The standard free energy change for the hydrolysis of ATP to ADP and inorganic phosphate (Pi) is about -30 kJ/mol but in the red blood cell the actual free energy change for this reaction is about -52 kJ/mol. This means that:
The concentration of inorgani
The concentration of ATP is greater than the product of the concentrations of ADP and Pi.
In the equation, which is the oxidizing agent?
NAD+
Ethanol
Acetaldehyde
NADH
H+
NAD+
Which of the following is FALSE for catabolic pathways?
They extract usable chemical energy from fuel molecules.
They generate ATP.
They are oxidative.
They generate oxidized enzyme cofactors
They generate oxidized enzyme cofactors
Which of the following is always involved in biological oxidation-reduction reactions?
Formation of water.
Inner mitochondrial membrane.
Transfer of electron(s).
Oxygen.
Transfer of electron(s).
Which of the following features are common to all anabolic pathways?
They break down complex molecules.
They require energy
They are oxidative.
Their overall free energy change is positive
They require energy
Which of the following statements concerning metabolic pathways is TRUE?
All reactions in a metabolic pathway are tightly regulated.
Opposing metabolic pathways do NOT occur.
Many of the reactions in a metabolic pathway are thermodynamically reversible.
M
Many of the reactions in a metabolic pathway are thermodynamically reversible.
What is the role of phosphocreatine in muscle?
To make glucose in gluconeogenesis.
To make more ATP.
To act as an electron carrier.
To use in place of ATP
To make more ATP.
Which of the following phosphorylated compounds would be considered a "low-energy" intermediate in metabolism, relative to the others?
ATP
Phosphocreatine
Glucose-6-phosphate
1,3-Bisphosphoglycerate
Phosphoenolpyruvate
Glucose-6-phosphate
Which of the following statements is FALSE with respect to FADH2 and NADH?
Both FADH2 and NADH are dinucleotides.
Both FADH2 and NADH can reversibly carry two electrons.
FADH2 possesses only one sugar while NADH has two.
FADH2 has a flavin base, while NAD
FADH2 possesses only one sugar while NADH has two.
Which of the following is FALSE for anabolic pathways?
They re-oxidize reduced enzyme cofactors.
They extract usable chemical energy from fuel molecules.
They use ATP.
They are reductive
They extract usable chemical energy from fuel molecules.
Which of the following terms accurately describes enzyme-catalyzed pathways that yield energy and breakdown complex molecules to simpler precursors?
Catabolic pathways
Amphibolic pathways
Metabolic pathways
Anabolic pathways
Catabolic pathways
Which of the following is NOT a high energy intermediate of metabolism?
Thioesters
NADPH
AMP
ATP
All of the above are high energy intermediates
AMP
Examine the following reactions:
Reaction 1. Glycerol 1-phosphate + H2O ----> Glycerol + Pi G = -9
Reaction 2. ATP + H2O --------> ADP + Pi + H+ G = -30
What is the balanced equation and the G of the coupled reaction?
Glycerol 1-phosphate + ADP + H+ -----
Glycerol + ATP -----> Glycerol 1-phosphate + ADP + H+ G = -21
Which of the following correctly describes a catabolic pathway?
Catabolic pathways may require an input of energy.
Catabolic pathways may reduce NAD+.
Catabolic pathways synthesize larger molecules from smaller precursors.
Both A and B are correct.
Both B
Both A and B are correct.
A hypothetical metabolic pathway is depicted below. A, B, C, D and E are the metabolic intermediates. E1 through E4 catalyze the 4 reactions. The free energy change for each reaction is shown below the arrow in kJ/mol. What MOST LIKELY happens if the conc
The flux through the pathway from C to E will increase.
Which of the following terms accurately describes an enzyme-catalyzed pathway that can both reduce electron carriers and extract usable chemical energy from fuel molecules?
Metabolic
Catabolic
Anabolic
Amphibolic
None of the above
Catabolic
Why is acetyl-CoA considered a high energy molecule?
It contains an ester bond.
Large amounts of ATP are released upon oxidation.
It contains a thioester bond.
Large amounts of ATP are released upon deacetylation
It contains a thioester bond.
