Chapter 9 Flashcards
NAD+ is
A. a type of organelle.
B. a protein.
C. present only in mitochondria.
D. a part of ATP.
E. formed in the reaction that produces ethanol.
E
Compared with fermentation, the aerobic pathways of glucose metabolism produce
A. more ATP.
B. pyruvate.
C. fewer protons for pumping in the mitochondria.
D. less CO2.
E. more oxidized coenzymes.
A
Glycolysis
A. takes place in the mitochondrion.
B. produces no ATP.
C. has no connection with the respiratory chain.
D. is the same thing as fermentation.
E. reduces two molecules of NAD+ for every glucose molecule processed.
E
Which statement about pyruvate is not true?
A. It is the end product of glycolysis.
B. It becomes reduced during fermentation.
C. It is a precursor of acetyl CoA.
D. It is a protein.
E. It contains three carbon atoms.
D
The citric acid cycle
A. has no connection with the respiratory chain.
B. is the same thing as fermentation.
C. reduces two NAD+ for every glucose processed.
D. produces no ATP.
E. takes place in the mitochondrion.
E
Which statement about oxidative phosphorylation is not true?
A. It forms ATP by the respiratory chain/ATP synthesis.
B. It is brought about by chemiosmosis.
C. It requires aerobic conditions.
D. It takes place in mitochondria.
E. Its functions can be served equally well by fermentation.
E
The respiratory chain
A. is located in the mitochondrial matrix.
B. includes only peripheral membrane proteins.
C. always produces ATP.
D. reoxidizes reduced coenzymes.
E. operates simultaneously with fermentation.
D
Oxidation and reduction
A. entail the gain or loss of proteins.
B. are defined as the loss of electrons.
C. are both endergonic reactions.
D. always occur together.
E. proceed only under aerobic conditions.
D
Fermentation
A. takes place in the mitochondrion.
B. takes place in all animal cells.
C. does not require O2.
D. requires lactic acid.
E. prevents glycolysis.
C
The role of oxygen gas in our cells is to
A. catalyze reactions in glycolysis.
B. produce CO2.
C. form ATP.
D. accept electrons from the respiratory chain.
E. react with glucose to split water.
D
When NADH donates two electron to ubiquinone during respiration, ubiquinone is
A. reduced.
B. oxidized.
C. phosphorylated.
D. aerobic.
E. hydrolyzed.
A
Many species derive their energy from fermentation. The function of fermentation is to
A. reduce NAD+
B. oxidize CO2.
C. oxidize NADH + H+, ensuring a continued supply of ATP.
D. produce acetyl CoA.
E. None of the above
C
Water is a by-product of cellular repiration. The water is produced as a result of the
A. combining of CO2 with protons.
B. conversion of pyruvate to acetyl CoA.
C. degradation of glucose to pyruvate.
D. reduction of oxygen at the end of the electron transport chain.
E. None of the above
D
Which of the following processes occurs when oxygen is unavailable?
A. Pyruvate oxidation
B. The citric acid cycle
C. Fermentation
D. An electron transport chain
E. All of the above
C
When a molecule loses hydrogen atoms (as opposed to hydrogen ions), it becomes
A. reduced.
B. oxidized.
C. redoxed.
D. hydrogenated.
E. hydrolyzed.
B
The end result of glycolysis is the
A. creation of 38 molecules of ATP.
B. reduction of 8 molecules of NAD.
C. formation of 2 molecules of pyruvate.
D. conversion of 1 molecule of glucose to lactic acid.
E. None of the above
C
Animals breathe in air containing oxygen and breathe out air with less oxygen and more carbon dioxide. The carbon dioxide comes from
A. hydrocarbons and the air.
B. the citric acid cycle.
C. glycolysis.
D. waste products.
E. All of the above
B
In yeast, if the citric acid cycle is shut down because of a lack of oxygen, glycolysis will probably
