Place the following reaction intermediates of the citric acid cycle in chronological order
malate
fumarate
succinylCoA
citrate
a-ketogluterate
citrate, alpha ketogluterate, succinyl CoA, fumarate, malate
Oxalosuccinate is a transient intermediate formed during which of the following reactions?
it is formed when isocitrate is oxidized to from NADH2 and CO2
FADH2 is a product of which of the following reactions?
succinate dehydrogenase
NADH is formed in which of the following reactions?
isocitrate dehyrogenase, alpha ketogluterate dehydrogenase, malate dehydrogenase
In the glyoxylate cycle, two carbons molecules are converted to precursors of which of the following?
glucose
Which of the following enzymes is unique to the glyoxylate cycle?
isocitrate lyase, and malate synthase
The regulated enzymes of the citric acid cycle include
citrate synthase, isocitrate dehydrogenase, alpha ketogluterate dehydrogenase
The enzymes involved in citrate metabolism incldue all of the following except?
citrate lyase, malate dehydrogenase, malic enzyme
Redox potential is best defined as...
the tendency for a specific substance to gain electrons
In order to determine the standard voltage of a reaction
solutes are at 1M concentration, all gases at 1 atm, temp is 25C
Which of the following reactions is an oxidation reaction?
Example: fumarate + 2h+ + 2e-
Which of the following reactions has an oxidized product?
...
In any redox reaction, an electron donor is ___?
oxidized
In a redox reaction, an electron acceptor is ___?
reduced
Each turn of the citric acid cycle produces how many moles of CO2?
2
Acetyl CoA that is consumed by the citric acid cycle is produced from which of the following biochemical pathways?
glycolytic pathway
Which of the following is the strongest reducing agent? (The standard reduction potential of each species is provided in parentheses)
the one with the most negative reduction potential
Which of the following reacts with Acetyl CoA to form citrate?
oxaloacetate
The redox reaction in which succinate is converted to fumarate uses FAD rather than NAD+ because?
the oxidation of an alkane requires a stronger oxidizing agent than NAD+
Most of the energy released during the electron transport chain is used to drive?
atp synthesis
Which of the following reactions require GDP?
the cleavage of succinyl-coA
How many oxidation steps are in the citric acid cycle?
4
The product of the first reaction of the citric acid cycle is?
citrate
Which of the following reaction requires a substrate level phosphorylation?
cleavage of succinyl CoA
The carbon skeleton of which of the following are direct precursors of amino acids?
oxaloacetate and alpha ketogluterate
Which of the following is not directly required for the activity of pyruvate dehydrogenase?
pyruvate dehydrogenase, dihydrolipoyl transcetylase, dihydrolipoyl dehydrogenase are required
Which of the following is a positive effector of isocitrate dehydrogenase?
high concentrations of ADP and NAD+
Consider the following reaction:
Pyruvate + NADH + H+ --� Lactate + NAD+
The half cell reaction ( with their standard reduction potentials ) are
Pyruvate + 2H+ + 2e- � Lactate (-0.19V)
NAD+ + H+ +2e- � NADH (-0.32V) --->
What is the reduction potential fo
0.32-0.19=.13V
The overall reaction catalyzed by pyruvate dehydrogenase is which of the following?
oxidative decarboxylation
The main toxic effect of oxygen is due to which of the following?
ROS react with and damage biomolecules
The primordial reductive branch of the citric acid cycle was the primary means of producing which of the following?
succinate, succinyl-CoA
The primordial oxidation branch of the citric acid cycle used which of the following as the final electron acceptor?
sulfur
The enzyme which links the two branches of the citric acid cycle is which of the following?
alpha ketogluterate dehydrogenase, succinyl CoA dehydrogenase
The glyoxylate cycle is a mechanism whereby plants manufacture carbohydrate from
succinate and oxaloacetate
In biological systems most energy generating redox reactions involve hydride ion transfer or hydrogen atom transfer using which of the following?
ADP and NADPH
Which of the following coenzymes function as an acetyl group carrier?
Acetly CoA
The first of two molecules of carbon dioxide is released from which of the following compounds in the citric acid cycle?
isocitrate, and alpha ketogluterate
The high energy molecule produced in the conversion of succinyl-CoA to succinate is which of the following?
GDP to GTP, ADP to ATP
Which of the following reactions is an anapldrotic reaction of the citric acid cycle?
oxaloacetate from pyruvate or aspartate, succinyl CoA from fatty acids
Oxygen is useful for energy generation because?
it is abundant and electronegative, making it a powerful oxidizing agent.
The most pivotal event in the history of life on earth is?
the emergence of the water splitting OEC of PSII, aerobic respiration
After the evolution of oxygenic photosynthesis the release of oxygen was not immediately followed by the accumulation of oxygen in the atmosphere. This was true because
O2 reacted with reduced molecules and ions, thus beginning the gradual transition from a reducing to an oxidizing environment
Obligate anaerobes are
organisms that grow only in the absence of O2 and use fermentation to generate energy
Facultative anaerobes
not only possess the biochemical mechanisms required for detoxifying ROS, but can also use O2 as an electron acceptor when gas is available
In eukaryotes citrate synthetase rate is controlled primarily by
availability of substrate molecule oxaloacetate