Prokaryotes that are able to synthesize all of their cellular components from simple molecules such as CO2, H2O, NH3, and H2S are called ______
obligate aerobes
anabolic
catabolic
acyl phosphate
adenylate kinase
proteomics
NAD+
NADPH
pyrophosphatase
autot
autotrophs
Organisms that require oxygen are called ______.
acyl phosphate
autotrophs
obligate aerobes
oxidation
?G�'
NADPH
proteomics
anabolic
pyrophosphatase
adenylate kinase
NAD+
catabolic
obligate aerobes
Biomolecules are synthesized from simpler components in ______ pathways.
acyl phosphate
pyrophosphatase
proteomics
oxidation
?G�'
NAD+
anabolic
NADPH
adenylate kinase
autotrophs
obligate aerobes
catabolic
anabolic
A loss of electrons from a substance is known as ______.
obligate aerobes
anabolic
oxidation
autotrophs
proteomics
acyl phosphate
NADPH
pyrophosphatase
?G�'
adenylate kinase
catabolic
NAD+
oxidation
The oxidized form of NADH is ______.
obligate aerobes
anabolic
pyrophosphatase
catabolic
?G�'
adenylate kinase
acyl phosphate
proteomics
NAD+
oxidation
NADPH
autotrophs
NAD+
The standard reduction potential at the biochemical standard state is symbolized as ______.
NAD+
anabolic
E
pyrophosphatase
acyl phosphate
obligate aerobes
oxidation
autotrophs
?G�'
adenylate kinase
catabolic
NADPH
proteomics
E
Organisms that are poisoned by oxygen are :
facultative anaerobes
obligate anaerobes
autotrophs
chemolithotrophs
obligate aerobes
obligate anaerobes
Consider the following metabolic reaction:
Succinyl-CoA + Acetoacetate Acetoacetyl-CoA + Succinate ?G�' = -1.25 kJ/mol
What is the Keq for this reaction at 25�C?
03.21
0.602
1.00
4.22 x 102
1.66
1.66
Consider the following metabolic reaction:
Succinyl-CoA + Acetoacetate Acetoacetyl-CoA + Succinate ?G�' = -1.25 kJ/mol
The ?G�' for the hydrolysis of Succinyl-CoA is -33.9 kJ/mol. What is the ?G�' for the hydrolysis of Acetoacetyl-CoA: Acetoacetyl-CoA Ace
-32.7 kJ/mol
Consider the following metabolic reaction:
Succinyl-CoA + Acetoacetate Acetoacetyl-CoA + Succinate ?G�' = -1.25 kJ/mol
This reaction is:
favorable under standard conditions.
not favorable under standard conditions.
always exergonic and can never proceed i
favorable under standard conditions.
The Keq is 0.503 at 25�C for the following reaction. What is the ?G�' for this reaction? D-Glucose-6-phosphate D-Fructose-6-phosphate
-1,700 J/mol
-2,870 J/mol
+143 J/mol
+1.70 kJ/mol
none of the above
+1.70 kJ/mol
Consider the following metabolic reaction:
2-Phosphoglycerate 3-Phosphoglycerate ?G�' = -4.40 kJ/mol
What can be said about this reaction when the concentration of 2-phosphoglycerate is 0.490 mM and the concentration of 3-phosphoglycerate is 2.90 mM at 25
This reaction is at equilibrium under these conditions.
Consider the following metabolic reaction:
3-Phosphoglycerate 2-Phosphoglycerate ?G�' = +4.40 kJ/mol
What is the ?G for this reaction when the concentration of 2-phosphoglycerate is 0.290 mM and the concentration of 3-phosphoglycerate is 2.90 mM at 37�C?
-1.54 kJ/mol
Which of the numbered arrows in the figure points toward a high-energy phosphoanhydride bond?
1
2
3
4
5
5
Given that the standard reduction potential of oxaloacetate is -0.166 V and the standard reduction potential of NAD+ is -0.315 V. What is the ? for the oxidation of malate by NAD+: Malate + NAD+ Oxaloacetate + NADH + H+
+0.0523 V
-4.81 V
+0.149 V
+ 4.81 V
-0.149 V
The process by which nutrients are degraded in order to salvage their components and/or to generate energy is most specifically called:
anaerobism
anabolism
catabolism
glycolysis
metabolism
catabolism
ATP contains one ________ bond and two ______ bonds
phosphoester; glycosidic
glycosidic; amide
amide; phosphoanhydride
phosphoester; phosphoanhydride
phosphoanhydride; phosphoester
phosphoester; phosphoanhydride
The ______ is equal to the rate of synthesis minus the rate of breakdown of the metabolite.
metabolic rate
Keq
endergonicity
flux
none of the above
flux
Cells control or regulate the flux through metabolic pathways by:
allosteric control of enzymes.
covalent modification of enzymes.
genetic control of the concentrations of enzymes.