A. shut down.
B. increase.
C. produce more ATP per mole of glucose.
D. produce more NADH per mole of glucose.
E. produce acetyl CoA for fatty acid synthesis.
B
Before starch can be used for repiratiory ATP production, it mush be hydrolyzed to
A. pyruvate.
B. fatty acids.
C. amino acids.
D. glucose.
E. oxaloacetate.
D
The proton-motive force is
A. ATP synthase.
B. the proton concentration gradient and electric charge difference.
C. a metabolic pathway.
D. a redox reaction.
E. None of the above
B
In steps 6-10 of glycolysis, the conversion of 1 mole of glyceraldehyde 3-phosphate to pyruvate yields 2 moles of ATP. But the oxidation of glucose to pyruvate produces a total of 4 moles of ATP. Where do the remaining 2 moles of ATP come from?
A. One mole of glucose yields 2 moles of glyceraldehyde 3-phosphate.
B. Two moles of ATP are used during the conversion of glucose to glyceraldehyde 3-phosphate.
C. Glycolysis produces 2 moles of NADH.
D. Fermentation of pyruvate to lactic acid yields 2 moles of ATP.
E. Fermentation of pyruvate to lactic acid yields 2 moles of NAD+.
A
Most ATP produced in our bodies is made
A. by glycolysis.
B. in the citric acid cycle.
C. using ATP synthase.
D. from photosynthesis.
E. by burning fat.
C
Which of the following statements regarding cellular energy-harvesting pathways is false?
A. The net amount of ATP made during cellular respiration is greater than that made during fermentation.
B. The products of glycolysis can be used in either cellular respiration or fermentation.
C. Both cellular respiration and fermentation require O2 as an electron acceptor.
D. Both cellular respiration and fermentation involve several biochemical reactions.
E. Plant-eating animals can obtain energy from the products of photosynthesis.
C
Which of the following statements regarding the oxidation–reduction reaction shown here is true?
A. Reactant A is the oxidizing agent.
B. Reactant B is oxidized.
C. Reactant B is the reducing agent.
D. Both oxidation and reduction occur together.
E. In the reverse reaction, reactant B is the oxidizing agent.
D
Which of the following statements regarding the coupled reactions shown in the figure is false?
A. AH is oxidized.
B. NAD+ acts as a reducing agent.
C. The oxidation of NADH by O2 is exergonic.
D. NADH is a reducing agent.
E. B acts as an oxidizing agent.
B
Which of the following statements regarding NAD+ and NADH (see figure) is false?
A. NAD+ is the oxidized form of the molecule.
B. Free energy is released during the oxidation of NADH by O2.
C. The reduced form of this molecule is NADH.
D. NAD+ and FAD transfer electrons during the compete oxidation of glucose.
E. NAD+ is found only in the cytoplasm.
E
Which of the following statements regarding energy balance in glycolysis is false?
A. Two of the first five steps of glycolysis require ATP.
B. Glycolysis would continue even after all of the NAD+ is reduced.
C. Energy is harvested in the form of NADH and ATP in three of the last five steps of glycolysis.
D. The ATP generated during glycolysis occurs by substrate-level phosphorylation.
E. The energy lost from the glucose molecule as it is metabolized to pyruvate is conserved by coupling glucose catabolism to the formation of ATP and NADH.
B
Which of the following events does not take place during pyruvate oxidation?
A. Pyruvate is oxidized to form acetyl CoA.
B. Acetyl CoA formation occurs in the mitochondrial matrix.
C. Cytoplasmic NAD+ is reduced in eukaryotes.
D. One molecule of CO2 is produced for each pyruvate oxidized.
E. Coenzyme A is used to bind to the 2-carbon acetyl moiety.
C
Which of the following statements regarding the citric acid cycle depicted here is false?
A. The major inputs to the cycle are acetyl CoA, NAD+ and FAD, ADP, and Pi.
B. The outputs of the cycle are CO2, ATP, NADH, FADH2, and Coenzyme A.
C. The formation of citric acid from acetyl CoA is the initial step in the cycle.
D. Energy released during the cycle is captured in ATP, NADH, and FADH2.
E. There is no substrate-level ATP synthesis in the citric acid cycle as there is in glycolysis.
E
Which of the following statements regarding the process of lactic acid fermentation (see figure) is false?
