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Biochemistry 523
last quarter of course
124
Biochemistry
Undergraduate 4
12/09/2012

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Term
true
Definition
The NADH produced in glycolysis must be oxidized to NAD+ because the NAD+ is
essential for glycolysis to proceed.
Term
true
Definition
In yeast, aceltaldehyde is reduced to ethanol via the enzyme alcohol
dehydrogenase
Term
true
Definition
The inhibition of glyceraldehydes 3-phosphate dehydrogenase causes
accumulation of those intermediates from glucose 6-phosphate to glyceraldehydes 3-
phosphate.
Term
true
Definition
The citric acid cycle is part of the process respiration, but oxygen is not directly
involved in the reactions of the cycle.
Term
false
Definition
NADH is a small molecule that can freely diffuse through the inner mitochondrial
membrane.
Term
false
Definition
Ubiquinol is a water-soluble electron carrier in the electron transport chain.
Term
false
Definition
Isolated F1 subunits of the ATP synthase catalyze the net production of ATP in the
presence of ADP and Pi.
Term
true
Definition
ATPsynthases isolated from different sources often have different numbers of c
subunits.
Term
true
Definition
Under aerobic conditions, pyruvate is completely oxidized to CO2 and H2O.
Term
false
Definition
In yeast, under anaerobic conditions, piruvate is converted to lactate and NAD+ is
generated.
Term
true
Definition
Depending on the cell need for metabolic energy, pyruvate can be used to
produce fatty acids or certain amino acids.
Term
false
Definition
The citric acid cycle take place in specialized organelles called lysosomes.
Term
true
Definition
In the electron-transport chain, complex I transport out of the matrix 4 protons per
each pair of electrons.
Term
true
Definition
One cycle of the citric acid cycle produces 3 molecules of NADH and one
molecule of QH2 (ubiquinol).
Term
true
Definition
NADH inhibits (negatively regulates) the citric acid cycle.
Term
true
Definition
Cytric acid intermediates are precursors of other molecules.
Term
higher rate of lactate formation
Definition
In comparison with the resting state, actively contracting muscle tissue shows a:
Term
C-2 (methyl group) of ethanol
Definition
If glucose labeled with 14C in C-1 were fed to yeast carrying out the ethanol
fermentation, where would the 14C label be in the products?
Term
NAD+
Definition
The ultimate electron acceptor in the fermentation of glucose to ethanol is:
Term
ATP
Definition
Which of the following is NOT required for the oxidative decarboxylation of pyruvate
to form acetyl-CoA?
Term
Succinate dehydrogenase
Definition
All of the oxidative steps of the citric acid cycle are linked to the reduction of NAD+
EXCEPT:
Term
two carboxyl groups derived from oxaloacetate
Definition
The two molecules of CO2 produced in the first turn of the citric acid cycle have their
origin in the:
Term
H2O
Definition
Almost all of the oxygen (O2) one consumes in breathing is converted to:
Term
FADH2 + Q  FAD + QH2
Eo’ = 0.045 V – (-0.219 V) = 0.264 V
Go’ < 0, therefore it is spontaneous.
Definition
The standard reduction potential for ubiquinone (Q) is 0.045V, and the standard
reduction potential (Eo’) for FAD is -0.219V. Is the oxidation of FADH2 by ubiquinone
spontaneous? Justify. Eo’ = Eo’ (oxidant) – Eo’ (reductant), and Go’ = -n F Eo’
Term
QH2 + 2 Cyt c (Fe3+)  Q + 2 Cytc (Fe2+) + 2 H+
Definition
Write the net redox reaction for complex III of the electron transport chain (structure
of the compounds are not required, but equation has to be clearly balanced in mass and
charge).
Term
10__. Justify

3 NADH 7.5
1 QH2 1.5
1 GTP 1
Definition
How many molecules of ATP are produced per molecule of Acetyl-CoA:
Term
34__ Justify.
2 NADH 5
4 ATP 4
2 pyruvate 2 NADH 5
6 NADH 15
2 QH2 3
2 GTP 2
Definition
How many molecules of ATP are produced per molecule of Fructose-1,6-bisphosphate:
Term
12 NADH
Definition
How many molecules of NADH are oxidized by the electron transport chain when 6
molecules of oxygen (O2) are reduced?
Term
a-c
The crosslinking inhibit the rotation of the c/sigma/gamma subunits.
