Bch 211 - Exam 3
Study for final
Questions and Answers
- 1.
The chief use of acetyl coenzyme A is to provide fuel for
- A.
Glycolysis
- B.
The electron transport chain
- C.
The anaerobic sequence
- D.
The citric acid cycle
Correct Answer
D. The citric acid cycleExplanation
Acetyl coenzyme A is primarily used as a fuel source in the citric acid cycle, also known as the Krebs cycle or tricarboxylic acid cycle. This cycle is a key metabolic pathway that occurs in the mitochondria of cells and is responsible for generating energy in the form of ATP. Acetyl coenzyme A is produced from the breakdown of carbohydrates, fats, and proteins and enters the citric acid cycle to be further oxidized and generate energy-rich molecules such as NADH and FADH2. These molecules then participate in the electron transport chain to produce ATP. Therefore, the chief use of acetyl coenzyme A is to provide fuel for the citric acid cycle.Rate this question:
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- 2.
Most cellular ATP is produced within the
- A.
Nucleus
- B.
Mitochondria
- C.
Chloroplast
- D.
Cytoplasm
Correct Answer
B. MitochondriaExplanation
Most cellular ATP is produced within the mitochondria. Mitochondria are often referred to as the "powerhouses" of the cell because they are responsible for generating most of the cell's energy in the form of ATP through a process called cellular respiration. ATP is the main energy currency of the cell and is essential for various cellular processes. The mitochondria have their own DNA and are thought to have originated from ancient symbiotic bacteria that were engulfed by ancestral eukaryotic cells.Rate this question:
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- 3.
Which of the following vitamins serve as part of the coenzyme FAD?
- A.
Thiamine
- B.
Niacin
- C.
Riboflavin
- D.
Retinol
Correct Answer
C. RiboflavinExplanation
Riboflavin serves as part of the coenzyme FAD. Coenzymes are molecules that assist enzymes in carrying out their functions. FAD (flavin adenine dinucleotide) is a coenzyme that plays a crucial role in various metabolic reactions, particularly in energy production. Riboflavin, also known as vitamin B2, is converted into its active form, FAD, within the body. FAD is involved in processes such as the breakdown of carbohydrates, fats, and proteins to produce energy. Therefore, riboflavin is the correct answer as it serves as part of the coenzyme FAD.Rate this question:
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- 4.
An enzyme which catalyzes the conversion of -CH2-CH2 to -CH=CH- would most likely be accompanied by the coenzyme
- A.
A
- B.
NAD+
- C.
NADH
- D.
FAD
Correct Answer
D. FADExplanation
The conversion of -CH2-CH2 to -CH=CH- involves the removal of two hydrogen atoms. This type of reaction is typically carried out by enzymes called dehydrogenases, which require a coenzyme to accept the hydrogen atoms. FAD (Flavin adenine dinucleotide) is a common coenzyme for dehydrogenase enzymes. Therefore, an enzyme catalyzing this conversion is most likely accompanied by FAD.Rate this question:
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- 5.
During a metabolic pathway the following reaction produced 3.00 moles of product. If G for the hydrolysis of ATP is -7.3 kcal/mol, how much energy would be involved?
- A.
7.3 kcal released
- B.
7.3 kcal absorbed
- C.
22kcal absorbed
- D.
22 kcal released
Correct Answer
D. 22 kcal releasedExplanation
The hydrolysis of ATP is an exergonic reaction, meaning it releases energy. The given value of -7.3 kcal/mol for ΔG indicates that 7.3 kcal of energy is released per mole of ATP hydrolyzed. Since 3.00 moles of product are produced, the total energy released would be 7.3 kcal/mol * 3.00 moles = 22 kcal. Therefore, the correct answer is 22 kcal released.Rate this question:
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- 6.
Which of the following is a product of glycolysis?
- A.
Pyruvate
- B.
CO2 + H2O
- C.
Lactase
- D.
Acetyl CoA
Correct Answer
A. PyruvateExplanation
Pyruvate is a product of glycolysis, which is the metabolic pathway that converts glucose into pyruvate. During glycolysis, glucose is broken down into two molecules of pyruvate, along with the production of ATP and NADH. Pyruvate is then further metabolized in various ways depending on the presence or absence of oxygen, leading to the production of either lactate or acetyl CoA. Therefore, pyruvate is the correct answer as it is directly produced during glycolysis.Rate this question:
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- 7.