A. Lactic acid is formed through the oxidation of pyruvate during lactic acid fermentation.
B. Lactic acid fermentation can occur in microorganisms.
C. Lactic acid fermentation can occur in certain tissues of animal bodies.
D. NAD+ is regenerated during lactic acid fermentation for use in glycolysis.
E. Lactic acid fermentation produces as much ATP per molecule of glucose as alcoholic fermentation.
A
Which of the following statements regarding the electron transport chain (see figure) is false?
A. Electrons are passed through a series of membrane-associated electron carriers.
B. The flow of electrons drives the active transport of H+ ions from the mitochondrial matrix to the intermembrane space.
C. Electron transport by the mitochondrial electron transport chain occurs in the absence of O2.
D. The sources of electrons for the electron transport chain are NADH and FADH2.
E. The proton gradient formed from the electron transport chain is used to drive the formation of ATP.
C
Which statement about ATP synthesis in mitochondria is false?
A. Increasing the permeability of the inner mitochondrial membrane to protons (H+) would inhibit ATP synthesis.
B. Blocking electron transport would not affect ATP synthesis.
C. The proton-motive force includes an electrical component.
D. ATP synthase makes most of the ATP in mitochondria.
E. There is substrate level ATP synthesis in mitochondria.
B
The growth rate of a yeast using glucose as an energy and carbon source would likely _______ when the culture was shifted from aerobic to anaerobic conditions; the rate of utilization of glucose would _______ after the transition.
A. increase; decrease
B. decrease; decrease
C. stay the same; increase
D. increase; stay the same
E. decrease; increase
E
ATP yields under anaerobic conditions are considerably lower than those of oxidative phosphorylation. The growth of the yeast could be limited by the rate of ATP synthesis. To partially compensate for the low yield of ATP during fermentation, yeast increases its rate of glucose catabolism.
Which statement concerning the pathways or reactions that are shared during the aerobic catabolism of fats and glucose is true?
A. Glucose and fat breakdown share only pyruvate oxidation.
B. Glucose and fat breakdown share only acetyl CoA production.
C. Glucose and fat breakdown share only glycolysis.
D. Glucose and fat breakdown share glycolysis, acetyl CoA production, and pyruvate oxidation.
E. Glucose and fat breakdown share the citric acid cycle.
E
It is true that both pathways use the citric acid cycle, but both also use glycolysis, pyruvate oxidation, and acetyl CoA production.
The accompanying figure shows allosteric regulation of glycolysis and the citric acid cycle. Which of the following events would not be expected to occur when a cell begins to produce more NADH than the respiratory chain can use?
A. Activation of isocitrate dehydrogenase by ATP
B. Inhibition of phosphofructokinase by citrate
C. Inhibition of isocitrate dehydrogenase by NADH
D. Activation of fatty acid synthesis from acetyl CoA
E. Reduction in the rate of conversion of glucose to pyruvate
A
Many prokaryotes carry out aerobic respiration. Which of the following statements about the aerobic oxidation of glucose in eukaryotic and prokaryotic cells is true?
