Exam 4 ch. 23 Citric Acid Cycle Flashcards
The ___ ___ ___ is a series of reactions that connects the intermediate acetyl CoA from the catabolic pathways in stage 2 with electron transport and the synthesis of ATP in stage 3
Citric Acid Cycle
The Citric Acid Cycle:
operates under (aerobic or anaerobic) conditions
Aerobic
The Citric Acid Cycle:
oxidizes the two-carbon acetyl group in acetyl CoA to ___
CO2
The Citric Acid Cycle:
produces reduced coenzymes ___ and ___
NADH and FADH2
The Citric Acid Cycle:
is named for the six-carbon citrate ion from citric acid (C6H8O7), a ___ __, formed in the first reaction
Tricarboxylic acid
In the citric acid cycle,
six carbons move through the citric acid cycle, producing ____ and 2CO2
Oxaloacetate
In the citric acid cycle, each turn contains __(#) oxidation reactions producing the reduced coenzymes NADH and FADH2.
Four
In the citric acid cycle, one ___ (converted to ___ in the cell) is produced during the citric acid cycle
GTP (converted to ATP)
In the citric acid cycle, ___ (#) reactions oxidize acetyl CoA from ____ or fatty acids, producing CO2 and the high-energy compounds FADH2, NADH, and GTP
In the citric acid cycle, eight reactions oxidize acetyl CoA from pyruvate or fatty acids, producing CO2 and the high-energy compounds FADH2, NADH, and GTP
Reactions involved in the citric acid cycle include condensation, dehydration, hydration, oxidation, reduction, and hydrolysis
Citric Acid Cycle reactions:
Reaction 1:
In the first reaction of the citric acid cycle,
citrate synthase catalyzes the _____ of an acetyl group (2C) from acetyl CoA with oxaloacetate (4C) to yield ____ and ____
In the first reaction of the citric acid cycle,
citrate synthase catalyzes the condensation of an acetyl group (2C) from acetyl CoA with oxaloacetate (4C) to yield citrate (6C) and coenzyme A
Reaction 1:
In the first reaction fo the citric acid cycle, the energy to form citrate is provided by the _____ of the high-energy thioester bond in acetyl CoA
the energy to form citrate is provided by the hydrolysis of the high-energy thioester bond in acetyl CoA
Reaction 1:
In the first reaction fo the citric acid cycle, the energy to form citrate is provided by the _____ of the high-energy thioester bond in acetyl CoA
Reaction 1:
In the first reaction fo the citric acid cycle, the energy to form citrate is provided by the hydrolysis of the high-energy thioester bond in acetyl CoA
Reaction 2: Isomerazation
In reaction 2 of the citric acid cycle, aconitase catalyzes the ____ of citrate (tertiary alcohol) to yield cis-aconitate, followed by a ____ that forms isocitrate
In reaction 2 of the citric acid cycle, aconitase catalyzes the dehydration of citrate (tertiary alcohol) to yield cis-aconitate, followed by a hydration that forms isocitrate.
In reaction 2 of the citric acid cycle, aconitase catalyzes the ____ of citrate (tertiary alcohol) to yield cis-aconitate, followed by a ____ that forms isocitrate
In reaction 2 of the citric acid cycle, aconitase catalyzes the dehydration of citrate (tertiary alcohol) to yield cis-aconitate, followed by a hydration that forms isocitrate.
In reaction 3, isocitrate undergoes decarboxylation by isocitrate dehydrogenase.
One carbon is removed by converting a ___ ___ to CO2
In reaction 3, isocitrate undergoes decarboxylation by isocitrate dehydrogenase.
One carbon is removed by converting a carboxylate group (COO−) to CO2
In reaction 3, isocitrate undergoes decarboxylation by isocitrate dehydrogenase.
The ____ removes hydrogen ions and electrons, used to reduce NAD+ to NADH and H+.
In reaction 3, isocitrate undergoes decarboxylation by isocitrate dehydrogenase.
The dehydrogenase removes hydrogen ions and electrons, used to reduce NAD+ to NADH and H
In reaction 4, catalyzed by α-ketoglutarate dehydrogenase, α-ketoglutarate (5C) undergoes ____ to yield (4C) succinyl CoA.
In reaction 4, catalyzed by α-ketoglutarate dehydrogenase, α-ketoglutarate (5C) undergoes decarboxylation to yield (4C) succinyl CoA.
In reaction 4, catalyzed by α-ketoglutarate dehydrogenase,
____ of the thiol group (—SH) in HS—CoA provides hydrogen that is transferred to NAD+ to form a second molecule of NADH and H+.
In reaction 4, catalyzed by α-ketoglutarate dehydrogenase, oxidation of the thiol group (—SH) in HS—CoA provides hydrogen that is transferred to NAD+ to form a second molecule of NADH and H+.
In reaction 5, catalyzed by succinyl CoA synthetase, hydrolysis of the ___ ___ in succinyl CoA yields succinate and HS—CoA.
In reaction 5, catalyzed by succinyl CoA synthetase, hydrolysis of the thioester bond in succinyl CoA yields succinate and HS—CoA.
In reaction 5, catalyzed by succinyl CoA synthetase, energy from hydrolysis is transferred to the ____ of phosphate and GDP forming ___, a high-energy compound similar to ATP
In reaction 5, catalyzed by succinyl CoA synthetase, energy from hydrolysis is transferred to the condensation of phosphate and GDP forming GTP, a high-energy compound similar to ATP
In reaction 6, catalyzed by succinate dehydrogenase, succinate is ____ to fumarate, a compound with a C = C bond.
In reaction 6, catalyzed by succinate dehydrogenase, succinate is oxidized to fumarate, a compound with a C=C bond.
In reaction 6, catalyzed by succinate dehydrogenase, 2H lost from succinate are used to reduce the coenzyme ___ to ___
In reaction 6, catalyzed by succinate dehydrogenase, 2H lost from succinate are used to reduce the coenzyme FAD to FADH2
In reaction 7, catalyzed by fumarase, ___ is added to the double bond of fumarate to yield malate, a ___ ___
In reaction 7, catalyzed by fumarase, water is added to the double bond of fumarate to yield malate, a secondary alcohol
In reaction 8, catalyzed by malate dehydrogenase, the hydroxyl group in malate is ____ to a carbonyl group, yielding oxaloacetate.
In reaction 8, catalyzed by malate dehydrogenase,
the hydroxyl group in malate is oxidized to a carbonyl group, yielding oxaloacetate.
In reaction 8, catalyzed by malate dehydrogenase,
oxidation provides hydrogen ions and electrons for the ____ of NAD+ to NADH and H+.
In reaction 8, catalyzed by malate dehydrogenase,
oxidation provides hydrogen ions and electrons for the reduction of NAD+ to NADH and H+.
Reaction 1: Formation of
R1: Formation of Citrate
Reaction 2:
R2: Isomerization
Reaction 3:
R3: Oxidation, Decarboxylation
Reaction 4:
R4: Decarboxylation, Oxidation