Definition
Indicate two inter-subunit Cys crosslinking of the ATPsynthase that will result in the
inhibition of ATP synthesis. Justify.
Term
ethanol and CO2
Definition
Glucose is converted to ____ in yeast under anaerobic conditions.
Term
8
Definition
What is the net energetic cost of converting two phosphoenol pyruvate to one glucose by gluconeogenesis in ATP equivalents? assuming 3ATP are obtained per NADH
Term
FMN, iron-sulfur clusters
Definition
Several prosthetic groups act as redox centers in complex I, including
Term
succinyl-CoA synthetase
Definition
which of the following enzymes of the citric acid cycle produce a molecule of GTP?
Term
lipoic acid (lipoamide)
Definition
Which of the following coenzymes is required by E2 of the pyruvate dehydrogenase complex?
Term
lactate
Definition
Glucose is converted to ______ in skeletal muscle under anaerobic conditions.
Term
6
Definition
What is the net energetic cost of converting two pyruvate to one glucose by gluconeogenesis in ATP equivalents?
Term
thiamine pyrophosphate
Definition
Which of the following coenzymes is required by E1 of the pyruvate dehydrogenase
complex or catalytic activity?
Term
succinate dehydrogenase
Definition
Which of the following enzymes of the citric acid cycle contains an FAD prosthetic
group?
Term
cytochrome c1, cytochrome b, iron-sulfur protein (Rieske).
Definition
The functional core of Complex III includes:
Term
Glycogen synthesis would slow down, Maintaining proper blood sugar levels would be more difficult.
Definition
Which of the following could result from having few or no α-1,6 linkages in glycogen?
Term
alcohol dehydrogenase, lactate dehydrogenase
Definition
Which of the following sets of enzymes catalyze reversible reactions of fermentation and also transfer a hydride ion from NADH?
Term
carbohydrate loading
Definition
Excess glucose is stored as muscle or liver glycogen, which can be broken down to supply energy during the event.
Term
to prevent the formation of glucose, to maintain energy supplies in muscle cells, to prevent energy waste by conserving the ATP that would be needed to phosphorylate glucose
Definition
Water is prevented from entering the active site of glycogen phosphorylase. What is the advantage of excluding water from the active site?
Term
glucose 6-phosphatase
Definition
A baby is brought to the doctor by his parents after experiencing irritability and seizures when he sleeps through the night. Tests showed fasting hypoglycemia (low blood glucose concentration), increased serum lipid levels, elevated blood lactate after glucose administration, and elevated uric acid. The child also had an enlarged abdomen. Glycogen levels were increased in hepatocytes. (Assume the glycogen is of normal structure.) The patient has a glycogen storage disease. Which enzyme of glycogen metabolism is affected?
Term
pyruvate + NAD+ + CoA -> acetyl CoA + NADH + CO2
Definition
Complete the overall reaction catalyzed by the pyruvate dehydrogenase complex.
Term
1,3,4
Definition
Identify the steps in the cycle catalyzed by the enzymes listed in the table that are exergonic
Term
8
Definition
Identify the steps in the cycle catalyzed by the enzymes listed in the table that are endergonic
Term
6
Definition
Identify the steps in the cycle catalyzed by the enzymes listed in the table that are at equilibrium
Term
citrate synthase
Definition
Citric acid cycle: step 1 AcetylCoA -> citrate
Term
aconitase
Definition
Citric acid cycle: step 2 citrate = isocitrate
Term
isocitrate dehydrogenase
Definition
Citric acid cycle: step 3 isocitrate -> alpha ketoglutarate
Term
alpha ketoglutarate dehydrogenase
Definition
Citric acid cycle: step 4 alpha ketoglutarate -> succinyl-CoA
Term
succinyl-CoA synthetase
Definition
Citric acid cycle: step 5 succinyl-CoA = succinate
Term
succinate dehydrogenase
Definition
Citric acid cycle: step 6 succinate = fumerate
Term
fumerase
Definition
Citric acid cycle: step 7 fumerate = malate
Term
malate dehydrogenase
Definition
Citric acid cycle: step 8 malate = oxaloacetate
Term
NADH, succinyl-CoA, citrate
Definition
Which of the following molecules inhibit reaction 1?
Term
NADH
Definition
Which of the following molecules inhibits reaction 3?
