BIO-1120: Chapter 6

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  1. Metabolism
    the totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism
  2. Metabolic Pathway
    a series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathway)
  3. Catabolic Pathway
    a metabolic pathway that releases energy by breaking down complex molecules to simpler molecules
  4. Anabolic Pathway
    a metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules
  5. Bioenergetics
    (1) the overall flow and transformation of energy in an organism; (2) the study of how energy flows through organisms
  6. Energy
    the capacity to cause change, especially to do work (to move matter against an opposing force)
  7. Kinetic Energy
    the energy associated with the relative motion of objects; moving matter can perform work by imparting motion to other matter
  8. Thermal Energy
    kinetic energy due to the random motion of atoms and molecules; energy in its most random form
  9. Heat
    thermal energy in transfer from one body of matter to another
  10. Potential Energy
    the energy that matter possesses as a result of its location or spatial arrangement (structure)
  11. Chemical Energy
    energy available in molecules for release in a chemical reaction; a form of potential energy
  12. Thermodynamics
    a chemical agent that selectively increases the rate of a reaction without being consumed by the reaction
  13. First Law of Thermodynamics
    the principle of conservation of energy: Energy can be transferred and transformed, but it cannot be created or destroyed
  14. Entropy
    a measure of disorder, or randomness
  15. Second Law of Thermodynamics
    the principle stating that every energy transfer or transformation increases the entropy of the universe; usable forms of energy are at least partly converted to heat
  16. Spontaneous Process
    a process that occurs without an overall input of energy; a process that is energetically favorable
  17. Free Energy
    the portion of a biological system's energy that can perform work when temperature and pressure are uniform throughout the system; the change in free energy of a system (ΔG) is calculated by the equation ΔG = ΔH - TΔS. where ΔH is the change in enthalpy (in biological systems, equivalent to total energy), ΔT is the absolute temperature, and ΔS is the change in entropy
  18. Exergonic Reaction
    a spontaneous chemical reaction in which there is a net release of free energy
  19. Endergonic Reaction
    a non-spontaneous chemical reaction in which free energy is absorbed from the surroundings
  20. Energy Coupling
    in cellular metabolism; the use of energy released from an exergonic reaction to drive an endergonic reaction
  21. ATP (adenosine triphosphate)
    an adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed; this energy is used to drive endergonic reactions in cells
  22. Phosphorylated Intermediate
    a molecule (often a reactant) with a phosphate group covalently bound to it, making it more reactive (less stable) than the unphosphorylated molecule
  23. Enzyme
    a macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction; most enzymes are proteins
  24. Catalyst
    a chemical agent that selectively increases the rate of a reaction without being consumed by the reaction
  25. Activation Energy
    the amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation
  26. Substrate
    the reactant n which an enzyme works
  27. Enzyme-Substrate Complex
    a temporary complex formed when an enzyme binds to its substrate molecule(s)
  28. Active Site
    the specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs
  29. Induced Fit
    caused by entry of the substrate, the change in shape of the active site of an enzyme so that is binds more snugly to the substrate
  30. Cofactors
    any nonprotein molecule or ion that is required for the proper functioning of an enzyme; cofactors can be permanently bound t the active site or may bind loosely and reversibly, along with the substrate, during catalysis
  31. Coenzyme
    an organic molecule serving as a cofactor; most vitamins function as coenzymes in metabolic reactions
  32. Competitive Inhibitors
    a substance that reduces the activity of an enzyme by entering the active site in place of the substrate, whose structure it mimics
  33. Noncompetitive Inhibitors
    a substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing the enzyme's shape so that the active site no longer effectively catalyzes the conversion of substrate to product
  34. Allosteric Regulation
    the binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site
  35. Cooperativity
    a kind of allosteric regulation whereby a shape change in one subunit of a protein caused by substrate binding is transmitted to all other subunits, facilitating binding of additional substrate molecules to those subunits
  36. Feedback Inhibition
    a method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway
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BIO-1120: Chapter 6
2014-12-20 18:36:09
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