Krebs Cycle - MCAT Biological and Biochemical Foundations of Living Systems
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Within the Krebs cycle, L-malate and NAD+ come together to form oxaloacetate, NADH, and H+. What type of chemical reaction is responsible for this step in the cycle?
Within the Krebs cycle, L-malate and NAD+ come together to form oxaloacetate, NADH, and H+. What type of chemical reaction is responsible for this step in the cycle?
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In order for oxaloacetate to be formed, malate must lose electrons, which is the definition of an oxidation reaction. Alternately, NAD+ is reduced (gains electrons) to form NADH and H+.
In order for oxaloacetate to be formed, malate must lose electrons, which is the definition of an oxidation reaction. Alternately, NAD+ is reduced (gains electrons) to form NADH and H+.
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During cellular respiration, where is NADH produced?
During cellular respiration, where is NADH produced?
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NADH is produced during glycolysis, which occurs in the cytoplasm. NADH is also produced during the Krebs cycle, which occurs in the mitochondrial matrix. The protons generated in the production of NADH are later used in the intermembrane space to power ATP synthase during oxidative phosphorylation.
NADH is produced during glycolysis, which occurs in the cytoplasm. NADH is also produced during the Krebs cycle, which occurs in the mitochondrial matrix. The protons generated in the production of NADH are later used in the intermembrane space to power ATP synthase during oxidative phosphorylation.
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If the Krebs cycle is overstimulated, the body will produce too much of which of the following molecules?
If the Krebs cycle is overstimulated, the body will produce too much of which of the following molecules?
Tap to reveal answer
Of the answer choices, only carbon dioxide is a product of the Krebs cycle. If the cycle is overstimulated, too much of the products will be formed and the body will have too much carbon dioxide.
Glucose is the reactant that fuels glycolysis to produce pyruvate, which is then converted to acetyl CoA for the Krebs cycle. As such, each of these would be depleted as reactants fueling an overstimulation of the Krebs cycle.
Of the answer choices, only carbon dioxide is a product of the Krebs cycle. If the cycle is overstimulated, too much of the products will be formed and the body will have too much carbon dioxide.
Glucose is the reactant that fuels glycolysis to produce pyruvate, which is then converted to acetyl CoA for the Krebs cycle. As such, each of these would be depleted as reactants fueling an overstimulation of the Krebs cycle.
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Where is the Krebs cycle carried out in eukaryotic cells?
Where is the Krebs cycle carried out in eukaryotic cells?
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During the Krebs cycle, or citric acid cycle, acetyl CoA is oxidized to CO2 and NAD+ and FADH are reduced to NADH and FADH2, respectively. This process is carried out in the mitochondrial matrix of eukaryotic cells.
The electron transport chain is carried out in the inner membrane of the mitochondria, while glycolysis is carried out in the cytosol.
During the Krebs cycle, or citric acid cycle, acetyl CoA is oxidized to CO2 and NAD+ and FADH are reduced to NADH and FADH2, respectively. This process is carried out in the mitochondrial matrix of eukaryotic cells.
The electron transport chain is carried out in the inner membrane of the mitochondria, while glycolysis is carried out in the cytosol.
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Cellular respiration is the set of metabolic reactions that occur in cells to produce energy in the form of ATP. During cellular respiration, high energy intermediates are created that can then be oxidized to make ATP. During what stage are these intermediates produced?
Cellular respiration is the set of metabolic reactions that occur in cells to produce energy in the form of ATP. During cellular respiration, high energy intermediates are created that can then be oxidized to make ATP. During what stage are these intermediates produced?
Tap to reveal answer
The citric acid (Krebs) cycle and glycolysis yield high energy intermediates that can then be used to make ATP. Each turn of the citric acid cycle generates NADH and FADH2, and each cycle of glycolysis generates NADH. These intermediates can then donate their electrons and become oxidized in the electron transport chain. Production of these electron donors is essential to the function of the electron transport chain.
The citric acid (Krebs) cycle and glycolysis yield high energy intermediates that can then be used to make ATP. Each turn of the citric acid cycle generates NADH and FADH2, and each cycle of glycolysis generates NADH. These intermediates can then donate their electrons and become oxidized in the electron transport chain. Production of these electron donors is essential to the function of the electron transport chain.