Glycolysis occurs within the
- A.
Mitochondria
- B.
Nucleus
- C.
Vacuoles
- D.
Cytoplasm
Correct Answer
D. CytoplasmExplanation
Glycolysis is the process of breaking down glucose into pyruvate molecules. It is the first step in cellular respiration and occurs in the cytoplasm of cells. The cytoplasm is the fluid-filled region outside the nucleus but within the cell membrane. This is where most of the cellular activities take place. Glycolysis does not occur in the mitochondria, nucleus, or vacuoles, as these organelles have different functions in the cell.Rate this question:
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- 8.
Under aerobic conditions in the body, pyruvate is converted to
- A.
Lactate
- B.
Acetyl CoA
- C.
Ethanol
- D.
Acetaldehyde
Correct Answer
B. Acetyl CoAExplanation
Under aerobic conditions in the body, pyruvate is converted to acetyl CoA. This process occurs in the mitochondria and is known as pyruvate decarboxylation. Pyruvate is first converted to acetyl CoA by the enzyme pyruvate dehydrogenase, which removes a carbon dioxide molecule. Acetyl CoA then enters the citric acid cycle, where it is further oxidized to produce energy in the form of ATP. This conversion of pyruvate to acetyl CoA is an important step in cellular respiration, allowing the body to efficiently extract energy from glucose.Rate this question:
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- 9.
Each turn of the citric acid cycle produces __________ molecules of CO2
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
B. 2Explanation
Each turn of the citric acid cycle produces two molecules of CO2. The citric acid cycle, also known as the Krebs cycle, is a series of chemical reactions that occur in the mitochondria of cells. During this cycle, a molecule of acetyl-CoA is oxidized, resulting in the production of three molecules of NADH, one molecule of FADH2, one molecule of ATP, and two molecules of CO2. Therefore, the correct answer is 2.Rate this question:
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- 10.
In the electron transport chain, FADH2 delivers hydrogen ions and electrons to
- A.
Coenzyme Q
- B.
NAD+
- C.
Flavoprotein (FP)
- D.
Cytochrome b
Correct Answer
A. Coenzyme QExplanation
FADH2 delivers hydrogen ions and electrons to coenzyme Q in the electron transport chain. Coenzyme Q acts as a carrier molecule, accepting electrons and hydrogen ions from FADH2 and transferring them to the next molecule in the chain, which is cytochrome b. This transfer of electrons and hydrogen ions is crucial for the production of ATP, the energy currency of the cell. NAD+ and flavoprotein (FP) are also involved in the electron transport chain, but they do not directly receive electrons and hydrogen ions from FADH2.Rate this question:
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- 11.
The final acceptor of electrons during electron transport is
- A.
NAD
- B.
NADH2
- C.
FAD
- D.
O2
Correct Answer
D. O2Explanation
In the process of electron transport, O2 serves as the final acceptor of electrons. It accepts the electrons and combines with hydrogen ions to form water. This occurs at the end of the electron transport chain, where the electrons have been passed down a series of protein complexes, generating energy in the form of ATP. O2 is essential for this process as it allows for the continuation of electron flow and the production of ATP.Rate this question:
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- 12.
The majority of ATP produced during the catabolism of glucose is formed during
- A.
Oxidative phosphorylation
- B.
Glycolysis
- C.
The citric acid cycle
- D.
The formation of acetyl CoA
Correct Answer
A. Oxidative phosphorylationExplanation
During the catabolism of glucose, the majority of ATP is produced during oxidative phosphorylation. This process occurs in the mitochondria and involves the transfer of electrons from NADH and FADH2 to the electron transport chain. As the electrons pass through the chain, they create a proton gradient across the inner mitochondrial membrane. This gradient is then used by ATP synthase to generate ATP from ADP and inorganic phosphate. Therefore, oxidative phosphorylation is the main process responsible for the production of ATP during glucose catabolism.Rate this question:
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- 13.
Glycogen is stored primarily in the liver and the
- A.
Heart
- B.
Pancreas
- C.
Muscles
- D.
