Week 7 HW and Quiz
The standard reduction potentials for the following reactions are given below.Pyruvate + 2H+ + 2e- → lactate E° = -0.190 VNAD+ + 2H+ + 2e- → NADH/H+ E° = -0.320V.What is ΔG° for the overall spontaneous reaction, make use of the relationship between ΔE° and ΔG°?
-25 kJ/mol
The main energy-coupling compound in biochemical reactions that allows thermodynamically unfavorable processes to become favorable is ________.
ATP
Which statements about adenosine triphosphate (ATP) are true? ATP can be hydrolyzed to adenosine monophosphate and pyrophosphate. ATP is a carrier of cellular energy. ATP can be hydrolyzed to adenosine diphosphate and inorganic phosphate. ATP has two phosphoanhydride bonds.
All statements are true.
Which of the following molecule(s) has a higher phospho-transfer potential than that of ATP hydrolysis to ADP?
Creatine phosphate Submit
The standard reduction potential is a measure of the ability of an oxidant to ________ an electron.
Gain
What is the fate of the phosphate group that is removed when ATP is converted to ADP?
It is acquired by a reactant in an endergonic reaction.
A reaction with a ________ free energy of hydrolysis can be coupled to the hydrolysis of ATP to ADP and Pi.
Large positive
Consider the following reaction: NADH + FAD + H+ → NAD+ + FADH2. Which of the following statements is/are correct? Please refer to Table 3.6 or the standard reduction table in the lecture notes.
NADH is spontaneously oxidized. FAD is spontaneously reduced. The ΔE° for this reaction is positive.
The following two half reactions are paired together to create an overall spontaneous reaction. Which molecule is the reducing agent? NADP+ + 2H+ + 2e- -----> NADPH + H+ Eº´ = -0.320 V fumarate + 2H+ + 2e- -----> succinate Eº´ = 0.031 V What is the ΔEº´?
NADPH 0.351 V
Which of the following molecule(s) has a high enough phospho-transfer potential that it can phosphorylate AMP to ATP?
Phosphoenol pyruvate
Consider the following paired redox reaction: NADH + FAD + H+ → NAD+ + FADH2. Which of the following statements is correct? Please refer to Table 3.6 or the standard reduction table in the lecture notes.
This reaction is favorable.
In a redox reaction, BLANK are transferred from one chemical molecule to another.
electrons
In cells, most catabolic processes ATP and oxidized electron carriers.
generate; require
A molecule that is oxidized electrons.
loses
The conversion of ADP + Pi to ATP is endergonic by more than 30 kJ/mol. Which of the following hydrolyses could drive this conversion? Please consult Table 3.5.
phosphoenolpyruvate to pyruvate If an exergonic process is to be coupled to an unfavorable process such as the conversion of ADP + Pi to ATP, the second reaction coupled to the first must yield more energy than is required for the first to occur. This is the only reaction that fulfills this criterion to make an overall negative ΔG.
For a redox reaction to be spontaneous the overall ΔEº' is
positive and transfer of electrons occurs from a molecule with lower affinity to one with higher affinity.
The likelihood that a chemical molecule will be reduced is called the
standard reduction potential. Submit
The endergonic conversion of ADP to ATP requires more than 30 kJ/mol. The hydrolysis of phosphoenolpyruvate to pyruvate drives the conversion of ADP to ATP. What must be true about this hydrolysis?
the hydrolysis reaction is more exergonic than the conversion of ADP is endergonic
The phosphoryl group transfer potential is
the likelihood a molecule will transfer a phosphate group to another compound.
What is energy coupling?
the use of energy released from an exergonic reaction to drive an endergonic reaction
Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions?
γ-phosphate (the terminal phosphate) The γγ-phosphate is the primary phosphate group on the ATP molecule that is hydrolyzed when energy is needed to drive anabolic reactions. Located the farthest from the ribose sugar, it has a higher energy than either the αα- or ββ-phosphate.
