Human Physiology 04

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NursyDaisy
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100715
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Human Physiology 04
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2011-10-12 11:40:40
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Human Physiology
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Enzymes and Energy
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  1. What are proteins that function as biological catalysts?
    enzymes
  2. What are RNA molecules that function as biological catalyst?
    ribozymes
  3. List the three characteristics of a catalyst.
    • Increases the rate of a reaction.
    • Is not itself changed at the end of the reaction.
    • Does not change the nature of the reaction or its final result.
  4. What is the amount of energy required for a reaction to occur?
    activation energy
  5. What effect to enzymes have on the activation energy of a reaction?
    They lower it
  6. Why are enzymes essential to life?
    They make reactions occur at a rate that is fast enough to sustain life.
  7. What part of an enzyme takes part in catalyzing a reaaction?
    the active site
  8. What are the reactant molecules on which an enzyme works?
    the substrate
  9. What model of action describes how an enzyme and its substrate interact?
    the lock-and-key model
  10. What model describes how an enzyme changes its configuration to fit together with its substrate?
    the induced-fit model
  11. The temporary union of an enzyme and its substrate is referred to as what?
    the enzyme-substrate complex
  12. What molecules are the result of the enzyme-substrate complex?
    the products
  13. With the except of enzymes named before the establishment of international nomenclature, what suffix ends the names of all enzymes?
    -ase
  14. How are classes of enzymes named?
    according to their activity or job category
  15. What are enzymes that promote hydrolysis?
    hydrolases
  16. What are enzymes that catalyze the removal of phosphate groups?
    phosphatases
  17. What are enzymes that catalyze dehydration synthesis?
    synthases and synthetases
  18. What are enzymes that remove hydrogen atoms from their substrates?
    dehydrogenases
  19. What are enzymes that add a phosphate group to particular molecules?
    kinases
  20. What are enzymes which rearrange atoms within their substrate molecules to form structural isomers, such as glucose and fructose?
    isomerases
  21. Different organs may have different ìmodelsî of the same enzyme that differ in one or a few amino acids. What are these different models called?
    isoenzymes
  22. Within the temperature range from 0 degrees Celsius to 37 degrees Celsius, what happens to the activity of an enzyme as the temperature rises?
    activity increases
  23. What happens to the activity of enzymes within the human body as the temperature rises above 37 degrees Celsius?
    it decreases
  24. What is the narrow range of pH within which an enzyme exhibits its peak activity?
    the pH optimum
  25. What happens to the activity of an enzyme if the pH is not with the pH optimum for that enzyme?
    it decreases
  26. Why does the activity of an enzyme decrease it the pH is not within its optimum range?
    the configuration of the enzyme changes
  27. What are inorganic substances which are necessary for an enzyme to function properly?
    cofactors
  28. What are organic molecules that are necessary for enzymes to function properly?
    coenzymes
  29. What are inactive, precursor forms of enzymes?
    zymogens
  30. What is the process in which a phosphate group is added to a molecule?
    phosphorylation
  31. What is the process in which a phosphate group is removed from a molecule?
    dephosphorylation
  32. At any given level of enzyme concentration, the rate of product formation will increase as the substrate concentration increases. When the relationship between the substrate concentration and the reaction rate reaches a plateau, what has happened to the enzyme?
    It has been saturated
  33. Some enzyme reactions are reversible. What principle states that the reaction will be driven from the side of the reaction where the concentration is the highest?
    law of mass action
  34. What is a sequence of enzymatic reactions that begins with an initial substrate, progresses through a number of intermediates, and ends with a final product?
    a metabolic pathway
  35. What is a form of negative feedback which prevents the over accumulation of the end product of a metabolic pathway?
    end-product inhibition
  36. What mechanism occurs when the end product of a metabolic pathway combines with a part of an enzyme other than the active site to inhibit the pathway.
    allosteric inhibition
  37. What is an inherited defect in one of the genes for an enzyme that is part of a metabolic pathway?
    an inborn error of metabolism
  38. What is the flow of energy through living systems?
    bioenergetics
  39. What principle states that energy can be neither created nor destroyed, but it can be transformed from one form to another?
    the first law of thermodynamics
  40. What is the degree of disorganization of a systems total energy?
    entropy
  41. What principle state that the amount of entropy increases with each energy transformation?
    the second law of thermodynamics
  42. As entropy increases, what happens to the amount of energy available to do work?
    It decreases
  43. What are chemical reactions that require an input of energy?
    endergonic reactions
  44. What type of reactions release energy as they proceed?
    exergonic reactions
  45. What is the amount of heat required to raise the temperature of one gram (one cubic centimeter or one milliliter) one degree Celsius?
    a calorie
  46. What unit of measure is usually used for foods?
    the kilocalorie (Calorie)
  47. Coupled reactions involve what two types of reactions?
    exergonic and endergonic
  48. The energy released by most exergonic reactions in the cell, either directly, or indirectly , drive the formation of what molecule?
    adenosine triphosphate
  49. What is the full term for ATP?
    adenosine triphosphate
  50. What is the universal energy carrier in living systems?
    adenosine triphosphate
  51. What are the three things ATP is used for?
    • Biomechanical movement
    • Transportation
    • To make reactions go
  52. What is the reduction of a molecule?
    the gaining of electrons
  53. What is the oxidation of a molecule?
    the loss of electrons
  54. What is a molecule that donates electrons to another?
    a reducing agent
  55. What is a molecule that accepts electrons?
    an oxidizing agent
  56. Name two molecules that are important in transferring hydrogen from one molecule to another. They are coenzymes that act as hydrogen carriers.
    • nicotinamide adenine dinucleotide (NAD)
    • flavin adenine dinucleotide (FAD)
  57. What are the reduced forms of NAD and FAD?
    NADH + H+ and FADH2

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