Fat deposits
Correct Answer
C. MusclesExplanation
Glycogen is primarily stored in the muscles. It serves as a source of energy during physical activity, providing fuel for muscle contractions. This storage is essential for maintaining proper muscle function and endurance. The liver also stores glycogen, but its primary role is to regulate blood sugar levels by releasing glucose into the bloodstream when needed. While the heart and pancreas have important roles in the body, they do not store glycogen as significantly as the muscles and liver. Fat deposits, on the other hand, primarily store triglycerides, not glycogen.Rate this question:
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- 14.
Glycogenolysis can be correctly represented by which of the following
- A.
Glucose -> glycogen
- B.
Glycogen -> glucose
- C.
Pyruvate -> glycogen
- D.
Glycogen -> pyruvate
Correct Answer
B. Glycogen -> glucoseExplanation
Glycogenolysis refers to the breakdown of glycogen into glucose. This process occurs when the body needs glucose for energy. Therefore, the correct representation of glycogenolysis is "glycogen -> glucose", as it shows the conversion of glycogen into glucose.Rate this question:
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- 15.
The bulk of the energy utilized by marathon runners is provided by
- A.
Blood glucose
- B.
Glycogen
- C.
Protein
- D.
Fatty acids
Correct Answer
B. GlycogenExplanation
Marathon runners primarily rely on glycogen as their main source of energy. Glycogen is a stored form of glucose in the muscles and liver, which can be broken down and converted into glucose to fuel the body during prolonged exercise. This is because glycogen is readily available and can be quickly converted into glucose, providing a constant supply of energy for the muscles. While blood glucose also plays a role in providing energy, it is glycogen that is the primary source of fuel for marathon runners. Protein and fatty acids are not typically utilized as the main source of energy during endurance exercise.Rate this question:
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- 16.
Synthesis of glucose from pyruvate during the Cori cycle occurs primarily in the
- A.
Muscles
- B.
Liver
- C.
Bloodstream
- D.
Heart tissue
Correct Answer
B. LiverExplanation
The synthesis of glucose from pyruvate during the Cori cycle primarily occurs in the liver. The Cori cycle is a metabolic pathway that allows for the conversion of lactate produced by the muscles during intense exercise back into glucose. This glucose is then released into the bloodstream to be used by other tissues in the body. The liver plays a crucial role in this process as it has the necessary enzymes to convert lactate into glucose through gluconeogenesis. Therefore, the liver is responsible for maintaining blood glucose levels and providing energy to the body during prolonged exercise.Rate this question:
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- 17.
The main source of energy for the brain is
- A.
Glucose
- B.
Fatty acids
- C.
Glycogen
- D.
Glycerol
Correct Answer
A. GlucoseExplanation
Glucose is the main source of energy for the brain because it is easily transported across the blood-brain barrier and can be readily metabolized by brain cells. The brain relies heavily on glucose as its primary fuel source to support its high energy demands and maintain proper functioning. While fatty acids can also be used as an energy source by the brain, glucose is preferred due to its efficiency and accessibility. Glycogen and glycerol are not direct sources of energy for the brain, as they need to be converted into glucose first.Rate this question:
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- 18.
Which of the following hormones acts to lower the blood glucose level?
- A.
Glucagon
- B.
Insulin
- C.
Epinephrine
- D.
More than one response is correct
Correct Answer
B. InsulinExplanation
Insulin is a hormone that acts to lower the blood glucose level. It is produced by the pancreas and helps regulate glucose metabolism in the body. Insulin promotes the uptake of glucose by cells, especially in the liver, muscle, and adipose tissue, which reduces the concentration of glucose in the bloodstream. This hormone also stimulates the conversion of glucose into glycogen for storage in the liver and muscles. Overall, insulin plays a crucial role in maintaining blood glucose homeostasis by decreasing its levels.Rate this question:
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- 19.
Each turn of the citric acid cycle produces ___ NADH coenzyme(s).
- A.
0
- B.
1
- C.
2
- D.
3
Correct Answer
D. 3Explanation
In each turn of the citric acid cycle, three molecules of NADH coenzyme are produced. This is because during the cycle, three molecules of NAD+ are reduced to NADH. NADH is an important molecule in cellular respiration as it carries high-energy electrons to the electron transport chain, where ATP is produced. Therefore, the correct answer is 3.Rate this question:
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- 20.
The order of compounds in the conversion of glucose to pyruvic acid is as follows: (PEP = phosphoenolpyruvate)
- A.
Option 1
- B.
Option 2
- C.
Fructose-6-phosphate, fructose-bisphosphate, 1,3-phosphoglyceric acid, 3-phosphoglyceric acid, PEP
- D.
