Chapter 7 Test File Questions
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1. ATP is
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A. a short-term energy-storage compound.
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B. the cell’s principal compound for energy transfers.
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C. synthesized within mitochondria.
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D. the molecule all living cells rely on to do work.
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E. All of the above
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This Chapter 7 Test File Questions assesses knowledge on metabolic pathways, redox reactions, and enzyme regulation. It evaluates understanding of core concepts such as ATP functions, anabolic and catabolic pathways, and roles of NAD+ in cellular processes.
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2. Which of the following statements about metabolic pathways is false?
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A. The product of one reaction becomes the reactant for the next reaction.
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B. They are a series of enzyme-catalyzed reactions.
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C. Almost all are anabolic.
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D. They are similar in all organisms.
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E. Many are compartmentalized in eukaryotes.
Correct Answer
A. C. Almost all are anabolic.Explanation
Metabolic pathways are a series of enzyme-catalyzed reactions where the product of one reaction becomes the reactant for the next reaction. This statement is supported by option a. Option b also accurately describes metabolic pathways. However, option c is false because not all metabolic pathways are anabolic. Some pathways are catabolic, breaking down molecules to release energy. Option d is also false because metabolic pathways can vary between organisms. Option e is true, as many metabolic pathways are compartmentalized in eukaryotes.Rate this question:
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- 3.
3. Which of the following statements about metabolic pathways is true?
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A. Complex chemical transformations in the cell occur in a single reaction.
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B. Each reaction requires oxygen.
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C. In eukaryotes they occur in the cytoplasm.
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D. They vary from organism to organism.
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E. Each one is regulated by specific enzymes.
Correct Answer
A. E. Each one is regulated by specific enzymes.Explanation
Metabolic pathways involve a series of chemical reactions that convert molecules into different forms, allowing cells to carry out essential functions. The statement that each metabolic pathway is regulated by specific enzymes is true. Enzymes act as catalysts, facilitating and regulating the reactions in metabolic pathways. They control the rate at which reactions occur and ensure that the pathway functions efficiently. Without specific enzymes, metabolic pathways would not be able to proceed effectively, leading to disruptions in cellular processes. Therefore, the correct answer is e. Each one is regulated by specific enzymes.Rate this question:
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- 4.
4. When a molecule loses hydrogen atoms (as opposed to hydrogen ions), it becomes
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A. reduced.
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B. oxidized.
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C. redoxed.
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D. hydrogenated.
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E. hydrolyzed.
Correct Answer
A. B. oxidized.Explanation
When a molecule loses hydrogen atoms, it means that it is losing electrons along with the hydrogen atoms. This process is known as oxidation. Therefore, the correct answer is b. oxidized.Rate this question:
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- 5.
5. In the conversion of succinate to fumarate, hydrogen atoms are transferred to FAD. The conversion of succinate and FAD to fumarate and FADH2 is an example of
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A. hydrolysis.
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B. an allosteric reaction.
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C. a metabolic pathway.
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D. an aerobic reaction.
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E. a redox reaction.
Correct Answer
A. E. a redox reaction.Explanation
The conversion of succinate to fumarate involves the transfer of hydrogen atoms to FAD, which is a form of electron transfer. This transfer of electrons is characteristic of a redox reaction, where there is a simultaneous oxidation and reduction of molecules involved. In this case, succinate is oxidized (loses electrons) while FAD is reduced (gains electrons), resulting in the formation of fumarate and FADH2. Therefore, the correct answer is e. a redox reaction.Rate this question:
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- 6.
6. The oxidation of malate to oxaloacetate is coupled to the reduction of NAD+ to NADH + H+. NAD+ is a(n)
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A. reducing agent.
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B. oxidizing agent.
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C. vitamin.
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D. phosphate ester.
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E. phosphorylating agent.
Correct Answer
A. B. oxidizing agent.Explanation
NAD+ acts as an oxidizing agent in the given reaction because it accepts electrons and becomes reduced to NADH + H+. In other words, NAD+ gains electrons and is responsible for oxidizing malate to oxaloacetate.Rate this question:
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- 7.
7. Which of the following processes occurs when oxygen is unavailable?
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A. Pyruvate oxidation
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B. The citric acid cycle
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C. Fermentation
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D. An electron transport chain
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E. All of the above
Correct Answer
A. C. FermentationExplanation
Fermentation occurs when oxygen is unavailable because it is an anaerobic process that allows for the production of ATP without the use of oxygen. During fermentation, glucose is broken down into smaller molecules, such as lactic acid or ethanol, in order to generate energy. This process is commonly observed in microorganisms and certain types of cells in the human body, such as muscle cells during intense exercise.Rate this question:
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- 8.
8. In all cells, glucose metabolism begins with
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A. glycolysis.
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B. fermentation.
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C. pyruvate oxidation.
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D. the citric acid cycle.
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E. chemiosmosis.
Correct Answer
A. A. glycolysis.Explanation
Glucose metabolism begins with glycolysis, which is the process of breaking down glucose into pyruvate. This is the first step in cellular respiration and occurs in the cytoplasm of the cell. Glycolysis does not require oxygen and can occur in both aerobic and anaerobic conditions. It produces a small amount of ATP and NADH, which can then be used in further steps of cellular respiration to produce more ATP.Rate this question:
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- 9.
9. When NADH donates two electrons to ubiquinone during respiration, ubiquinone is
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A. reduced.
