Ch 15 Intro-.1, .2

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  1. ·         __ are carried out by a __ that are collectively known as __ or __
    ·         __ has a coherent design containing many common motifs, which include __ and the repeated appearance of a __
    • Energy processes
    • highly integrated network of chemical reactions
    • metabolism or intermediary metabolism

    • Metabolism  
    • energy currency
    • limited number of activated intermediates
  2. ·         The __ is large, but the __ is small and the mechanisms of these reactions are usually quite simple
    ·         Fuels are __and large molecules are __step by step in a series of linked reactions called __
    ·         An energy currency common to all life forms, __, links __ with __
    • number of reactions in metabolism
    • number of kinds of reactions

    • degraded 
    • constructed 
    • metabolic pathways
    • ATP
    • energy-releasing pathways
    • energy-requiring pathways
  3. ·         The __ powers the __
    ·         Although there are many __, a limited number of types of reactions and particular intermediates are common to many pathways
    Metabolic pathways are __
    • oxidation of carbon fuels
    • formation of ATP
    • metabolic pathways
    • highly regulated
  4. ·         Living organisms need free energy for (1)__, (2) __, and (3) __
    o   The free energy used in these processes, which maintain an organism in a state that is __, is derived from the __.
    §  __, obtain the energy by trapping sun
    §  __obtain energy through the oxidation of food
    • the performance of mechanical work in muscle contraction and cellular movements
    • the active transport of molecules and ions
    • the synthesis of macromolecules and other biomolecules from simple precursors

    • far from equilibrium
    • environment

    • Photosynthetic organisms, or phototrophs
    • Chemotrophs
  5. ·         Metabolism is a __; and, their activity is coordinated by __ in which __ are predominant
    linked series of chemical reactions that begins with a particular molecule and converts it into some other molecule or molecules in a carefully defined fashion, which are interdependent

    • exquisitely sensitive means of communication
    • allosteric enzymes
  6. ·         Metabolic processes can be those that __ and those that __—__ and __ (if bothà __)
    ·         An important general principle of metabolism is that __ and __ are almost always distinct. This separation is necessary for energetic reasons and facilitates __
    convert energy from fuels into biologically useful forms

    require inputs of energy to proceed

    catabolic and anabolic


    • biosynthetic and degradative pathways
    • control of metabolism
  7. ·         A pathway must have specific __ and its entire set of reactions that constitute the pathway must be __
    o   A specific reaction will yield only __ or __
    • individual reactions
    • thermodynamically favored
    • one particular product
    • set of products from its reactants
  8. ·         dG depends on the __ and on their __
    ·         The overall free-energy change for a chemically coupled series of reactions is equal to the __. A thermodynamically unfavorable reaction can be driven by a __ 
    • nature of the reactants and products
    • concentrations

    • sum of the free-energy changes of the individual steps
    • thermodynamically favorable reaction to which it is coupled
  9. ·         The common energy source is __, which food is oxidized to. It acts as the __ in most __; and most of catabolism consists of __ such as carbs and fats and __
    ·         The active form of ATP is usually a complex of __with __ or __

    • ATP
    • free-energy donor
    • energy-requiring processes
    • reactions that extract energy from fuels
    • convert it into ATP
    • ATP 
    • Mg2+ or Mn2+
  10. o   ATP is an energy-rich molecule because of what--> can release energy by __
    ·         The precise dGo’ for these reactions depends on the __ and on the __. Under typical cellular concentrations, the actual dG for these hydrolyses is about –50 kJ mol-1.
    its triphosphate unit contains two phosphoanhydride bonds

    hydrolysis to ADP and Pi or AMP and PPi (called pyrophosphate)

    ionic strength of the medium

    concentrations of Mg2+ and other metal ions
  11. ·         The free energy liberated in the __ is harnessed to drive reactions that require an __. ATP is formed from __ and __ when fuel molecules are __ or __. This __ is the fundamental mode of __ in biological systems
    • hydrolysis of ATP
    • input of free energy
    • ADP and inorganic phosphate
    • oxidized or light is trapped
    • ATP-ADP cycle
    • energy exchange
  12. ·         Enzymes catalyze the __. The phosphorylation of nucleoside monophosphates is catalyzed by a __. The phosphorylation of nucleoside diphosphates is catalyzed by __, an enzyme with broad specificity
    transfer of the terminal phosphoryl group from one nucleotide to another

    • nucleoside monophosphates
    • family of nucleoside monophosphate kinases
    • nucleoside diphosphate kinase
  13. ·         ATP can make an unfavorable reaction occur by __; it can be an __
    o   Cells maintain a high level of ATP by using __ as sources of __
    o   In the cell, the hydrolysis of ATP in a coupled reaction changes the __ by a very large factor. The hydrolysis of n ATP molecules changes the __ (or sequence of reactions) by a large factor.
    o   This can occur for __, __, etc. 
    • coupling the reaction to ATP hydrolysis
    • energy-coupling agent
    • oxidizable substrates or light
    • free energy
    • equilibrium ratio of products to reactants
    • equilibrium ratio of a coupled reaction
    • active and inactive enzymes, molecular motors, concentrations of ions inside and outside
  14. ·         The high phosphoryl transfer potential of ATP can be explained by __. Because dGo’ depends on the __, ATP and product structures must be examined. This reveals three important factors, which are __?
    • features of ATP structure
    • difference in free energies of products and reactants

    • resonance stabilization
    • electrostatic repulsion
    • stabilization due to hydration
  15. REsonance stabilization
    ADP and Pi have greater resonance stabilization than does ATP. Orthophosphate has a number of resonance forms of similar energy, whereas the gamma phosphoryl group of ATP has a smaller number
  16. Electrostatic repulsion
    At pH 7, the triphosphate unit of ATP carries about four negative charges. These charges repel one another because they are in close proximity. The repulsion between them is reduced when ATP is hydrolyzed 
  17. Stabilization due to hydration
    o   more water can bind more effectively to ADP and Pi than can bind to the phosphoanhydride part of ATP, stabilizing the ADP and Pi
  18. ·         The phosphate bonds in ATP are high-energy bonds in the sense that __
    ·         ATP is not the only compound with a high __; there is also __(3)__
    • much free energy is released when they are hydrolyzed
    • phosphoryl-transfer potential
    • PEP, 1,3-BPG, creatine phosphate
  19. o   PEP can do what? This transfer is one of the ways in which __
    §  It is significant that ATP has a __ that is __among the biologically important phosphorylated molecules. This intermediate position enables ATP to __
    • transfer its phosphoryl group to ADP to form ATP
    • ATP is generated in the breakdown of sugars
    • phosphoryl-transfer potential
    • intermediate 
    • function efficiently as a carrier of phosphoryl groups
  20. ·         Because the amount of ATP in a muscle allows __, creatine phosphate serves as a __ that can be readily transferred to __. This is catalyzed by __
    ·         In resting muscle, typical concentrations of metabolites are [ATP]= __ mM, [ADP]=__ mM, [creatine phosphate]= __mM, and [creatine]= __mM
    • contraction for less than a second
    • reservoir of high-potential phosphoryl groups
    • ADP for regeneration of ATP
    • creatine kinase
    • 4
    • 0.013
    • 25 
    • 13
  21. o   Because of its abundance and high phosphoryl-transfer potential relative to that of ATP, creatine phosphate is a __; and creatine phosphate is the major source of __ for a runner during the first four seconds of a 100-meter spring
    §  After the creatine phosphate pool is depleted, ATP must be generated through __
    • highly effective phosphoryl buffer
    • phosphoryl groups for ATP regeneration 
    • metabolism
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Ch 15 Intro-.1, .2
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