Option 4
Correct Answer
C. Fructose-6-phosphate, fructose-bisphosphate, 1,3-phosphoglyceric acid, 3-phosphoglyceric acid, PEPExplanation
The correct answer is the correct order of compounds in the conversion of glucose to pyruvic acid. The process starts with glucose being converted to fructose-6-phosphate, which is then converted to fructose-bisphosphate. Next, 1,3-phosphoglyceric acid is formed, followed by the conversion to 3-phosphoglyceric acid. Finally, phosphoenolpyruvate (PEP) is formed.Rate this question:
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- 21.
In the Cori cycle
- A.
Lactic acid is transported from the liver to muscle by the blood
- B.
Lactic acid is transported from the liver to the kidneys by the blood
- C.
Glycolysis takes place in muscle and gluconeogenesis in the liver
- D.
Glycolysis takes place in the liver and gluconeogenesis in muscle
Correct Answer
C. Glycolysis takes place in muscle and gluconeogenesis in the liverExplanation
The Cori cycle is a metabolic pathway that occurs in the liver and muscle cells. During intense exercise, muscles produce lactic acid as a byproduct of glycolysis. This lactic acid is then transported from the muscles to the liver through the bloodstream. In the liver, gluconeogenesis takes place, which is the process of converting lactic acid back into glucose. The glucose is then released into the bloodstream and transported back to the muscles, where it can be used as a source of energy. Therefore, the correct answer is that glycolysis takes place in muscle and gluconeogenesis occurs in the liver.Rate this question:
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- 22.
Glycolysis
- A.
Does not require O2 to generate energy
- B.
Requires O2 to generate energy
- C.
Is inhibited by O2
- D.
Rate is increased in presence of O2
Correct Answer
A. Does not require O2 to generate energyExplanation
Glycolysis is a metabolic pathway that occurs in the cytoplasm of cells and is the first step in the breakdown of glucose to generate energy. It is an anaerobic process, meaning it does not require oxygen to generate energy. Instead, glycolysis converts glucose into pyruvate, producing a small amount of ATP in the process. This makes glycolysis an important energy-producing pathway in cells, especially in situations where oxygen is limited or unavailable, such as during intense exercise or in anaerobic microorganisms.Rate this question:
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- 23.
Gluconeogenesis is the synthesis of
- A.
Glucose from non-carbohydrate precursors
- B.
Glycogen from glucose
- C.
Pyruvate from glucose
- D.
Fatty acids from glucose
Correct Answer
A. Glucose from non-carbohydrate precursorsExplanation
Gluconeogenesis is the process by which glucose is synthesized from non-carbohydrate precursors. This is an important metabolic pathway that occurs primarily in the liver and kidneys. During times of fasting or low carbohydrate intake, the body needs to maintain blood glucose levels for energy production. Gluconeogenesis allows the body to produce glucose from molecules such as amino acids, lactate, and glycerol, which are derived from non-carbohydrate sources. This process ensures a constant supply of glucose for the brain and other glucose-dependent tissues.Rate this question:
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- 24.
In the diagram of the citric acid cycle shown, What do the two points indicated by an asterisk have in common.
- A.
Draw structure of CitrateÂ
![Bch 211 - Exam 3 - Quiz]()
- B.
Draw structure of Succinate
![Bch 211 - Exam 3 - Quiz]()
- C.
How man carbons does Malate have? (ans: 4)
- D.
 (ans:  TRUE)
![Bch 211 - Exam 3 - Quiz]()
- E.
 (ans:  FALSE)
![Bch 211 - Exam 3 - Quiz]()
Correct Answer
B. Draw structure of Succinate -
- 25.
In the diagram what are the names of the metabolic pathways indicated by the numers?
- A.
1-glycogenolysis 2-glycogenesis 3-gluconeogenesis 4-glycolysis
- B.
1-glycogenesis 2-glycogenolysis 3-glycolysis 4-gluconeogenesis
- C.
1-glycolysis 2-glycogenesis 3-gluconeogenesis 4-glycogenolysis
- D.
