The Citric Acid Cycle Practice Test

These questions are part of the practice quiz. Start practicing

• In addition to NAD:NADH ratio, what is another factor that inhibits alpha-ketoglutarate dehydrogenase activity?
• Which two vitamins are important as cofactors in the Citric Acid Cycle?
• What drives the conversion of succinyl-CoA to succinate?
• Which molecule enters the Citric Acid Cycle after losing a carbon atom in the form of CO2?
• Which metabolic pathways are interconnected with the Citric Acid Cycle?
• What is the first substrate formed in the Citric Acid Cycle?
• What energy-carrying molecules are primarily produced during the Citric Acid Cycle?
• Which reactions replace citric acid cycle intermediates that are used for biosynthesis?
• How many NADH molecules are produced in one cycle of the Citric Acid Cycle?
• What role does CoA play in the Citric Acid Cycle?
• Which enzymes are primarily involved in the regulatory steps of the Citric Acid Cycle?
• Why is nitrogenous waste transferred to alanine?
• What is the process by which pyruvate transforms into acetyl CoA?
• What is the primary reason lactate is formed from pyruvate?
• Which intermediate is produced after the conversion of isocitrate in the Citric Acid Cycle?
• How many carbon atoms are present in citrate?
• What factor can inhibit the Citric Acid Cycle during high energy supply?
• How does the Citric Acid Cycle connect to glycolysis?
• What is the fate of pyruvate in aerobic conditions prior to entering the Citric Acid Cycle?
• What does succinate dehydrogenase do during the citric acid cycle?
• Which enzyme catalyzes the conversion of isocitrate to alpha-ketoglutarate?
• What does the term "anaplerotic" refer to in the context of the Citric Acid Cycle?
• What role do anapleurotic reactions play in metabolism?
• What is the net gain of NADH from one turn of the Citric Acid Cycle?
• Which molecule is produced as a byproduct of the Citric Acid Cycle?
• Which of the following is an intermediate in the citric acid cycle?
• In what form is energy primarily produced during the Citric Acid Cycle?
• What is the activity of isocitrate dehydrogenase increased by in muscle during exercise?
• During which step of the Citric Acid Cycle is FADH2 produced?
• Why is the Citric Acid Cycle considered a metabolic hub?
• How is FAD described as part of succinate dehydrogenase?
• What does GTP stand for and what is its function in the Citric Acid Cycle?
• What is citrate primarily used for in biosynthesis?
• Why are pyruvate and lactate levels elevated in individuals with pyruvate dehydrogenase deficiency?
• Which enzyme catalyzes the conversion of malate to oxaloacetate in the Citric Acid Cycle?
• What primarily regulates the citric acid cycle during the fed state?
• Which compound directly regulates the activity of the Citric Acid Cycle?
• What would be the consequence of a deficiency in succinate dehydrogenase?
• How many NADH molecules are produced per turn of the Citric Acid Cycle?
• Which reaction in the Citric Acid Cycle produces carbon dioxide?
• Which reaction transforms acetyl-CoA and oxaloacetate into citrate?
• Is the conversion of succinyl CoA to succinate by succinyl CoA synthetase reversible?
• Which enzyme is responsible for the conversion of succinyl CoA to succinate?
• How does the Citric Acid Cycle interlink with the urea cycle in mammals?
• When oxaloacetate concentration is low, what happens to acetyl CoA in the citric acid cycle?
• Which process cannot occur efficiently without pyruvate dehydrogenase?
• What is the role of succinyl CoA synthetase in the citric acid cycle?
• What enzyme catalyzes the conversion of citrate to isocitrate?
• What type of amino acids can be converted into ketone bodies?
• What is formed when succinyl-CoA is converted to succinate?
• What is the purpose of making alanine from pyruvate?
• Which compound is formed during the oxidative decarboxylation of isocitrate?
• What substrates are fed into the Citric Acid Cycle?
• Which compound in the citric acid cycle combines with acetyl CoA to initiate the cycle?
• What are anapleurotic reactions?
• How does the Citric Acid Cycle contribute to the metabolism of amino acids?
• Which of the following is a product of the Citric Acid Cycle that enters the electron transport chain?
• What is the regenerated compound of the citric acid cycle?
• What is the role of NADH and FADH2 produced in the Citric Acid Cycle?
• What compound is oxaloacetate notably used for in biosynthesis?
• What is the final product of the Citric Acid Cycle that is regenerated?
• What effect does an increase in ATP concentration have on Citric Acid Cycle activity?
