensics Isotope, 600 South Andreasen Drive, Suite B, Escondido, CA 92029 Edited by David Deamer, University of California, Santa Cruz, CA, and accepted by the Editorial Board July 1, 2011 (received for review April 12, 2011) Carbonaceous meteorites deliver a variety of organic compounds chained three-carbon (3C) pyruvic acid through the eight-carbon to Earth that may have played a role in the origin and/or evolution (8C) 7-oxooctanoic acid and the branched 6C acid, 3-methyl- of biochemical pathways. Some apparently ancient and critical 4-oxopentanoic acid (β-methyl levulinic acid), Fig. 1, Table S1. metabolic processes require several compounds, some of which 2-methyl-4-oxopenanoic acid (α-methyl levulinic acid) is tenta- are relatively labile such as keto acids. Therefore, a prebiotic setting tively identified (i.e., identified by mass spectral interpretation for any such individual process would have required either a only). As a group, these keto acids are relatively unusual in that continuous distant source for the entire suite of intact precursor the ketone carbon is located in a terminal-acetyl group rather molecules and/or an energetic and compact local synthesis, parti- than at the second carbon as in most of the more biologically cularly of the more fragile members. -
Aqueous Phase Photochemistry of Α-Keto Acids As a Function of Ph
Aqueous Phase Photochemistry of α-Keto Acids as a Function of pH Michael Ryan Dooley Department of Chemistry and Biochemistry University of Colorado at Boulder March 21 2017 Advisor: Dr. Veronica Vaida, Department of Chemistry and Biochemistry Committee: Dr. Veronica Vaida, Department of Chemistry and Biochemistry Dr. Robert Parson, Department of Chemistry and Biochemistry Dr. Chris Bowman, Department of Chemical and Biological Engineering 1 Tables of Contents Abstract……………………………………………………………………………………..page 2 Introduction…………………………………………………………………………………page 2 Experimental Methods………………………………………………………………….…..page 9 Materials……………………………………………………………………….……page 9 Titration – Debye-Huckel Extended Method……………………………………….page 9 Photolysis of Pyruvic Acid……………………………...…………………………page 11 Ultraviolet-Visible Spectroscopy……………………………………….…………page 12 1HNMR…………………………………………………………………………….page 12 Electrospray Ionization Mass Spectrometry……………..………………………...page 13 Results and Discussion…………………………………………...………………..………page 13 Determination of Acid Dissociation Constants…………………………………….page 13 Dependence of Keto-Diol Ratio on pH…………………………………………….page 16 Dark Processing of Pre-Photolysis Solutions…………………………………..….page 18 Photolysis of Pyruvic Acid………………………………….……………………..page 21 Conclusions and Future Directions…………...…………………………………………....page 27 References…………………………………………………………………….……………page 29 2 Abstract α-Keto acids react in solution in the presence of sunlight to form complex organic oligomers that can contribute to the formation of organic atmospheric aerosols. -
Photosynthesis and Respiration
18 Photosynthesis and Respiration ATP is the energy currency of the cell Goal To understand how energy from sunlight is harnessed to Cells need to carry out many reactions that are energetically unfavorable. generate chemical energy by photosynthesis and You have seen some examples of these non-spontaneous reactions in respiration. earlier chapters: the synthesis of nucleic acids and proteins from their corresponding nucleotide and amino acid building blocks and the transport Objectives of certain ions against concentration gradients across a membrane. In many cases, unfavorable reactions like these are coupled to the hydrolysis of ATP After this chapter, you should be able to: in order to make them energetically favorable under cellular conditions; we • Explain the concepts of oxidation and have learned that for these reactions the free energy released in breaking reduction. the phosphodiester bonds in ATP exceeds the energy consumed by the • Explain how light energy generates an uphill reaction such that the sum of the free energy of the two reactions is electrochemical gradient. negative (ΔG < 0). To perform these reactions, cells must then have a way • Explain how an electrochemical of generating ATP efficiently so that a sufficient supply is always available. gradient generates chemical energy. The amount of ATP used by a mammalian cell has been estimated to be on the order of 109 molecules per second. In other words, ATP is the principal • Explain how chemical energy is harnessed to fix carbon dioxide. energy currency of the cell. • Explain how glucose is used to generate How does the cell produce enough ATP to sustain life and what is the source ATP anaerobically. -