Term
Ca2+, ADP
Definition
Which of the following molecules or ions activate reaction 3?
Term
NADH, Succinyl CoA
Definition
Which of the following molecules inhibit reaction 4?
Term
carboxylation of pyruvate to form oxaloacetate, transamination of glutamate, yielding α-ketoglutarate, oxidation of odd-chain fatty acids to yield succinyl-CoA, synthesis of fumarate from aspartate
Definition
Identify the reactions that may be anaplerotic reactions of the citric acid cycle.
Term
Aconitase catalyzes the dehydration and hydration of citrate, Aconitase has the active iron-sulfur center Fe4S4
Definition
Which of the following statements regarding aconitase are correct?
Term
QH2, GTP, NADH
Definition
Which of the following compounds in the citric acid cycle have high-energy bonds or transfer chemical energy?
Term
–a reductive pathway and an oxidative pathway.
Definition
The citric acid cycle may have originated from two pathways
Term
true
Definition
The citric acid cycle may have evolved from two biosynthetic pathways in early life forms.
Term
true
Definition
Early organisms may have lacked the enzyme α-ketoglutarate dehydrogenase.
Term
true
Definition
Although some organisms do not use the citric acid cycle under anaerobic conditions, they use a reductive pathway similar to the citric acid cycle to generate some larger molecules.
Term
malate synthase, isocitrate lyase
Definition
Which two enzymes, found in plants and not in animals, make this conversion of fat to carbohydrate possible?
Term
Concentrations in the cell might not be 1 M.
Definition
Why might the standard reduction potential for a reaction differ from the reduction potential found in a cell?
Term
specifies a hydrogen ion concentration of 10–7 M
Definition
When considering free energy change, biochemists define a biochemical standard state, ΔG°\', which differs from the chemical standard state, ΔG°. A similar distinction must be made with reduction potentials. (a) In contrast to the chemical reduction potential, ΔE°, the biochemical standard reduction potential, ΔE°\'...
Term
true
Definition
Electron transfer in the ETC is coupled to proton transfer from the matrix to the intermembrane space.
Term
true
Definition
Prosthetic groups, such as iron-sulfur centers, are directly involved with electron transfer.
Term
true
Definition
Electrons generated by the citric acid cycle in the mitochondrial matrix enter the ETC.
Term
true
Definition
Electron carriers are organized into four complexes of proteins and prosthetic groups.
Term
true
Definition
The reactions of the ETC take place in the inner membrane of mitochondria.
Term
electron transfer from NADH to ubiquinone, NADH ubiquinone oxidoreductase
Definition
Complex I
Term
coenzyme Q
Definition
ubiquinone
Term
electron transfer from succinate to ubiquinone, succinate-coenzyme Q oxidoreductase
Definition
Complex II
Term
electron transfer from ubiquinol to cytochrome c, coenzyme Q-cytochrome c oxidoreductase
Definition
Complex III
Term
electron transfer from cytochrome c to O2, cytochrome c oxidase
Definition
Complex IV
Term
enzyme: pyruvate dehydrogenase, cofactor: TPP (thiamine pyrophosphate)
Definition
E1
Term
enzyme: dihydrolipoyl transacetylase, cofactor: lipoate coenzyme A
Definition
E2
Term
enzyme: dihydrolipoyl dehydrogenase, cofactor: FAD, NAD+
Definition
E3
Term
citric acid cycle
Definition
The complete oxidation of one glucose molecule yields 30 or more ATP. Glucose catabolism includes glycolysis, pyruvate oxidation, and the citric acid cycle. The total yield of ATP includes ATP, GTP, and reduced cofactors that yield ATP from the electron transport chain and oxidative phosphorylation. Which of the following processes yields the most ATP? When determining the ATP yield for each process, include ATP derived from reduced cofactors.
Term
NADH, FADH2
Definition
Which compounds donate electrons to the electron transport chain?
Term
O2
Definition
Which of the following is the final electron acceptor?
Term
H2O, NAD+, ATP, FAD
Definition
Which of the following are the final products of the electron transport chain and oxidative phosphorylation?
Term
NADH – coenzyme Q – cytochrome b – cytochrome a – O2
Definition
Which of the following options shows the correct order that each electron carrier first appears in the electron transport system?
Term
true
Definition
Hydrogen ion concentration is higher in the intermembrane space than in the mitochondrial matrix.