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Acetyl-CoA is a react in the citric acid cycle, while 
and 
are products. If twelve molecules of 
are produced over a period of time, how many 
molecules are produced during this period?
Acetyl-CoA is a react in the citric acid cycle, while
Tap to reveal answer
Each turn of the citric acid cycle is powered by one molecule of acetyl-CoA, resulting in three 
and one 
. The net reaction is:
Since twelve 
are produced, there must have been an input of four acetyl-CoA molecules and four total turns in the cycle. As a result, four 
molecules were produced.
Each turn of the citric acid cycle is powered by one molecule of acetyl-CoA, resulting in three
Since twelve
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Which statement is false regarding the citric acid cycle?
Which statement is false regarding the citric acid cycle?
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Oxygen is needed for the electron transport chain to occur which oxidizes 
and 
. If there is no oxygen available then Krebs cycle would not occur since there would be no oxidized electron carriers. Therefore oxygen is only indirectly required for the Krebs cycle to occur, not directly.
Oxygen is needed for the electron transport chain to occur which oxidizes
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James took a neural sample and separated the cell body from the axon. He noticed that when he placed both parts on a glucose plate, the cell body began releasing carbon dioxide. What could explain the result?
James took a neural sample and separated the cell body from the axon. He noticed that when he placed both parts on a glucose plate, the cell body began releasing carbon dioxide. What could explain the result?
Tap to reveal answer
The cell body of a neuron is where the mitochondria and all other organelles are located. Recall from the Krebs cycle that carbon dioxide is produced as a byproduct. Anaerobic respiration, which occurs in the cytoplasm does not release carbon dioxide (in humans) and produces lactic acid instead. Note that in certain organisms like yeast, fermentation produces ethanol (two-carbons) and carbon dioxide since pyruvate, the product of glycolysis is a three-carbon molecule.
The cell body of a neuron is where the mitochondria and all other organelles are located. Recall from the Krebs cycle that carbon dioxide is produced as a byproduct. Anaerobic respiration, which occurs in the cytoplasm does not release carbon dioxide (in humans) and produces lactic acid instead. Note that in certain organisms like yeast, fermentation produces ethanol (two-carbons) and carbon dioxide since pyruvate, the product of glycolysis is a three-carbon molecule.
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During cellular respiration, where is NADH produced?
During cellular respiration, where is NADH produced?
Tap to reveal answer
NADH is produced during glycolysis, which occurs in the cytoplasm. NADH is also produced during the Krebs cycle, which occurs in the mitochondrial matrix. The protons generated in the production of NADH are later used in the intermembrane space to power ATP synthase during oxidative phosphorylation.
NADH is produced during glycolysis, which occurs in the cytoplasm. NADH is also produced during the Krebs cycle, which occurs in the mitochondrial matrix. The protons generated in the production of NADH are later used in the intermembrane space to power ATP synthase during oxidative phosphorylation.
← Didn't Know|Knew It →
Within the Krebs cycle, L-malate and NAD+ come together to form oxaloacetate, NADH, and H+. What type of chemical reaction is responsible for this step in the cycle?
Within the Krebs cycle, L-malate and NAD+ come together to form oxaloacetate, NADH, and H+. What type of chemical reaction is responsible for this step in the cycle?
Tap to reveal answer
In order for oxaloacetate to be formed, malate must lose electrons, which is the definition of an oxidation reaction. Alternately, NAD+ is reduced (gains electrons) to form NADH and H+.
In order for oxaloacetate to be formed, malate must lose electrons, which is the definition of an oxidation reaction. Alternately, NAD+ is reduced (gains electrons) to form NADH and H+.
← Didn't Know|Knew It →
If the Krebs cycle is overstimulated, the body will produce too much of which of the following molecules?
If the Krebs cycle is overstimulated, the body will produce too much of which of the following molecules?
Tap to reveal answer
Of the answer choices, only carbon dioxide is a product of the Krebs cycle. If the cycle is overstimulated, too much of the products will be formed and the body will have too much carbon dioxide.