all of the above
none of the above
all of the above
Food intake and use is commonly called:
anabolism
digestion
nutrition
metabolism
catabolism
nutrition
Obligate aerobes:
are poisoned by O2.
employ oxidizing agents such as sulfate or nitrate.
resemble the earliest life forms.
all of the above
none of the above
none of the above
In eukaryotes, glycolysis typically occurs in the
nucleus
mitochondrion
cytosol
lysosome
golgi apparatus
cytosol
Acyl phosphates such as 1,3-bisphosphoglycerate have a ______ phosphoryl group transfer potential compared to ATP, which can be recognized by the _______ ?G�' values for hydrolysis.
greater; more positive
greater; more negative
lower; more positive
lower;
greater; more negative
Consider the following metabolic reaction important in muscle and nerve cells:
ATP + creatine phosphocreatine + ADP ?G�' = +12.6 kJ/mol
Under intracellular conditions, the ?G for the reaction, which is catalyzed by the enzyme creatine kinase, is ~0 kJ/mol
the reaction operates close to equilibrium in cells.
In redox half-reactions, a more positive standard reduction potential means
the oxidized form has a higher affinity for electrons
the oxidized form has a lower affinity for electrons
the primary ionic form has a higher positive charge
the reduced form is
the oxidized form has a higher affinity for electrons
The ubiquitous chemistry of acetyl-CoA is centered on its high-energy _________________ bond.
phosphothioester
phosphoester
ester
thioester
phosphoanhydride
thioester
Which of the following best describes a typical metabolic pathway?
A series of enzyme-catalyzed steps, most of which are operating near equilibrium, but one or more is highly favorable and irreversible
A series of enzyme-catalyzed steps, all of which are
A series of enzyme-catalyzed steps, most of which are operating near equilibrium, but one or more is highly favorable and irreversible
Which of the following is a long term control mechanism?
Genetic control
Allosteric control
Covalent modification
Substrate cycles
Genetic control
Where does ATP hydrolysis rank among the standard free energies of phosphoryl group transfer of all biological molecules?
ATP hydrolysis has an intermediate free energy change.
ATP hydrolysis has nearly the smallest negative free energy change.
ATP hydrol
ATP hydrolysis has an intermediate free energy change.
Why is the term "high-energy" bond somewhat of a misnomer in reference to ATP and similar compounds?
These bonds are actually intermediate in energy.
These compounds are highly charged.
These bonds require a large amount of energy to break, but do not con
The term "high-energy" refers to the difference in free energy between the compound and it hydrolyzed product. It does not refer to the bonds energy.
Which of the following is least important for understanding a metabolic pathway?
To know the E.C. numbers for all the enzymes of the pathway.
To know the sequence of reactions and their energetics.
To know the mechanisms of the enzymes at each step.
To kn
To know the E.C. numbers for all the enzymes of the pathway.
What is one of the advantages of the presence of different catabolic and anabolic pathways?
It prevents coordinated regulation.
It allows for independent regulation of the two pathways.
It is not important, but arose by evolutionary accident.
Few enzymes
It allows for independent regulation of the two pathways.
What characterizes the rate-determining step of a metabolic pathway?
It functions far from equilibrium and it has a large negative free energy change.
It functions near equilibrium and it has a large positive free energy change.
It functions near equilibr
It functions far from equilibrium and it has a large negative free energy change.
Which of the following best describes the flux of metabolites through a highly exergonic step?
The rates of the forward and the reverse steps are both very high.
The rate of the forward step is much greater than that of the reverse step.
The rate of the r
The rate of the forward step is much greater than that of the reverse step.
How do electrostatic interactions contribute to the free energy of hydrolysis of ATP?
Electrostatic repulsion stabilizes ATP, and therefore makes hydrolysis less favorable.
They have little effect since ATP, ADP and Pi are all negatively charged.
Electros
Electrostatic repulsion destabilizes ATP relative to the hydrolysis products, and therefore makes hydrolysis favorable.
If the ?G0' for hydrolysis of glucose-1-phosphate is -13.8 kJ/mol, and for hydrolysis of ATP is -30.5 kJ/mol, what will be the ?G�' for the phosphorylation of glucose by ATP to produce glucose-1-phosphate?
-16.7 kJ/mol
+16.7 kJ/mol
+44.3 kJ/mol
-44.3 kJ/m
-16.7 kJ/mol
What characterizes a spontaneous redox reaction?
?E (emf) is negative and ?G is negative.
?E (emf) is positive and ?G is positive.
?E (emf) is negative and ?G is positive.
?E is positive and ?G is negative.
?E is positive and ?G is negative.