1-glycogenolysis 2-glycogenesis 3-glucolysis 4-gluconeogenesis
Correct Answer
A. 1-glycogenolysis 2-glycogenesis 3-gluconeogenesis 4-glycolysisExplanation
The correct answer is 1-glycogenolysis, 2-glycogenesis, 3-gluconeogenesis, and 4-glycolysis. Glycogenolysis is the breakdown of glycogen into glucose, glycogenesis is the synthesis of glycogen from glucose, gluconeogenesis is the production of glucose from non-carbohydrate sources, and glycolysis is the breakdown of glucose into pyruvate.Rate this question:
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- 26.
In humans, pyruvate can be converted to
- A.
Acetyl-CoA only
- B.
Lactate only
- C.
Ethanol only
- D.
Acetyl-CoA or lactate
Correct Answer
D. Acetyl-CoA or lactateExplanation
Pyruvate, a product of glycolysis, can be converted to acetyl-CoA or lactate in humans. The conversion to acetyl-CoA occurs in the mitochondria and is a crucial step in aerobic respiration, where it enters the citric acid cycle to produce ATP. However, under anaerobic conditions or during intense exercise, pyruvate can be converted to lactate in the cytoplasm as a means of regenerating NAD+ for glycolysis to continue. Therefore, the correct answer is that pyruvate can be converted to acetyl-CoA or lactate in humans.Rate this question:
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- 27.
What is the net ATP yield per glucose during glycolysis?
- A.
1
- B.
2
- C.
3
- D.
4
- E.
6
Correct Answer
B. 2Explanation
During glycolysis, which is the first step of cellular respiration, one molecule of glucose is converted into two molecules of pyruvate. This process generates a net of two molecules of ATP. Therefore, the net ATP yield per glucose during glycolysis is 2.Rate this question:
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- 28.
What is the role of ATP synthase?
- A.
Make ADP in the Fo unit
- B.
Make ATP from ADP and Pi
- C.
Move protons into IMM space
- D.
Rotate and stir cell contents
Correct Answer
B. Make ATP from ADP and PiExplanation
ATP synthase is responsible for making ATP from ADP and Pi (inorganic phosphate). This enzyme is located in the inner mitochondrial membrane and is involved in the process of oxidative phosphorylation. As protons flow through the enzyme, it causes a rotation of the ATP synthase complex, which then catalyzes the synthesis of ATP from ADP and Pi. This process is crucial for the production of ATP, the main energy currency of the cell.Rate this question:
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- 29.
The phosphorylation of glucose to glucose 6-phosphate
- A.
Is so strongly exergonic that it does not require a catalyst
- B.
Is an exergonic reaction not coupled to any other reaction
- C.
Is an endergonic reaction that takes place because it is coupled to the exergonic hydrolysis of ATP
- D.
Is an exergonic reaction that is coupled to the endergonic hydrolysis of ATP
Correct Answer
C. Is an endergonic reaction that takes place because it is coupled to the exergonic hydrolysis of ATPExplanation
The phosphorylation of glucose to glucose 6-phosphate is an endergonic reaction that takes place because it is coupled to the exergonic hydrolysis of ATP. In this reaction, the transfer of a phosphate group from ATP to glucose requires energy input, making it endergonic. However, this reaction is made favorable by coupling it with the exergonic hydrolysis of ATP, which releases a large amount of energy. The energy released from ATP hydrolysis is used to drive the endergonic phosphorylation of glucose.Rate this question:
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- 30.
The binding of glucose to hexokinase
- A.
Is an example of lock-and-key binding of a substrate to the active site of an enzyme
- B.
Is an example of induced-fit binding of a substrate to the active site of an enzyme
- C.
Differs from the binding of substrates to other kinases
- D.
Is not well characterized
Correct Answer
B. Is an example of induced-fit binding of a substrate to the active site of an enzymeExplanation
The binding of glucose to hexokinase is an example of induced-fit binding of a substrate to the active site of an enzyme. This means that the active site of the enzyme undergoes a conformational change upon binding with the substrate. In this case, the active site of hexokinase undergoes a shape change to accommodate the glucose molecule and form a stable enzyme-substrate complex. This induced-fit binding allows for a more precise and efficient catalysis of the reaction. It differs from lock-and-key binding, where the active site has a rigid shape that perfectly matches the substrate. The binding of glucose to hexokinase has been well characterized.Rate this question:
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- 31.
Which of the following is FALSE about glycolysis?
- A.
Every reaction is a metabolic pathway must have a negative , or the pathway cannot run
![Bch 211 - Exam 3 - Quiz]()
- B.