Glucose is the reactant that fuels glycolysis to produce pyruvate, which is then converted to acetyl CoA for the Krebs cycle. As such, each of these would be depleted as reactants fueling an overstimulation of the Krebs cycle.
Of the answer choices, only carbon dioxide is a product of the Krebs cycle. If the cycle is overstimulated, too much of the products will be formed and the body will have too much carbon dioxide.
Glucose is the reactant that fuels glycolysis to produce pyruvate, which is then converted to acetyl CoA for the Krebs cycle. As such, each of these would be depleted as reactants fueling an overstimulation of the Krebs cycle.
← Didn't Know|Knew It →
Where is the Krebs cycle carried out in eukaryotic cells?
Where is the Krebs cycle carried out in eukaryotic cells?
Tap to reveal answer
During the Krebs cycle, or citric acid cycle, acetyl CoA is oxidized to CO2 and NAD+ and FADH are reduced to NADH and FADH2, respectively. This process is carried out in the mitochondrial matrix of eukaryotic cells.
The electron transport chain is carried out in the inner membrane of the mitochondria, while glycolysis is carried out in the cytosol.
During the Krebs cycle, or citric acid cycle, acetyl CoA is oxidized to CO2 and NAD+ and FADH are reduced to NADH and FADH2, respectively. This process is carried out in the mitochondrial matrix of eukaryotic cells.
The electron transport chain is carried out in the inner membrane of the mitochondria, while glycolysis is carried out in the cytosol.
← Didn't Know|Knew It →
Cellular respiration is the set of metabolic reactions that occur in cells to produce energy in the form of ATP. During cellular respiration, high energy intermediates are created that can then be oxidized to make ATP. During what stage are these intermediates produced?
Cellular respiration is the set of metabolic reactions that occur in cells to produce energy in the form of ATP. During cellular respiration, high energy intermediates are created that can then be oxidized to make ATP. During what stage are these intermediates produced?
Tap to reveal answer
The citric acid (Krebs) cycle and glycolysis yield high energy intermediates that can then be used to make ATP. Each turn of the citric acid cycle generates NADH and FADH2, and each cycle of glycolysis generates NADH. These intermediates can then donate their electrons and become oxidized in the electron transport chain. Production of these electron donors is essential to the function of the electron transport chain.
The citric acid (Krebs) cycle and glycolysis yield high energy intermediates that can then be used to make ATP. Each turn of the citric acid cycle generates NADH and FADH2, and each cycle of glycolysis generates NADH. These intermediates can then donate their electrons and become oxidized in the electron transport chain. Production of these electron donors is essential to the function of the electron transport chain.
← Didn't Know|Knew It →
Acetyl-CoA is a react in the citric acid cycle, while and are products. If twelve molecules of are produced over a period of time, how many molecules are produced during this period?
Acetyl-CoA is a react in the citric acid cycle, while
Tap to reveal answer
Each turn of the citric acid cycle is powered by one molecule of acetyl-CoA, resulting in three and one . The net reaction is:
Since twelve are produced, there must have been an input of four acetyl-CoA molecules and four total turns in the cycle. As a result, four molecules were produced.
Each turn of the citric acid cycle is powered by one molecule of acetyl-CoA, resulting in three
Since twelve
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Which statement is false regarding the citric acid cycle?
Which statement is false regarding the citric acid cycle?
Tap to reveal answer
Oxygen is needed for the electron transport chain to occur which oxidizes and . If there is no oxygen available then Krebs cycle would not occur since there would be no oxidized electron carriers. Therefore oxygen is only indirectly required for the Krebs cycle to occur, not directly.
Oxygen is needed for the electron transport chain to occur which oxidizes
← Didn't Know|Knew It →
James took a neural sample and separated the cell body from the axon. He noticed that when he placed both parts on a glucose plate, the cell body began releasing carbon dioxide. What could explain the result?
James took a neural sample and separated the cell body from the axon. He noticed that when he placed both parts on a glucose plate, the cell body began releasing carbon dioxide. What could explain the result?