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B. oxidized.
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C. phosphorylated.
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D. aerobic.
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E. hydrolyzed.
Correct Answer
A. A. reduced.Explanation
When NADH donates two electrons to ubiquinone during respiration, ubiquinone gains the electrons and becomes reduced. Reduction is the process of gaining electrons or gaining hydrogen atoms. Therefore, the correct answer is a. reduced.Rate this question:
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- 10.
10. The end product of glycolysis is
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A. pyruvate.
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B. the starting point for pyruvate oxidation.
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C. the starting point for the fermentation pathway.
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D. Both a and b
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E. All of the above
Correct Answer
A. E. All of the aboveExplanation
The end product of glycolysis is pyruvate, which can be further oxidized in the process of pyruvate oxidation. Pyruvate can also serve as the starting point for the fermentation pathway, where it can be converted into various end products depending on the specific type of fermentation. Therefore, all of the options (a, b, and c) are correct.Rate this question:
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- 11.
11. Which of the following oxidizes other compounds by gaining free energy and hydrogen atoms and reduces other compounds by giving up free energy and hydrogen atoms?
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A. Vitamins
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B. Adenine
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C. ATP
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D. NAD
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E. Riboflavin
Correct Answer
A. D. NADExplanation
NAD (nicotinamide adenine dinucleotide) is a coenzyme that plays a crucial role in cellular metabolism. It functions as an electron carrier, accepting electrons and hydrogen atoms from other compounds during oxidation reactions. This process allows NAD to gain free energy and become reduced. On the other hand, NAD can also donate these electrons and hydrogen atoms to other compounds during reduction reactions, thereby giving up free energy. Therefore, NAD is capable of both oxidizing and reducing other compounds, making it the correct answer to the question.Rate this question:
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- 12.
12. The function of NAD+ is to
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A. cause the release of energy to adjacent cells when energy is needed in aerobic conditions.
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B. hasten the release of energy when the cell has been deprived of oxygen.
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C. carry hydrogen atoms and free energy from compounds being oxidized and to give hydrogen atoms and free energy to compounds being reduced.
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D. block the release of energy to adjacent cells.
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E. None of the above
Correct Answer
A. C. carry hydrogen atoms and free energy from compounds being oxidized and to give hydrogen atoms and free energy to compounds being reduced.Explanation
The function of NAD+ is to carry hydrogen atoms and free energy from compounds being oxidized and to give hydrogen atoms and free energy to compounds being reduced. This is an important role in cellular respiration, as NAD+ acts as an electron carrier in redox reactions. It accepts electrons and hydrogen ions from molecules that are being oxidized, and then transfers them to molecules that are being reduced. This process helps in the production of ATP, the energy currency of the cell.Rate this question:
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13. NAD
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A. is a key electron carrier in redox reactions.
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B. requires oxygen to function.
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C. is found only in prokaryotes.
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D. binds with an acetyl group to form acetyl CoA.
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E. detoxifies hydrogen peroxide.
Correct Answer
A. A. is a key electron carrier in redox reactions.Explanation
NAD (nicotinamide adenine dinucleotide) is a coenzyme that plays a crucial role as an electron carrier in redox reactions. It acts as a shuttle, accepting electrons from one molecule and transferring them to another, facilitating the conversion of energy in the process. NAD is involved in various metabolic processes, including cellular respiration and fermentation. It is present in both prokaryotes and eukaryotes, making option c incorrect. Options b, d, and e are also incorrect as they do not accurately describe the role of NAD.Rate this question:
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- 14.
14. In the cell, the site of oxygen utilization is the
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A. nucleus.
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B. chloroplast.
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C. endoplasmic reticulum.
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D. mitochondrion.
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E. cytosol.
Correct Answer
A. D. mitochondrion.Explanation
The mitochondrion is the site of oxygen utilization in the cell. It is responsible for producing energy in the form of ATP through a process called cellular respiration. Oxygen is used in the electron transport chain within the mitochondria to generate ATP. The other options, such as the nucleus, chloroplast, endoplasmic reticulum, and cytosol, do not play a direct role in oxygen utilization.Rate this question:
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- 15.
15. In the first reaction of glycolysis, glucose receives a phosphate group from ATP. This reaction is
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A. respiration.
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B. a redox reaction.
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C. exergonic.
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D. endergonic.
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E. fermentation.
Correct Answer
A. D. endergonic.Explanation
In the first reaction of glycolysis, glucose receives a phosphate group from ATP. This means that energy is being consumed or absorbed in the process, making it endergonic. Endergonic reactions require an input of energy to proceed.Rate this question:
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- 16.
16. During the energy-priming portion of glycolysis, the phosphates from ATP molecules are
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A. added to the first and sixth carbons.
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B. added to the second and fourth carbons.
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C. wasted, as an energy investment.
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D. used to make pyruvate.
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E. used to make lactate.
Correct Answer
A. A. added to the first and sixth carbons.Explanation
During the energy-priming portion of glycolysis, the phosphates from ATP molecules are added to the first and sixth carbons. This step involves the phosphorylation of glucose, which is the first step in glycolysis. The addition of the phosphate groups to the first and sixth carbons of glucose helps to destabilize the molecule and make it more reactive. This allows for further breakdown of glucose and the production of ATP and other energy-rich molecules.Rate this question:
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Mar 20, 2023Quiz Edited by
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Mar 17, 2010Quiz Created by
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