The reaction with the largest negative is the hexokinase reaction
![Bch 211 - Exam 3 - Quiz]()
- C.
The overall pathway of glycolysis has a negative
![Bch 211 - Exam 3 - Quiz]()
- D.
One molecule of glucose ends in two molecules of pyruvate
Correct Answer
A. Every reaction is a metabolic pathway must have a negative , or the pathway cannot run -
- 32.
Which group of small molecules best fits the boxes associated with the reaction shown?
- A.
ATP ADP H2O
- B.
NADH NAD+ Pi
- C.
NAD+ NADH H2O
- D.
NAD+ NADH Pi
Correct Answer
D. NAD+ NADH PiExplanation
The reaction shown involves the conversion of NAD+ to NADH and the addition of a phosphate group (Pi). This is consistent with the answer choice NAD+ NADH Pi, as it correctly represents the molecules involved in the reaction.Rate this question:
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- 33.
Consider the following information: deltaG = -61.9 kJ/mol deltaG = +30.5 kJ/mol How many molecules of ATP might theoreticallly have been produced when coupled to tht conversion of one molecule phosphoenolpyruvate to pyruvate?
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
B. 2Explanation
Based on the given information, the change in Gibbs free energy (deltaG) is negative, indicating that the reaction is exergonic and releases energy. The production of ATP is coupled to the conversion of phosphoenolpyruvate to pyruvate, which is an exergonic reaction. Each molecule of ATP is produced by the transfer of a phosphate group from a high-energy compound to ADP. Since the reaction is exergonic, it can potentially produce enough energy to form two molecules of ATP. Therefore, the correct answer is 2.Rate this question:
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- 34.
The citric acid cycle is amphibolic, meaning
- A.
It plays a role in both anabolism and catabolism
- B.
It is essentially irreversible
- C.
It can operate both in the presence and absence of oxygen
- D.
It can oxidize carbons and nitrogens equally well
Correct Answer
A. It plays a role in both anabolism and catabolismExplanation
The citric acid cycle is amphibolic because it is involved in both anabolism and catabolism. In anabolism, the cycle provides precursors for the synthesis of molecules such as amino acids, nucleotides, and lipids. In catabolism, the cycle breaks down acetyl-CoA, derived from carbohydrates, fats, and proteins, to produce energy in the form of ATP. This dual role allows the citric acid cycle to contribute to both the breakdown and synthesis of molecules, making it an important metabolic pathway in cells.Rate this question:
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- 35.
When mitochondria are actively carrying out aerobic respiration
- A.
The pH of the matrix is greater than the pH of the intermembrane space
- B.
The pH of the matrix is less than the pH of the intermembrane space
- C.
The pH of the matrix is about the same as the pH of the intermembrane space
- D.
The pH of the matrix versus the intermembrane space has nothing to do with whether not aerobic respiration is occurring
Correct Answer
A. The pH of the matrix is greater than the pH of the intermembrane spaceExplanation
During active aerobic respiration, the mitochondria produce ATP by utilizing oxygen. This process involves the electron transport chain, which pumps protons (H+) from the matrix to the intermembrane space. As a result, the concentration of protons is higher in the intermembrane space compared to the matrix, leading to a lower pH in the intermembrane space. Therefore, the pH of the matrix is greater than the pH of the intermembrane space.Rate this question:
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- 36.
The ultimate electron acceptor in the electron transport chain is
- A.
NAD+
- B.
FAD
- C.
Oxygen
- D.
ADP
Correct Answer
C. OxygenExplanation
In the electron transport chain, electrons are passed along a series of protein complexes, creating a flow of energy. Oxygen serves as the ultimate electron acceptor, as it combines with electrons and protons to form water. This process is crucial for the production of ATP, the main energy currency of cells. NAD+ and FAD are electron carriers that shuttle electrons to the electron transport chain, while ADP is converted to ATP during the process. However, oxygen is the final electron acceptor, allowing the electron transport chain to continue functioning.Rate this question:
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- 37.
Complex III of the electron transport chain oxidizes _____ , reduces _____ ,and ____ protons in the process
- A.
Coenzyme Q; cytochrome c; pumps
- B.
Coenzyme Q; cytochrome c; doesn't pump
- C.
Cytochrome c; coenzyme Q; pumps
- D.