Tap to reveal answer
The cell body of a neuron is where the mitochondria and all other organelles are located. Recall from the Krebs cycle that carbon dioxide is produced as a byproduct. Anaerobic respiration, which occurs in the cytoplasm does not release carbon dioxide (in humans) and produces lactic acid instead. Note that in certain organisms like yeast, fermentation produces ethanol (two-carbons) and carbon dioxide since pyruvate, the product of glycolysis is a three-carbon molecule.
The cell body of a neuron is where the mitochondria and all other organelles are located. Recall from the Krebs cycle that carbon dioxide is produced as a byproduct. Anaerobic respiration, which occurs in the cytoplasm does not release carbon dioxide (in humans) and produces lactic acid instead. Note that in certain organisms like yeast, fermentation produces ethanol (two-carbons) and carbon dioxide since pyruvate, the product of glycolysis is a three-carbon molecule.
← Didn't Know|Knew It →
During cellular respiration, where is NADH produced?
During cellular respiration, where is NADH produced?
Tap to reveal answer
NADH is produced during glycolysis, which occurs in the cytoplasm. NADH is also produced during the Krebs cycle, which occurs in the mitochondrial matrix. The protons generated in the production of NADH are later used in the intermembrane space to power ATP synthase during oxidative phosphorylation.
NADH is produced during glycolysis, which occurs in the cytoplasm. NADH is also produced during the Krebs cycle, which occurs in the mitochondrial matrix. The protons generated in the production of NADH are later used in the intermembrane space to power ATP synthase during oxidative phosphorylation.
← Didn't Know|Knew It →
Within the Krebs cycle, L-malate and NAD+ come together to form oxaloacetate, NADH, and H+. What type of chemical reaction is responsible for this step in the cycle?
Within the Krebs cycle, L-malate and NAD+ come together to form oxaloacetate, NADH, and H+. What type of chemical reaction is responsible for this step in the cycle?
Tap to reveal answer
In order for oxaloacetate to be formed, malate must lose electrons, which is the definition of an oxidation reaction. Alternately, NAD+ is reduced (gains electrons) to form NADH and H+.
In order for oxaloacetate to be formed, malate must lose electrons, which is the definition of an oxidation reaction. Alternately, NAD+ is reduced (gains electrons) to form NADH and H+.
← Didn't Know|Knew It →
If the Krebs cycle is overstimulated, the body will produce too much of which of the following molecules?
If the Krebs cycle is overstimulated, the body will produce too much of which of the following molecules?
Tap to reveal answer
Of the answer choices, only carbon dioxide is a product of the Krebs cycle. If the cycle is overstimulated, too much of the products will be formed and the body will have too much carbon dioxide.
Glucose is the reactant that fuels glycolysis to produce pyruvate, which is then converted to acetyl CoA for the Krebs cycle. As such, each of these would be depleted as reactants fueling an overstimulation of the Krebs cycle.
Of the answer choices, only carbon dioxide is a product of the Krebs cycle. If the cycle is overstimulated, too much of the products will be formed and the body will have too much carbon dioxide.
Glucose is the reactant that fuels glycolysis to produce pyruvate, which is then converted to acetyl CoA for the Krebs cycle. As such, each of these would be depleted as reactants fueling an overstimulation of the Krebs cycle.
← Didn't Know|Knew It →
Where is the Krebs cycle carried out in eukaryotic cells?
Where is the Krebs cycle carried out in eukaryotic cells?
Tap to reveal answer
During the Krebs cycle, or citric acid cycle, acetyl CoA is oxidized to CO2 and NAD+ and FADH are reduced to NADH and FADH2, respectively. This process is carried out in the mitochondrial matrix of eukaryotic cells.
The electron transport chain is carried out in the inner membrane of the mitochondria, while glycolysis is carried out in the cytosol.
During the Krebs cycle, or citric acid cycle, acetyl CoA is oxidized to CO2 and NAD+ and FADH are reduced to NADH and FADH2, respectively. This process is carried out in the mitochondrial matrix of eukaryotic cells.
The electron transport chain is carried out in the inner membrane of the mitochondria, while glycolysis is carried out in the cytosol.
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