• Which component acts as a coenzyme for the reactions in the Citric Acid Cycle?
• What is the end product of the Citric Acid Cycle per one acetyl-CoA molecule?
• What is the primary purpose of the Citric Acid Cycle?
• Which enzyme catalyzes the conversion of alpha-ketoglutarate to succinyl-CoA?
• What is the significance of the Citric Acid Cycle in cellular metabolism?
• Which compound is regenerated at the end of the Citric Acid Cycle to continue the cycle?
• Which of the following is an inhibitor of citrate synthase?
• Which molecules enter the Citric Acid Cycle?
• During fasting, what is the main regulation of the citric acid cycle?
• Which pathological condition is linked to enzyme deficiencies in the Citric Acid Cycle?
• During which conversion is FADH2 produced in the Citric Acid Cycle?
• Which enzyme is responsible for substrate-level phosphorylation in the citric acid cycle?
• Why is it important for succinate dehydrogenase to quickly oxidize its FADH2 prosthetic group?
• Which enzyme facilitates the conversion of malate back to oxaloacetate?
• During which process is GTP converted into ATP?
• What is the fate of ethanol in the context of the Citric Acid Cycle?
• Where is the Citric Acid Cycle primarily located in the cell?
• What main factor can enhance the activity of the citric acid cycle?
• What would be the consequence of an increase in the NAD:NADH ratio for isocitrate dehydrogenase activity?
• How do inhibitors such as malonate affect the Citric Acid Cycle?
• Which of the following is a main source of acetyl CoA?
• Why is the Citric Acid Cycle also referred to as the Krebs Cycle?
• What condition might arise from the excess accumulation of citrate?
• Which factor does citrate synthase activity depend on?
• What happens to the oxaloacetate molecule after it is formed in the Citric Acid Cycle?
• Which molecule acts as a key allosteric inhibitor of citrate synthase?
• What is the total ATP yield from one molecule of glucose after glycolysis and full oxidation in the Citric Acid Cycle?
• Which enzyme connects the Citric Acid Cycle to the electron transport chain?
• Which intermediate is not part of the Citric Acid Cycle?
• Which compound is an intermediary substrate formed from succinate during the cycle?
• What can pyruvate dehydrogenase deficiency potentially cause?
• Why is the conversion of pyruvate to oxaloacetate considered useful?
• What type of reaction involves the conversion of isocitrate to alpha-ketoglutarate?
• What type of reaction does aconitase facilitate?
• Where is succinate dehydrogenase embedded in the mitochondrion?
• Which cycle operates in the mitochondria of mammals under aerobic conditions?
• Name an enzyme involved in the conversion of fumarate to malate?
• How many carbon atoms are present in acetyl-CoA?
• What type of reaction does alpha-ketoglutarate dehydrogenase catalyze?
• How many molecules of NADH are produced directly from the citric acid cycle?
• What is the significance of acetyl-CoA in cellular respiration?
• What is the molecular formula of citric acid?
• How does the Citric Acid Cycle contribute to the metabolism of fatty acids?
• What is the primary action of citrate synthase in the citric acid cycle?
• What role does water play in the Citric Acid Cycle?
• Which metabolic pathway is responsible for regenerating oxaloacetate?
• During the citric acid cycle, which molecule is primarily responsible for transporting electrons?
• What is the function of aconitase in the Citric Acid Cycle?
• What is the source of electrons for the electron transport chain that follows the Citric Acid Cycle?
• What is alpha-ketoglutarate used for in biosynthesis?
• How is succinyl-CoA produced in the Citric Acid Cycle?
• How many times does the Citric Acid Cycle turn for one molecule of glucose?
• What is a common symptom of pyruvate dehydrogenase deficiency?
• How many CO2 molecules are produced in one turn of the Citric Acid Cycle?
• How many NADH are produced per glucose molecule during the Citric Acid Cycle?
• What does the excess citrate released from the citric acid cycle stimulate in the liver?
• What is a key regulatory point of the Citric Acid Cycle?
• What regulatory mechanism is primarily associated with isocitrate dehydrogenase?
• What is the critical consequence of low oxaloacetate levels in liver metabolism?
• What role does GTP or ATP play in the Citric Acid Cycle?
• How does the body regulate the citric acid cycle during intense exercise?
• What is succinate dehydrogenase also known as?
• How does the Citric Acid Cycle relate to gluconeogenesis?
• Which intermediate is formed directly after citrate in the Citric Acid Cycle?
• Which compound is regenerated at the end of the Citric Acid Cycle to continue the process?
