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25 Cards in this Set
- Front
- Back
True or False ATP is known as the ‘energy currency’ of the cell and needs to be relatively reactive for this role. However, it can remain in a bottle on the shelf (usually in a refrigerator) for many months unchanged. This is because ATP has a relatively high free energy of hydrolysis. |
False |
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FAD transfers electrons by.. |
accepting one electron and one hydrogen atom in its structure |
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The free energy of ATP hydrolysis essentially comes from.. |
forming ADP and phosphate |
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The Free Energy contained in one mol of glucose (C6H12O6), assuming -220kJ/mol for each reduced bond, is: |
5 C-C bonds = 5 x -220 kJ/mol = -1100 kJ/mol7 C-H bonds = 7 x -220 kJ/mol = -1540 kJ/mol Total estimated energy generated from one mole of glucose = -2640kJ/mol |
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The Gibbs free energy change for ATP hydrolysis is large and negative in part because:* A. the products are relatively less stable B. the products (phosphate and ADP) are less soluble in water than ATP C. there is less electrostatic repulsion among four negative charges of phosphate after hydrolysis D. the terminal anhydride bonds in ATP are ‘weaker’ compared with the bonds in the products. |
C and D |
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Exergonic reactions can be used to ‘drive’ endergonic reactions. This process requires:* A. a mechanism for the transfer of energy from the endothermic reaction to the exothermic reactions B. a mechanism for the transfer of energy from the exergonic reaction to the endergonic reaction C. a common intermediate shared by the reactions that are coupled D. a transport protein that couples the two reactons |
B and C |
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Calculate (with 2 significant figures) the standard Gibbs Free Energy available for the reaction: Pyruvate + NADH + H+ ——> lactate + NAD+ Given the following information: Pyruvate + 2H+ + 2e- ——> lactate E’o = -0.19V NAD+ + H+ + 2e- ——> NADH E’o = -0.32V Faradays constant (F) = 96485 J V-1 mol-1 |
ΔG’o = -nFΔE’o -25 kJ/mol |
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Reduction potentials can be used to:* A. estimate the Free Energy of an oxidation-reduction reaction B. estimate the enthalpy of ATP hydrolysis C. track the number of electrons stored or transferred D. estimate the amount of volts in hydrogen atoms |
A and C |
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Ubiquinone transfers electrons by... |
accepting two electrons and two hydrogen ions in its structure |
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Fructose 6-phosphate + ATP -> fructose 1,6-bisphosphate + ADP Calculate the overall free energy of this reaction given the information below R = 8.315 J/mol.K T = 25°C ATP —> ADP + Pi ΔG’o = -30.5kJ/mol Fructose 1,6-bisphosphate -> fructose 6-phosphate + Pi ΔG’o = -16.0kJ/mol |
-14.5 |
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True or False: If the standard Gibbs Free Energy for the hydrolysis of ATP is -30.5kJ/mol, then it would take +30 kJ/mol to synthesise ATP from the concentrations of ADP and Pi that exist in the cell |
False |
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A carbon is oxidised if... |
The number of hydrogen atoms bonded to a carbon decreases and The number of bonds to more electronegative atoms (e.g. O, N, F, Cl, I or S) increases |
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A carbon is reduced if... |
The number of bonds to more electronegative atoms (e.g. O, N, F, Cl, I or S) decreases and The number of hydrogen atoms bonded to a carbon increases |
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True or False The tendency of a metabolic reaction to proceed is due to the free energy of both the reactants and products as well as the change in randomness of that reaction |
True |
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Sucrose + Pi ---> glucose 1-phosphate + fructose Calculate the standard free energy for the reaction above given the following: sucrose + H2O ---> glucose + fructose ΔG'o =-29 glucose 1-phosphate + H2O ---> glucose + Pi ΔG'o = -21 kJ/mol |
-29 + 21 = -8kJ/mol |
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Which of the following half-reactions has the greatest reduction potential (i.e. can act as the better reducing agent) compared with all the others in the list. A. E’o =0.421V B. E’o = 0.031V C. E’o = 0.295VD. NA D. E’o = -0.320V |
D |
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Electrons are transferred from [A] reactions in the cell to specific [B]. The [C] then transfer the electrons to other [D] reactions and [E] in the inner mitochondrial membrane. The flow of electrons through these carriers and reactions in the inner mitochondrial membrane eventually contributes to the production of [F] molecule. |
A- oxidation-reduction B- election carriers C- election carriers D- oxidation-reduction E- election carriers F- ATP |
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overall charge of NAD+ |
negative |
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True or False ATP is known as the ‘energy currency’ of the cell because like money it is the intermediate in the transaction of ‘value’ between different ‘entities’. |
True |
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The free energy for ATP hydrolysis in vivo is actually greater than the standard free energy change of -30 kJ mol-1 because: A. it can participate in phosphoryl group transfers. B. it can easily be formed from other nucleotide triphosphates. C. of the actual concentrations of ATP and its hydrolysis products in cells. D. it has stronger electrostatic repulsion. E. All of the above |
C |
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In which direction to electrons flow? High to low E values Low to high E values |
Low to high |
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True or false In a coupled reaction we can add the ΔG'o values for each reaction to get the ‘overall’ ΔG'o values for the combined reaction. |
True |
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‘Reduced bonds’ are a concept that allows us to: A. estimate the reduction potential of a molecule B. estimate the enthalpy of a molecule C. estimate the free energy of a molecule D. estimate the entropy of a molecule |
B |
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The Gibbs Free energy change for ATP hydrolysis is large and negative in part because: A. the products (ADP and phosphate) are relatively more stable B. the products (ADP and phosphate) are more soluble in water than ATP C. there is increased electrostatic repulsion among four negative charges of phosphate after hydrolysis D. the terminal anhydride bonds in ATP are ‘stronger’ compared with the bonds in the products. |
A and B |
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NAD+ transfers electrons by: A. accepting two electrons and two hydrogen atoms in its structure B. accepting one electron at a time in its structure C. accepting a hydroxyl group in its structure D. accepting a hydride ion in its structure |
d |