Cytochrome c; coenzyme Q; doesn't pump
Correct Answer
A. Coenzyme Q; cytochrome c; pumpsExplanation
Complex III of the electron transport chain oxidizes coenzyme Q, reduces cytochrome c, and pumps protons in the process.Rate this question:
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- 38.
Complex I of the electron transport chain oxidizes _____ , reduces _____ , and _____ protons in the process
- A.
FADH2; coenzyme Q; doesn't pump
- B.
FADH2; coenzyme Q; pumps
- C.
NADH; coenzyme Q; doesn't pump
- D.
NADH; coenzyme Q; pumps
Correct Answer
D. NADH; coenzyme Q; pumps -
- 39.
The final reduced species in the electron transport chain is
- A.
O2
- B.
H2O
- C.
Cytochrome c
- D.
Coenzyme Q
Correct Answer
B. H2OExplanation
In the electron transport chain, electrons are passed along a series of protein complexes and coenzymes. These electrons ultimately combine with molecular oxygen (O2) and hydrogen ions (H+) to form water (H2O) as the final reduced species. This process occurs in the last step of the electron transport chain, where oxygen acts as the final electron acceptor. Therefore, the correct answer is H2O.Rate this question:
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- 40.
Which complex of the electron transport chain does NOT contain an iron-sulfur cluster?
- A.
Complex 1
- B.
Complex 2
- C.
Complex 3
- D.
Complex 4
Correct Answer
D. Complex 4Explanation
Complex 4, also known as cytochrome c oxidase, is the final complex in the electron transport chain. It is responsible for transferring electrons from cytochrome c to oxygen, resulting in the production of water. Unlike the other complexes in the electron transport chain, complex 4 does not contain an iron-sulfur cluster. Instead, it contains copper ions that help facilitate the transfer of electrons to oxygen.Rate this question:
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- 41.
Which complex contains succinate dehydrogenase?
- A.
Complex 1
- B.
Complex 2
- C.
Complex 3
- D.
Complex 4
Correct Answer
B. Complex 2Explanation
Succinate dehydrogenase is a key enzyme in the citric acid cycle and is involved in the electron transport chain. It is located in the inner mitochondrial membrane and is part of complex 2, also known as succinate-ubiquinone oxidoreductase. This complex plays a crucial role in transferring electrons from succinate to ubiquinone, generating FADH2 in the process. Therefore, complex 2 is the correct complex that contains succinate dehydrogenase.Rate this question:
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- 42.
Which complex contains cytochrome oxidase?
- A.
Complex 1
- B.
Complex 2
- C.
Complex 3
- D.
Complex 4
Correct Answer
D. Complex 4Explanation
Complex 4, also known as cytochrome c oxidase, is the complex that contains cytochrome oxidase. Cytochrome c oxidase is an enzyme that plays a crucial role in the electron transport chain, where it transfers electrons to oxygen, resulting in the formation of water. This complex is responsible for the final step in aerobic respiration, making it an essential component in the production of ATP.Rate this question:
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- 43.
The only complex which actually uses molecular oxygen is
- A.
Complex 1
- B.
Complex 2
- C.
Complex 3
- D.
Complex 4
Correct Answer
D. Complex 4Explanation
Complex 4 is the only complex that actually uses molecular oxygen. This is because complex 4, also known as cytochrome c oxidase, is responsible for the final step in the electron transport chain, where it transfers electrons to oxygen to form water. Complex 1, complex 2, and complex 3 are involved in electron transfer processes but do not directly use molecular oxygen.Rate this question:
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- 44.
Oxidative phosphorylation is coupled to electron transport in
- A.
Complexes 1, 2, 3
- B.
Complex 1, 2, 4
- C.
Complex 1, 3, 4
- D.
All four respiratory complexes
Correct Answer
C. Complex 1, 3, 4Explanation
Oxidative phosphorylation is the process in which ATP is synthesized using energy from electron transport. Complexes 1, 3, and 4 are involved in the electron transport chain, which is a series of protein complexes that transfer electrons and generate a proton gradient. This proton gradient is then used by ATP synthase (complex 5) to produce ATP. Therefore, oxidative phosphorylation is coupled to electron transport in complexes 1, 3, and 4.Rate this question:
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Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.
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Current Version
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Mar 21, 2023Quiz Edited by
ProProfs Editorial Team -
Dec 16, 2013Quiz Created by
Grj2010