Glycolysis And Krebs' Cycle Quiz
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Do you understand chemical compounds and their reactions well? Take this quiz on Glycolysis and Krebs' cycle, and see how much you know. Here, in this quiz, we have questions about these two topics so that you can practice and test your knowledge. This quiz will test your knowledge and enhance it with many new facts. If you know these topics well, it will be an easy quiz for you. All the best! Try to get a 100% score on this quiz.
Questions and Answers
- 1.
In the reaction: Citrate --> Isocitrate, the enzyme is an _____________________.
- A.
Isomerase
- B.
Pyruvate
- C.
Kinase
- D.
Diphosphate
Correct Answer
A. IsomeraseExplanation
Isomerases are enzymes that catalyze the structural rearrangement of isomers (molecules with the same molecular formula but different structural formulas). In the conversion of citrate to isocitrate, the enzyme aconitase acts as an isomerase, facilitating the rearrangement of the hydroxyl group within the molecule.Rate this question:
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- 2.
Glucose 6 Phosphate is converted to Fructose 6 Phosphate by an ______________________ enzyme.
- A.
Hydrase
- B.
Isomerase
- C.
Kinase
- D.
Pyruvate
Correct Answer
B. IsomeraseExplanation
The enzyme responsible for converting Glucose 6 Phosphate to Fructose 6 Phosphate is an isomerase. Isomerases catalyze the rearrangement of atoms within a molecule to convert it into an isomer of the original molecule. In this case, the isomerase enzyme facilitates the conversion of glucose 6 phosphate to fructose 6 phosphate by rearranging the atoms within the molecule.Rate this question:
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- 3.
Fructose 6 Phosphate gains a second phosphate to become Fructose 1,6 diphosphate. This reaction is catalyze by a ____________________ enzyme.
- A.
Kinase
- B.
Dephosphorylation
- C.
Hydrase
- D.
Pyruvate
Correct Answer
A. KinaseExplanation
Fructose 6 Phosphate gains a second phosphate to become Fructose 1,6 diphosphate. This reaction is catalyzed by a kinase enzyme. Kinases are enzymes that catalyze the transfer of a phosphate group from a high-energy molecule, such as ATP, to a substrate molecule. In this case, the kinase enzyme transfers a phosphate group from ATP to Fructose 6 Phosphate, resulting in the formation of Fructose 1,6 diphosphate.Rate this question:
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- 4.
Fructose 1,6 diphosphate encounters the enzyme Aldolase and undergoes a __________________ reaction, forming DHAP and PGAL.
- A.
Cleavage
- B.
Oxidation
- C.
Redox
- D.
Reduction
Correct Answer
A. CleavageExplanation
Fructose 1,6 diphosphate undergoes a cleavage reaction when it encounters the enzyme Aldolase. This reaction results in the formation of DHAP and PGAL.Rate this question:
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- 5.
DHAP is not a reactant in glycolysis beyond reaction #4, so in reaction #5 of Glycolysis it is converted to ___________.
- A.
Dephosphorylation
- B.
PGAL, phosphoglyceraldehyde
- C.
Isomerization
- D.
NADPH
Correct Answer
B. PGAL, phosphoglyceraldehydeExplanation
In reaction #5 of glycolysis, DHAP is converted to PGAL, phosphoglyceraldehyde. This is because DHAP is an intermediate product in glycolysis and is not a reactant beyond reaction #4. The conversion of DHAP to PGAL is important for the continuation of the glycolytic pathway.Rate this question:
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- 6.
If you see this in a reaction: NAD+ ------> NADH Then the reaction is a ____________ reaction
- A.
Exothermic
- B.
Redox, oxidation, reduction
- C.
Endothermic
- D.
None of the above
Correct Answer
B. Redox, oxidation, reductionExplanation
The given reaction shows the conversion of NAD+ to NADH, indicating a transfer of electrons. This is characteristic of a redox reaction, which involves both oxidation (loss of electrons) and reduction (gain of electrons). Therefore, the correct answer is redox, oxidation, reduction.Rate this question:
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- 7.
1,3 DPGA loses a phosphate to become 3 PGA. This is a __________________________ reaction.
- A.
Dephosphorylation
- B.
Polyphosphorylation
- C.
Oxidation
- D.
None of the above
Correct Answer
A. DephosphorylationExplanation
The correct answer is dephosphorylation. This is because the reaction involves the removal of a phosphate group from 1,3 DPGA, resulting in the formation of 3 PGA.Rate this question:
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- 8.
3 PGA has its phosphate group moved to Carbon #2, forming 2 PGA. This very simple reaction is an _______________________ reaction.
- A.
Polymerisaion
- B.
Isomerization
- C.
Dimerism
- D.
None of the above
Correct Answer
B. IsomerizationExplanation
The given correct answer is isomerization. Isomerization refers to the rearrangement of atoms within a molecule, resulting in the formation of isomers. In this case, the phosphate group in PGA is moved from Carbon #3 to Carbon #2, resulting in the formation of 2 PGA molecules. This rearrangement of atoms qualifies as an isomerization reaction.Rate this question:
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- 9.
