10 Principles Of Bioenergetics

12 Questions | Total Attempts: 237

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Biochemistry Quizzes & Trivia

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Questions and Answers
  • 1. 
    Which is INCORRECT?  Energy is required by cells for:
    • A. 

      Transport of molecules or ions against a concentration gradient

    • B. 

      Synthesis of new chemical bonds

    • C. 

      Maintenance of body temperature

    • D. 

      Mechanical movement

    • E. 

      Hydrolysis of a molecule during an exothermic reaction

  • 2. 
    Which statement about catabolic reactions is true?
    • A. 

      Catabolic reactions are degradative and are generally exergonic

    • B. 

      Catabolic reactions are part of pathways responsible for synthesis for new chemical bonds

    • C. 

      Catabolic reactions generally have free enthalpy values close to zero and standard free energy values less than zero

    • D. 

      Catabolic reactions occur primarily in catabolic organisms

    • E. 

      Catabolic reactions oppose the second law of thermodynamics

  • 3. 
    Which is NOT a mechanism for regulating metabolic pathways?
    • A. 

      Control of intracellular substrate concentration

    • B. 

      Control of allosteric enzymes by inhibitors and activators

    • C. 

      Control of cell temperature

    • D. 

      Control of amount of enzymes

    • E. 

      Control of enzymes through signalling substances (e.g. hormones)

  • 4. 
    Reciprocal regulation refers to:
    • A. 

      The division of energy from the catalytic pathway by the anabolic pathway

    • B. 

      The opposite reaction type that is being referred to

    • C. 

      The ability of cells to simultaneously activate anabolic and catabolic reactions

    • D. 

      The ability of cells to simultaneously inactive anabolic and catabolic reactions

    • E. 

      Activation of one pathway, while suppressing the opposite pathway

  • 5. 
    If the ΔG'° of the reactions A → B is +20kJ/mol, under standard conditions the reaction:
    • A. 

      Will proceed spontaneously from right to left

    • B. 

      Will proceed spontaneously from left to right

    • C. 

      Will never reach equilbrium

    • D. 

      Will proceed to equilibrium at a rapid rate

    • E. 

      Is currently at equilibrium

  • 6. 
    If the ΔG'° of the reaction A → B is -100 kJ/mol, under standard conditions the reaction:
    • A. 

      Is at equilbirum

    • B. 

      Will never reach equilibrium

    • C. 

      Will not occur spontaneously

    • D. 

      Will proceed at a rapid rate

    • E. 

      Will proceed spontaneously from left to right

  • 7. 
    Which is NOT true about the following reactions?A → B   ΔG = +20 kJ/mol = reaction 1C → D   ΔG = –30 kJ/mol = reaction 2 A + C → B + D = reaction 3 
    • A. 

      Reaction 1 will proceed from right to left

    • B. 

      Reaction 2 will proceed from left to right

    • C. 

      Reaction 3, the sum of reaction 1 and 2, will occur spontaneously with overall free energy of –10 kJ/mol

    • D. 

      Reaction 1 will not proceed from left to right unless an enzyme is present

    • E. 

      Reaction 2 will proceed spontaneously

  • 8. 
    Given the following information, calculate the actual free energy of the below reaction. A → B;  Keq = 10; concentration in the cell of A = 0.2 M; B = 0.05 M; R = 8.315 J/mol.K; T = 298 K?
    • A. 

      -9.1 kJ/mol

    • B. 

      -15.8 kJ/mol

    • C. 

      -200.2 kJ/mol

    • D. 

      +22.5 kJ/mol

    • E. 

      0 kJ/mol

  • 9. 
    When a mixture containing an equal concentration of glucose 6-phosphate and fructose 6-phosphate is incubated with the enzyme phosphohexose isomerase, the final mixture contains twice as much glucose 6-phosphate as fructose 6-phosphate.  Which one of the following statements is correct, when applied to the reaction below (R = 8.315 J/mol•K and T = 298 K)? Glucose 6-phosphate ↔ fructose 6-phosphate
    • A. 

      ΔG'° is +1.7 kJ/mol

    • B. 

      ΔG'° is –1.7 kJ/mol

    • C. 

      ΔG'° is incalculably large and negative

    • D. 

      ΔG'° is incalculably large and positive

    • E. 

      ΔG'° is zero

  • 10. 
    What is the standard-state free energy (ΔG°) for the hydrolysis of ATP to ADP? 
    • A. 

      +45.6 kJ/mol

    • B. 

      -45.6 kJ/mol

    • C. 

      -30.5 kJ/mol

    • D. 

      15.6 kJ/mol

    • E. 

      12.2 kJ/mol

  • 11. 
    Describe why anabolism and catabolism need to be precisely regulated. Include in your answer what is meant by reciprocal regulation of anabolic and catabolic pathways.
  • 12. 
    Describe using an equation, how a reaction in a biochemical pathway may occur spontaneously despite the standard free energy for that reaction being positive. Outline the difference between free energy and standard free energy in your answer.