• What is the main purpose of the Citric Acid Cycle in cellular metabolism?
• How does the Citric Acid Cycle help in the metabolism of fatty acids?
• What allosteric regulators activate the isocitrate dehydrogenase enzyme?
• What is the primary role of the Citric Acid Cycle in metabolism?
• What role does calcium play in the Citric Acid Cycle?
• What metabolic process is inhibited when Acetyl CoA supply is high?
• Which enzyme catalyzes the conversion of acetyl-CoA and oxaloacetate to citrate?
• Which of the following is not a product of the Citric Acid Cycle?
• In the liver, what causes inadequate levels of oxaloacetate that affects the citric acid cycle?
• Which compound is crucial for electron transport during the Citric Acid Cycle?
• Is succinate dehydrogenase a part of the citric acid cycle or the electron transport chain?
• Which enzyme catalyzes the conversion of isocitrate to alpha-ketoglutarate?
• In muscle during contraction, what enhances the activity of the citric acid cycle?
• Which of the following steps of the Citric Acid Cycle involves decarboxylation?
• What are the primary end products of the Citric Acid Cycle?
• Which compound is formed during the hydration of fumarate?
• What is the energy carrier molecule generated from succinyl-CoA?
• What is the end product of the reaction catalyzed by alpha-ketoglutarate dehydrogenase?
• What is the primary purpose of the Citric Acid Cycle?
• Which of the following compounds is formed first in the Citric Acid Cycle?
• How does exercise affect the activity of the Citric Acid Cycle?
• What type of reaction occurs when succinate is converted to fumarate in the Citric Acid Cycle?
• Which two high-energy electron carriers are generated through the cycle's reactions?
• Which enzyme is alpha-ketoglutarate dehydrogenase very similar to?
• Which intermediate can lead to the production of amino acids through transamination?
• What is another term for an amino acid that can be converted into glucose?
• Which vitamin is a precursor to NAD+?
• What is the primary purpose of the Citric Acid Cycle?
• What is the primary function of the Citric Acid Cycle in cellular metabolism?
• What is the importance of the electron transport chain in relation to the Citric Acid Cycle products?
• Why is neurological impairment associated with pyruvate dehydrogenase deficiency?
• What role does succinate dehydrogenase play in the Citric Acid Cycle?
• What is the effect of citrate on glycolysis when it accumulates in the cell?
• Which coenzyme is involved in the conversion of succinate to fumarate?
• What is released during the conversion of isocitrate to alpha-ketoglutarate?
• Which of the following intermediates is NOT part of the Citric Acid Cycle?
• Which reaction in the Citric Acid Cycle produces CO2 as a byproduct?
• Which molecule acts as the final electron acceptor in the electron transport chain that follows the Citric Acid Cycle?
• How many ATP molecules can be produced from one cycle of the citric acid cycle?
• What physiological state requires increased activity of the citric acid cycle for energy generation?
• Which of the following is NOT a common destination of pyruvate?
• What synthesizes Acetyl CoA primarily during fasting states in most tissues?
• What factors affect alpha-ketoglutarate dehydrogenase activity?
• Where are the electrons passed onto FAD from succinate dehydrogenase sent to?
• What are the main products of one turn of the Citric Acid Cycle?
• Which compounds are required for the synthesis of citrate?
• Which intermediate in the citric acid cycle is crucial for the biosynthesis of fatty acids?
• In which cellular organelle does the Citric Acid Cycle primarily occur?
• What provides the energy for substrate-level phosphorylation of GDP in the conversion of succinyl CoA to succinate?
• What is the main output of the Citric Acid Cycle in terms of ATP equivalents?
• In the Citric Acid Cycle, the conversion of fumarate to malate is catalyzed by which enzyme?
• What coenzymes are reduced during the Citric Acid Cycle?
• What happens to fetuses with pyruvate dehydrogenase deficiency in terms of weight gain?
• Which enzyme catalyzes the conversion of isocitrate to alpha-ketoglutarate?
• What effect do high levels of NADH have on the Citric Acid Cycle?
• Where are the rest of the enzymes in the citric acid cycle located?
• What is the primary purpose of the Citric Acid Cycle?
• What type of reaction is involved in the conversion of citrate to isocitrate?
• Which intermediate is produced after citrate during the Citric Acid Cycle?
• What is a common product of the Citric Acid Cycle used in biosynthesis?
• What is a potential consequence of inhibiting a key enzyme in the Citric Acid Cycle?
• Which hormone is responsible for stimulating the activity of the Citric Acid Cycle?