The addition of H2O (or, H-OH) to the bonds in 2PGA results in the formation of ________________________.
- A.
3PGA
- B.
PEP, phosphoenolpyruvate
- C.
Isomerism
- D.
None of the above
Correct Answer
A. 3PGAExplanation
The addition of H2O (or, H-OH) to the bonds in 2-phosphoglycerate (2PGA) specifically results in the formation of 3-phosphoglycerate (3PGA). This reaction is catalyzed by the enzyme enolase and involves a simple rearrangement where water is added, and the phosphate group shifts from the second carbon (C2) to the third carbon (C3) of the glycerate backbone. This step is part of the Calvin cycle in photosynthesis and glycolysis in cellular respiration.Rate this question:
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- 10.
The addition of H2O (or, H-OH) to the bonds in 2PGA happens by way of a ________________ reaction.
- A.
Amylase
- B.
Hydration
- C.
Pyruvate
- D.
None of the above
Correct Answer
B. HydrationExplanation
The addition of H2O (or, H-OH) to the bonds in 2PGA happens by way of a hydration reaction.Rate this question:
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- 11.
The addition of H2O (or, H-OH) to the bonds in 2PGA happens because of a ________________ enzyme.
- A.
Kinase
- B.
Hydrase
- C.
Lipase
- D.
None of the above
Correct Answer
B. HydraseExplanation
The addition of H2O (or, H-OH) to the bonds in 2PGA happens because of a hydrase enzyme. This enzyme facilitates the hydrolysis reaction, breaking the bonds between the molecules of 2PGA and allowing the addition of water. This process is important in various biological reactions, including the breakdown of molecules and the synthesis of new compounds.Rate this question:
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- 12.
Because it is Linear, Glycolysis is considered to be a metabolic _________________.
- A.
Linear
- B.
Parallel
- C.
Cascade
- D.
Exponential
Correct Answer
A. LinearExplanation
Glycolysis is considered to be a metabolic linear process because it involves a sequential series of reactions where each reaction is dependent on the previous one. The substrates are converted into products through a step-by-step pathway, with each reaction being catalyzed by a specific enzyme. There are no branches or alternative pathways in glycolysis, making it a linear metabolic process.Rate this question:
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- 13.
Glycolysis occurs in the __________________ of the cell.
- A.
Mitochondria
- B.
Cell
- C.
Cytoplasm
- D.
None of the above
Correct Answer
C. CytoplasmExplanation
Glycolysis is the process in which glucose is broken down into pyruvate to produce energy. It occurs in the cytoplasm of the cell. The cytoplasm is the fluid-filled region of the cell that surrounds the organelles, including the mitochondria. While the mitochondria play a crucial role in cellular respiration, which is the next step in energy production after glycolysis, glycolysis itself takes place in the cytoplasm. Therefore, the correct answer is cytoplasm.Rate this question:
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- 14.
Krebs' Cycle occurs in the ___________________ of the cell
- A.
Membrane
- B.
Cytoplasm
- C.
Mitochondrion, mitochondria, mitochondrial matrix
- D.
None of the above
Correct Answer
C. Mitochondrion, mitochondria, mitochondrial matrixExplanation
The correct answer is mitochondrion, mitochondria, mitochondrial matrix. Krebs' Cycle, also known as the citric acid cycle, is a series of chemical reactions that occur in the mitochondria of the cell. It is an important part of cellular respiration, where glucose is broken down to produce energy in the form of ATP. The mitochondrion is the powerhouse of the cell and is responsible for generating most of the cell's energy through processes like the Krebs' Cycle. The cycle takes place in the mitochondrial matrix, which is the innermost compartment of the mitochondrion.Rate this question:
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- 15.
The portion of the mitochondrion that contains the enzymes required for Krebs' Cycle is the __________.
- A.
Cell
- B.
Matrix, mitochondrial matrix
- C.
Cytoplasm
- D.
Membrane
Correct Answer
B. Matrix, mitochondrial matrixExplanation
The correct answer is matrix, mitochondrial matrix. The mitochondrion is a double-membraned organelle found in eukaryotic cells. It is responsible for producing energy in the form of ATP through cellular respiration. The Krebs' Cycle, also known as the citric acid cycle, is a series of chemical reactions that occur in the matrix of the mitochondrion. This is where the enzymes required for the Krebs' Cycle are located, allowing for the production of ATP through the breakdown of glucose and other molecules.Rate this question:
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- 16.
The end product of glycolysis will be two molecules of ___________________.
- A.
Pyruvic acid
- B.
Hydrochloric acid
- C.
Sodium chloride
- D.
Both a & b
Correct Answer
A. Pyruvic acidExplanation
The end product of glycolysis is pyruvic acid. Glycolysis is the process of breaking down glucose into pyruvate molecules. During glycolysis, glucose is converted into two molecules of pyruvate through a series of enzymatic reactions. Pyruvic acid is an important intermediate in cellular respiration and can be further metabolized in the presence of oxygen to produce more ATP. Therefore, the correct answer is pyruvic acid.Rate this question:
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- 17.