A. The respiratory chain is located in the inner mitochondrial membrane of both eukaryotes and prokaryotes.
B. The citric acid cycle occurs in the cytoplasm of prokaryotes and eukaryotes.
C. Glycolysis takes place in the cytoplasm of prokaryotes and eukaryotes.
D. The electron transport chain is located in the plasma membrane of eukaryotes.
E. Pyruvate oxidation takes place in the cytoplasm of eukaryotes and prokaryotes.
C
NAD+ is
A. an oxidizing agent.
B. a reducing agent.
C. oxidized during glycolysis.
D. a dinucleotide.
E. Both A and D
E
reduction
the gain of electrons
ATP synthase
integral membrane protein that uses transport of protons to form ATP molecules from ADP and Pi
oxidation
the loss of electrons
redox rxn
rxn in which one reactant is oxidized and another is reduced
substrate-level phosphorylation
direct formation of ATP from ADP and a Pi that comes directly from a reactant
gluconeogenesis
synthesis of glucosef rom other substances, e.g. amino acids, lactate, and glycerol
proton-motive force
force generated across a membrane due to:
- chemical potential from difference in [H+]
- electrical potential due to electrostatic charge on H+
anaerobic
occuring without use of oxygen
allosteric regulation
regulation of protein/enzyme activity through binding a molecule to a site other than the active site
respiratory chain
terminal rxns in chemical respiration
electrons passed from NAD or FAD to molecular oxygen with accompanying production of ATP
pyruvate oxidation
(general process)
conversion of pyruvate to acetyl CoA and CO2
pyruvate oxidation
(location of occurence)
mitochondrial matrix
fermentation
anaerobic degradation of substance to smaller molecules through extraction of energy
e.g. glucose –> lactic acid or alcohol
citric acid cycle
set of chemical rxns in which acetyl CoA is oxidized to CO2 and hydrogen atoms are stored as NADH and FADH2
citric acid cycle
(synonym)
krebs cycle
(synonym)
pyruvate
3-carbon acid
end product of glycolysis
initial product of citric acid cycle
chemiosmosis
formation of ATP in mitochondria and chloroplasts due to pumping of protons across a membrane
aerobic
requiring oxygen
acetyl coenzyme A
(“abbreviation”)
acetyl CoA
(long form)
acetyl coenzyme A (acetyl CoA)
compound that reacts with oxaloacetate to produce citrate at beginning of citric acid cycle
key metabolic intermediate in formation of many compounds
oxidative phosphorylation
ATP formation in mitochondion associated with flow of electrons through repiratory chain
cellular respiration
catabolic pathways in which electrons are removed and passed through intermediate electron carriers to oxygen
generates water and releases energy
glycolysis
enzymatic breakdown of glucose to pyruvic acid
the gain of electrons
reduction
integral membrane protein that uses transport of protons to form ATP molecules from ADP and Pi
ATP synthase
the loss of electrons
oxidation
rxn in which one reactant is oxidized and another is reduced
redox rxn
direct formation of ATP from ADP and a Pi that comes directly from a reactant
substrate-level phosphorylation
synthesis of glucosef rom other substances, e.g. amino acids, lactate, and glycerol
gluconeogenesis
force generated across a membrane due to:
- chemical potential from difference in [H+]
- electrical potential due to electrostatic charge on H+
proton-motive force
occuring without use of oxygen
anaerobic
regulation of protein/enzyme activity through binding a molecule to a site other than the active site
allosteric regulation
terminal rxns in chemical respiration
electrons passed from NAD or FAD to molecular oxygen with accompanying production of ATP
respiratory chain
conversion of pyruvate to acetyl CoA and CO2
pyruvate oxidation
(general process)
anaerobic degradation of substance to smaller molecules through extraction of energy
e.g. glucose –> lactic acid or alcohol
fermentation
set of chemical rxns in which acetyl CoA is oxidized to CO2 and hydrogen atoms are stored as NADH and FADH2
citric acid cycle
krebs cycle
(synonym)
citric acid cycle
(synonym)
3-carbon acid
end product of glycolysis
initial product of citric acid cycle
pyruvate
formation of ATP in mitochondria and chloroplasts due to pumping of protons across a membrane
chemiosmosis
requiring oxygen
aerobic
acetyl CoA
(long form)
acetyl coenzyme A
(“abbreviation”)
compound that reacts with oxaloacetate to produce citrate at beginning of citric acid cycle
key metabolic intermediate in formation of many compounds
acetyl coenzyme A (acetyl CoA)
ATP formation in mitochondion associated with flow of electrons through repiratory chain
oxidative phosphorylation
catabolic pathways in which electrons are removed and passed through intermediate electron carriers to oxygen
generates water and releases energy
cellular respiration
enzymatic breakdown of glucose to pyruvic acid
glycolysis