Transamination What Is Transamination? Subhadipa 2020 • Important Method of Nitrogen Metabolism of Amino Acids
Subhadipa 2020 Transamination What is Transamination? Subhadipa 2020 • Important method of nitrogen metabolism of amino acids. • Transamination is the transfer of an amine group from an amino acid to a keto acid (amino acid without an amine group), thus creating a new amino acid and keto acid. • Transamination reactions combine reversible amination and deamination, and they mediate redistribution of amino groups among amino acids. • Transaminases (aminotransferases) are widely distributed in human tissues and are particularly active in heart muscle, liver, skeletal muscle, and kidney. • The general reaction of transamination is: Concerned enzyme • The reaction is catalyzed by transaminase or amino transferase. • Enzymes act on L-amino acid but not on D-isomers. • They occur both mitochondria and cytosol as separate enzyme. • There are many transferases, each acts on a particular amino acid and a particular keto acid. Amino and keto acid • All naturally occurring amino acids undergo transamination. • Exceptions include basic amino acids lysine, hydroxyl amino acids, serine and threonine and heterocyclic amino acids proline and hydroxyl-proline. • Keto acids like pyruvic acid, oxaloacetic acid and α- ketoglutaric acid are commonly involved. • Glyoxylate and glutamic γ semialdehyde may also act as amino- receptors in transamination. E-PLP Complex Subhadipa 2020 All transaminase reactions have the same mechanism and use pyridoxal phosphate (a derivative of vitamin B6). Pyridoxal phosphate is linked to the enzyme by formation of a Schiff base between its aldehyde group and the ε-amino group of a specific lysyl residue at the active site and held noncovalently through its positively charged nitrogen atom and the negatively charged phosphate group. -
Chem 352 - Lecture 10, Part II Citric Acid Cycle
Chem 352 - Lecture 10, Part II Citric Acid Cycle Question for the Day: One of the observations that led Hans Krebs to discover the citric acid cycle, was that dicarboxylic acids, such as fumarate and succinate, had a catalytic effect on the oxidation of glucose to CO2 and H2O by muscle tissue. Explain his observation. Introduction Chem 352, Lecture 10, Part II - Citric Acid Cycle 2 Introduction 13.1 Overview of Pyruvate Oxidation and the Citric Acid Cycle 13.2 Pyruvate Oxidation: A Major Entry Route for Carbon in the Citric Acid Cycle 13.3 The Citric Acid Cycle 13.4 Stoichiometry and Energetics of the Citric Acid Cycle 13.5 Regulation of Pyruvate Dehydrogenase and the Citric Acid Cycle 13.8 Anapleoritic Sequences: The Need to Replace Cycle Intermediates. 13.9 The Glyoxylate Cycle: An Anabolic Variant of the Citric Acid Cycle Chem 352, Lecture 10, Part II - Citric Acid Cycle 2 Introduction Chem 352, Lecture 10, Part II - Citric Acid Cycle 3 Introduction Chem 352, Lecture 10, Part II - Citric Acid Cycle 3 13.1 Overview of Pyruvate Oxidation and the Citric Acid Cycle Overview Chem 352, Lecture 10, Part II - Citric Acid Cycle 5 Overview The citric acid cycle has both catabolic and anabolic functions. • Catabolic - Oxidizes the 2-carbon acetyl group to CO2 and produces reduced nucleotides (NADH + H+ and FADH2) Chem 352, Lecture 10, Part II - Citric Acid Cycle 5 Overview The citric acid cycle has both catabolic and anabolic functions. • Catabolic - Oxidizes the 2-carbon acetyl group to CO2 and produces reduced nucleotides (NADH + H+ and FADH2) • Anabolic - The citric acid cycle intermediates serve as starting material for the biosynthesis of amino acids, heme groups, glucose, et al. -
Is There a Role for Ketoacid Supplements in the Management of CKD? Anuja P