Term
true
Definition
Hydrogen ions are actively transported out of the mitochondrial matrix.
Term
true
Definition
Oxidative phosphorylation relies on the hydrogen ion concentration gradient generated and maintained by the electron transport chain.
Term
into the mitochondrial matrix
Definition
Which direction is ADP3– transported during times of active oxidative phosphorylation?
Term
the electrochemical gradient (membrane potential)
Definition
What drives the transport of adenine nucleotides?
Term
1 ADP : 1 ATP
Definition
What is the ratio of ADP to ATP transported by the adenine nucleotide translocase? That is, how many ADP are transported for each ATP transported?
Term
H and H2PO4– are transported into the matrix in a process driven by the proton gradient.
Definition
What drives the transport of H2PO4– across the membrane? Which direction is it transported during oxidative phosphorylation?
Term
4
Definition
How many H ions are required to be moved across the membrane for the synthesis of 1 ATP? Include both the H ions needed for ATP synthesis itself and for other transport required for ATP synthesis.
Term
There would be an uncoupling of proton translocation and ATP synthesis, ATP synthase would remain sensitive to F0 proton conduction inhibitors.
Definition
A mutation in human ATPase 6 (which corresponds to E. coli subunit a) from leucine to arginine at position 156 may allow the movement of protons across the membrane, but not the rotation of the ring of c subunits. How might this possible mechanism affect the function of ATP synthase?
Term
F1 F0 -type ATPase
Definition
the enzyme primarily responsible for the production of ATP is _______
Term
one of the major chemical reactions in living organisms
Definition
ATP production is ____
Term
12.5
Definition
How many molecules of ATP are produced per molecule of pyruvate?
Term
2.5
Definition
How many molecules of ATP are produced per molecule of NADH?
Term
32
Definition
How many molecules of ATP are produced per molecule of glucose?
Term
13.5
Definition
How many molecules of ATP are produced per molecule of phosphoenolpyruvate?
Term
3
Definition
How many O2 molecules are reduced when 6 molecules of NADH are oxidized
by the electron transport chain?
Term
a-c
Definition
What inter-subunit Cys crosslinking inhibit ATP synthesis?
Term
delta G = -nF delta E
Definition
How is the redox potential (ΔE0’) related to the free-energy change of a reaction
(ΔG0’)?
Term
ubiquinol is hydrophobic
Definition
Explain why ubiquinol is an effective mobile electron carrier in the electrontransport
chain?
Term
highest
Definition
Oxygen is the most effective oxidizing agent than any other biological molecule.
Compared to other biological molecules, how is the standard redox potential for
oxygen going to be: the lowest or the highest?
Term
4,0,4
Definition
How many protons are transported out of the matrix for each complex (I, II, and
III) per each pair of electrons?
Term
environment and amino acids
Definition
What determines the redox potential and absorption properties of the different
cytochromes?
Term
NADH + H+ + Q = NAD+ + QH2
Definition
Write the net redox reactions for complex I
Term
QH2 + 2Cyt3+ = Q + 2Cyt2+ 2H+
Definition
Write the net redox reactions for complex II
Term
4Cyt2+ + O2 + 4H+ = 4Cyt3+ + 2H2O
Definition
Write the net redox reactions for complex III
Term
succinyl CoA synthase
Definition
produces GTP in mammals
Term
embedded in inner membrane
Definition
succinate dehydrogenase
Term
fumerase
Definition
reversible hydration of double bond
Term
malate dehydrogenase
Definition
produce NADH
Term
1.pyruvate carboxylase
2.phosphoenylpyruvate carboxykinase
3.fructose biphosphetase
4.glucose 6-phosphetase
Definition
name, in order, the enzymes involved in gluconeogenesis of pyruvate to glucose
Term
matrix
Definition
citric acid cycle, or krebs cycle, occurs in the _______
Term
pyruvate + NAD+ + CoA -(pyruvate dehydrogenase)-> acetyl CoA + NADH + CO2
Definition
How does pyruvate get into the citric acid cycle?
Term
F1F0-type ATPase
Definition
ATP synthase
Term
coupling
Definition
linkage of
endergonic and exergonic reactions in F1F0 is called
Term
true
Definition
When the interaction between F1 and F0 is
disrupted so that energy transduction is lost, the
system is said to be uncoupled
Term
happier than a lion
Definition
how will you feel if you get an A+ on this exam
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