What is the net ATP yield from one molecule of glucose during glycolysis?
- A.
4 ATP molecules
- B.
2 ATP molecules
- C.
6 ATP molecules
- D.
8 ATP molecules
Correct Answer
B. 2 ATP moleculesExplanation
Glycolysis is the breakdown of glucose into pyruvate, occurring in the cytoplasm. While four ATP molecules are produced, two ATP molecules are initially used during the energy-investment phase, resulting in a net gain of 2 ATP molecules.Rate this question:
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- 18.
The formation of Citrate at the start of Krebs' Cycle occurs through a _________________ reaction.
Correct Answer
synthesisExplanation
The formation of citrate at the start of Krebs' Cycle occurs through a synthesis reaction. In this reaction, acetyl CoA combines with oxaloacetate to form citrate. This process is catalyzed by the enzyme citrate synthase. The synthesis reaction is characterized by the formation of a new compound (citrate) from smaller molecules (acetyl CoA and oxaloacetate). This reaction is an essential step in the Krebs' Cycle as it initiates the series of reactions that ultimately lead to the production of ATP and other energy-rich molecules.Rate this question:
- 19.
Citrate ---> [ Aconitate ] ---> Isocitrate is an example of an ___________________ reaction.
Correct Answer
isomerizationExplanation
The given reaction, where citrate is converted to aconitate and then to isocitrate, involves the rearrangement of atoms within the molecule without any change in the overall composition. This type of reaction is known as isomerization. Isomerization reactions involve the conversion of one isomer to another, where isomers are molecules with the same molecular formula but different structural arrangements. In this case, citrate, a tricarboxylic acid, undergoes isomerization to form aconitate, which is a cis-aconitate isomer, and then isocitrate, which is a trans-aconitate isomer.Rate this question:
- 20.
When Isocitrate reacts to form ketoglutarate, one molecule of CO2 is lost. This is a ______________ reaction.
Correct Answer
oxidative decarboxylationExplanation
This is an oxidative decarboxylation reaction. In this type of reaction, a molecule (in this case, isocitrate) is oxidized and decarboxylated, meaning a carboxyl group is removed and released as carbon dioxide. The product of this reaction is alpha-ketoglutarate. This reaction is a key step in the citric acid cycle, also known as the Krebs cycle.Rate this question:
- 21.
Fumarate must react with H2O to form malate. This is a ____________________ reaction.
Correct Answer
hydrationExplanation
The given statement indicates that fumarate, a compound, needs to react with water (H2O) in order to form malate. This reaction is known as hydration, which involves the addition of water molecules to a compound.Rate this question:
- 22.
Fumarate must react with H2O to form malate. This is catalyzed by a ____________________ enzyme.
Correct Answer
fumarase, FumaraseExplanation
Fumarate reacts with H2O to form malate in a reaction that is catalyzed by the enzyme fumarase (also known as fumarate hydratase). This reaction is part of the citric acid cycle, which is crucial for cellular energy production in aerobic respiration. Fumarase specifically catalyzes the hydration of fumarate to malate, adding a water molecule across the double bond of the fumarate.Rate this question:
- 23.
The reaction: Malate + NAD+ ----> Oxaloacetate + NADH is an example of a ____________________ reaction
Correct Answer
redox, oxidation, reductionExplanation
The given reaction involves the transfer of electrons from malate to NAD+, resulting in the formation of NADH. This indicates a change in the oxidation state of the reactants, making it a redox reaction. Additionally, since malate loses electrons and NAD+ gains electrons, malate is being oxidized and NAD+ is being reduced. Therefore, the reaction can be classified as both oxidation and reduction.Rate this question:
- 24.
The reaction: Malate + NAD+ ----> Oxaloacetate + NADH is an example of a ____________________ reaction
- A.
Endergonic
- B.
Endothermic
- C.
Exothermic
- D.
None of these
Correct Answer
A. EndergonicExplanation
The reaction of Malate + NAD+ to Oxaloacetate + NADH is an example of an endergonic reaction. In an endergonic reaction, energy is absorbed from the surroundings to drive the reaction forward. In this case, the conversion of Malate to Oxaloacetate requires energy input, which is provided by the reduction of NAD+ to NADH. Therefore, this reaction is endergonic.Rate this question:
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- 25.
The FADH2 and NADH molecules in Krebs' Cycle serve as shuttles or carrier molecules for ______________.
Correct Answer
electronsExplanation
The FADH2 and NADH molecules in Krebs' Cycle serve as shuttles or carrier molecules for electrons. These molecules are involved in the transfer of electrons from the citric acid cycle to the electron transport chain, where they donate their electrons to the respiratory chain. This transfer of electrons is crucial for the production of ATP through oxidative phosphorylation, as it creates a flow of electrons that drives the synthesis of ATP molecules. Therefore, FADH2 and NADH play a vital role in the transportation of electrons, which is essential for energy production in the cell.Rate this question:
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Jan 13, 2025Quiz Edited by
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Mar 27, 2012Quiz Created by
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