• What type of substrate-level phosphorylation occurs in the Citric Acid Cycle?
• How does pyruvate dehydrogenase deficiency generally affect physical development?
• What are the alternative names for the Citric Acid Cycle?
• Which enzyme is responsible for the conversion of isocitrate into alpha-ketoglutarate?
• What coenzymes are reduced during the citric acid cycle?
• What role do NADH and FADH2 play in cellular respiration?
• Which compound is regenerated at the end of the Citric Acid Cycle?
• Which of the following is a factor affecting isocitrate dehydrogenase activity?
• How many molecules of CO2 are produced directly from the citric acid cycle?
• In which part of the cell does the Citric Acid Cycle occur?
• Which of the following reactions is part of the Citric Acid Cycle?
• Which molecule enters the Citric Acid Cycle at the beginning to initiate the process?
• Which step of the Citric Acid Cycle is considered a key regulatory point?
• What role does citrate play in the metabolism of glucose?
• What role does the ADP:ATP ratio play in the citric acid cycle?
• What is malate primarily used for in biosynthesis?
• How many ATP molecules can be produced from one molecule of FADH2?
• How can the cycle contribute to gluconeogenesis?
• What purpose does the maleate intermediate serve in the Citric Acid Cycle?
• In the context of citric acid cycle intermediates, which compound is specifically involved in the regulation of metabolic pathways?
• Which enzymes are affected by elevated ATP levels?
• What two carbons are lost as CO2 during the complete oxidation of glucose in the Citric Acid Cycle?
• Which cycle is also known as the Krebs cycle?
• What is the primary purpose of the citric acid cycle?
• What effect does a high concentration of intermediates have on the citric acid cycle?
• When citrate accumulates, what can it be converted into?
• Under what condition is Acetyl CoA primarily produced from pyruvate?
• What compounds are synthesized from succinyl CoA?
• How many times does the Citric Acid Cycle turn for each molecule of glucose?
• What reaction type occurs when isocitrate is converted to alpha-ketoglutarate?
• What is the consequence of an increased NADH/NAD+ ratio in the cell?
• Which component of the Citric Acid Cycle directly contributes electrons to the electron transport chain?
• What coenzymes are required for the alpha-ketoglutarate dehydrogenase reaction?
• How do citric acid cycle intermediates play a role in photosynthesis?
• Which compound is produced by the Citric Acid Cycle as a waste product?
• What is the primary purpose of the Citric Acid Cycle?
• What enables the citric acid cycle to increase or decrease its rate as needed by the cell?
• What type of metabolism does the Citric Acid Cycle primarily represent?
• What is the role of acetyl-CoA in the Citric Acid Cycle?
• What key molecule exits the cycle and feeds into the electron transport chain?
• Which of the following is NOT a key enzyme of the citric acid cycle?
• Which enzyme in the Citric Acid Cycle is directly activated by calcium ions (Ca2+)?
• What compound is produced during the conversion of succinyl-CoA to succinate?
• What can oxaloacetate made from pyruvate be used for?
• In which part of the cell does the Citric Acid Cycle occur?
• Which molecule is produced as a byproduct during the conversion of citrate to isocitrate?
• What type of reaction does isocitrate dehydrogenase catalyze?
• What is the significance of FADH2 generated during the Citric Acid Cycle?
• What is the main function of isocitrate dehydrogenase in the citric acid cycle?
• What important metabolic checkpoint occurs at the conversion of succinyl-CoA to succinate?
• What is the function of citrate synthase in the Citric Acid Cycle?
• How many ATP molecules can be generated from one molecule of NADH?
• What type of reaction is the conversion of pyruvate to acetyl CoA?
• What property of pyruvate is lost during the oxidative decarboxylation?
• What behavioral change is expected in a patient with elevated lactate levels?
• Which reaction in the Citric Acid Cycle requires the input of Coenzyme A?
• When is lactate produced from pyruvate?
• What role does Acetyl CoA play in the body?
• What compound is produced from malate in the Citric Acid Cycle?
• What substance is produced in the Citric Acid Cycle that can also serve as a precursor for fatty acid synthesis?
• What type of reaction does pyruvate carboxylase catalyze?
• What type of bond is broken to release energy during the conversion of succinyl CoA to succinate?
• What is produced in addition to ATP during the Citric Acid Cycle?
• Which of the following is generated during one turn of the Citric Acid Cycle and can be used for energy?
• During which reaction does alpha-ketoglutarate dehydrogenase convert alpha-ketoglutarate?