Perspective Is There a Role for Ketoacid Supplements in the Management of CKD? Anuja P. Shah, MD,1 Kamyar Kalantar-Zadeh, MD, PhD,2 and Joel D. Kopple, MD1,3 Ketoacid (KA) analogues of essential amino acids (EAAs) provide several potential advantages for people with advanced chronic kidney disease (CKD). Because KAs lack the amino group bound to the a carbon of an amino acid, they can be converted to their respective amino acids without providing additional nitrogen. It has been well established that a diet with 0.3 to 0.4 g of protein per kilogram per day that is supplemented with KAs and EAAs reduces the generation of potentially toxic metabolic products, as well as the burden of potassium, phosphorus, and possibly sodium, while still providing calcium. These KA/EAA-supplemented very-low-protein diets (VLPDs) can maintain good nutrition, but the appropriate dose of the KA/EAA supplement has not been established. Thus, a KA/EAA dose-response study for good nutrition clearly is needed. Similarly, the composition of the KA/EAA supplement needs to be reexamined; for example, some KA/EAA preparations contain neither the EAA phenylalanine nor its analogue. Indications concerning when to inaugurate a KA/EAA- supplemented VLPD therapy also are unclear. Evidence strongly suggests that these diets can delay the need for maintenance dialysis therapy, but whether they slow the loss of glomerular filtration rate in patients with CKD is less clear, particularly in this era of more vigorous blood pressure control and use of angiotensin/ aldosterone blockade. Some clinicians prescribe KA/EAA supplements for patients with CKD or treated with maintenance dialysis, but with diets that have much higher protein levels than the VLPDs in which these supplements have been studied. -
University of Groningen Exploring the Cofactor-Binding and Biocatalytic
University of Groningen Exploring the cofactor-binding and biocatalytic properties of flavin-containing enzymes Kopacz, Malgorzata IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2014 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Kopacz, M. (2014). Exploring the cofactor-binding and biocatalytic properties of flavin-containing enzymes. Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license. More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne- amendment. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 29-09-2021 Exploring the cofactor-binding and biocatalytic properties of flavin-containing enzymes Małgorzata M. Kopacz The research described in this thesis was carried out in the research group Molecular Enzymology of the Groningen Biomolecular Sciences and Biotechnology Institute (GBB), according to the requirements of the Graduate School of Science, Faculty of Mathematics and Natural Sciences. -
Amino Acid Catabolism
Amino Acid Catabolism • Dietary Proteins • Turnover of Protein • Cellular protein • Deamination • Urea cycle • Carbon skeletons of amino acids Amino Acid Metabolism •Metabolism of the 20 common amino acids is considered from the origins and fates of their: (1) Nitrogen atoms (2) Carbon skeletons •For mammals: Essential amino acids must be obtained from diet Nonessential amino acids - can be synthesized Amino Acid Catabolism • Amino acids from degraded proteins or from diet can be used for the biosynthesis of new proteins • During starvation proteins are degraded to amino acids to support glucose formation • First step is often removal of the α-amino group • Carbon chains are altered for entry into central pathways of carbon metabolism Dietary Proteins • Digested in intestine • by peptidases • transport of amino acids • active transport coupled with Na+ Protein Turnover • Proteins are continuously synthesized and degraded (turnover) (half-lives minutes to weeks) • Lysosomal hydrolysis degrades some proteins • Some proteins are targeted for degradation by a covalent attachment (through lysine residues) of ubiquitin (C terminus) • Proteasome hydrolyzes ubiquitinated proteins Turnover of Protein • Cellular protein • Proteasome degrades protein with Ub tags • T 1/2 determined by amino terminus residue • stable: ala, pro, gly, met greater than 20h • unstable: arg, lys, his, phe 2-30 min Ubibiquitin • Ubiquitin protein, 8.5 kD • highly conserved in yeast/humans • carboxy terminal attaches to ε-lysine amino group • Chains of 4 or more Ub molecules -
Differentiating the Roles of Redox-Active Cysteine Residues in Plasmodium Falciparum Thioredoxin Reductase by Using a "Seleno Effect"
