10 Principles Of Bioenergetics

12 Questions | By Catherinehalcomb | Updated: Mar 21, 2022 | Attempts: 2471

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1.

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.
2.

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.
3.

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
4.

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
5.

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)
6.

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
7.

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
8.

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
9.

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
10.

Given the following information, calculate the actual free energy of the below reaction. A → B; K_eq = 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
11.

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
12.

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