University of Vermont ScholarWorks @ UVM UVM Honors College Senior Theses Undergraduate Theses 2015 Differentiating the Roles of Redox-Active Cysteine Residues in Plasmodium falciparum Thioredoxin Reductase by using a "Seleno Effect" John P. O'Keefe Follow this and additional works at: https://scholarworks.uvm.edu/hcoltheses Recommended Citation O'Keefe, John P., "Differentiating the Roles of Redox-Active Cysteine Residues in Plasmodium falciparum Thioredoxin Reductase by using a "Seleno Effect"" (2015). UVM Honors College Senior Theses. 73. https://scholarworks.uvm.edu/hcoltheses/73 This Honors College Thesis is brought to you for free and open access by the Undergraduate Theses at ScholarWorks @ UVM. It has been accepted for inclusion in UVM Honors College Senior Theses by an authorized administrator of ScholarWorks @ UVM. For more information, please contact [email protected]. Differentiating the Roles of Redox-Active Cysteine Residues in Plasmodium falciparum Thioredoxin Reductase by using a "Seleno Effect" John O’Keefe1 1Department of Biochemistry, University of Vermont, College of Medicine, 89 Beaumont Avenue, Given Building Room B413, Burlington, Vermont 05405, United States 2 ABSTRACT The purpose of my research is to determine if the substitution of selenium for sulfur will cause rate acceleration of the thiol-disulfide exchange reaction in the C-terminal redox center of Plasmodium falciparum thioredoxin reductase (PfTR) in a position specific manner. P. falciparum is the protist that causes most serious form of malaria and is responsible for the majority of malaria related deaths. While mammalian thioredoxin reductase (mTR) contains selenium in its C-terminal redox center, which accelerates the rate of reaction, PfTR functions in the absence of selenium. -
Synthesis and Redox Behavior of Flavin Mononucleotide
Published on Web 12/15/2007 Synthesis and Redox Behavior of Flavin Mononucleotide-Functionalized Single-Walled Carbon Nanotubes Sang-Yong Ju and Fotios Papadimitrakopoulos* Nanomaterials Optoelectronics Laboratory (NOEL), Polymer Program, Department of Chemistry, Institute of Materials Science, UniVersity of Connecticut, Storrs, Connecticut 06269-3136 Received August 31, 2007; E-mail: [email protected] Abstract: In this contribution, we describe the synthesis and covalent attachment of an analogue of the flavin mononucleotide (FMN) cofactor onto carboxylic functionalities of single-walled carbon nanotubes (SWNTs). The synthesis of FMN derivative (12) was possible by coupling flavin H-phosphonate (9) with an aliphatic alcohol, using a previously unreported N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydro- chloride coupling. We found that the flavin moiety of 12-SWNT shows a strong π-π interaction with the nanotube side-walls. This leads to a collapsed FMN configuration that quenches flavin photoluminescence (PL). The treatment of 12-SWNT with sodium dodecyl sulfate (SDS) overcomes this strong nanotube/ isoalloxazine interaction and restores the FMN into extended conformation that recovers its luminescence. In addition, redox cycling as well as extended sonication were proven capable to temporally restore PL as well. Cyclic voltammetry of FMN onto SWNT forests indicated profound differences for the extended and collapsed FMN configurations in relation to oxygenated nanotube functionalities that act as mediators. These findings -
Deazaflavins As Photocatalysts for the Direct Reductive Regeneration of Flavoenzymes Van Schie, M
Delft University of Technology Deazaflavins as photocatalysts for the direct reductive regeneration of flavoenzymes van Schie, M. M.C.H.; Younes, S. H.H.; Rauch, M. C.R.; Pesic, M.; Paul, C. E.; Arends, I. W.C.E.; Hollmann, F. DOI 10.1016/j.mcat.2018.04.015 Publication date 2018 Document Version Final published version Published in Molecular Catalysis Citation (APA) van Schie, M. M. C. H., Younes, S. H. H., Rauch, M. C. R., Pesic, M., Paul, C. E., Arends, I. W. C. E., & Hollmann, F. (2018). Deazaflavins as photocatalysts for the direct reductive regeneration of flavoenzymes. Molecular Catalysis, 452, 277-283. https://doi.org/10.1016/j.mcat.2018.04.015 Important note To cite this publication, please use the final published version (if applicable). Please check the document version above. Copyright Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons. Takedown policy Please contact us and provide details if you believe this document breaches copyrights. We will remove access to the work immediately and investigate your claim. This work is downloaded from Delft University of Technology. For technical reasons the number of authors shown on this cover page is limited to a maximum of 10. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.