ch. 7 learning curve
The first phase of glycolysis requires the input of two ATP molecules. It is therefore: a. exergonic. b. endergonic. c. oxidative. d. reducing. e. None of the other answer options is correct.
b. endergonic.
Starting with glycolysis, lactic acid and ethanol fermentation generate only two ATP molecules per glucose molecule. The remaining chemical energy from the glucose is found primarily in: a. NADH. b. lactic acid and ethanol. c. FADH2. d. GTP. e. CO2.
b. lactic acid and ethanol.
During fermentation, pyruvate is: a. carboxylated. b. reduced. c. hydrogenated. d. oxidized. e. phosphorylated.
b. reduced.
Which of the following correctly characterizes the F1 subunit of ATP synthase? a. It is embedded in the inner mitochondrial membrane. b. It forms the channel through which protons flow. c. It is the catalytic unit that synthesizes ATP. d. None of the other answer options is correct.
c. It is the catalytic unit that synthesizes ATP.
When a single pyruvate is converted to acetyl-CoA, the other products of the reaction are: a. ATP and NADH. b. Pi and FADH2. c. NADH and CO2. d. CO2 and ATP. e. FADH2 and ATP.
c. NADH and CO2.
The proteins of the electron transport chain are: a. embedded in the outer mitochondrial membrane. b. embedded in both mitochondrial membranes. c. embedded in the inner mitochondrial membrane. d. located in the intermembrane space of mitochondria. e. located in the mitochondrial matrix.
c. embedded in the inner mitochondrial membrane.
In what organelle is pyruvate oxidation carried out in a cell? a. nucleus b. chloroplast c. mitochondrion d. Golgi apparatus e. endoplasmic reticulum
c. mitochondrion
We consume a variety of carbohydrates that are digested into a variety of different sugars. How do these different sugars enter glycolysis? a. All sugars are converted to fructose 6-phosphate and enter glycolysis at phase 1, step 3. b. All sugars are converted to glyceraldehyde 3-phosphate and enter glycolysis at phase 3, step 6. c. All sugars are converted to glucose 6-phosphate and enter glycolysis at phase 1, step 2. d. Sugars are converted to various forms and enter glycolysis at various stages. e. None of the other answer options is correct.
d. Sugars are converted to various forms and enter glycolysis at various stages.
During pyruvate oxidation, pyruvate is broken down into CO2 and an acetyl group. The CO2 is: a. less oxidized than the acetyl group. b. more reduced than the acetyl group. c. more energetic than the acetyl group. d. less energetic than the acetyl group. e. None of the other answer options is correct.
d. less energetic than the acetyl group.
Which of the following does not occur during the third phase of glycolysis? a. the transfer of high-energy electrons to NAD+ b. pyruvate production c. ATP synthesis d. oxygen consumption e. None of the other answer options is correct.
d. oxygen consumption
During pyruvate oxidation, which of the following also occur(s)? a. the formation of NADH b. the oxidation of pyruvate c. the formation of acetyl-CoA d. the formation of CO2 e. All of these choices are correct.
e. All of these choices are correct.
Which of the following statements are true regarding pyruvate oxidation? a. This process occurs within the matrix of mitochondria. b. This process constitutes the second stage of cellular respiration. c. The process produces both CO2 and acetyl-CoA. d. The process yields no ATP via substrate-level phosphorylation. e. All of these choices are correct.
e. All of these choices are correct.
After pyruvate oxidation, the chemical energy of how many carbons of the original glucose molecule is converted to chemical energy in the form of ATP in the remaining steps of cellular respiration?
4
ATP is not generated directly in the citric acid cycle; instead, an intermediate is first generated by substrate-level phosphorylation. The intermediate is: GTP. acetyl-CoA. GDP. cAMP. oxaloacetate.
GTP.
Which best describes energy production during cellular respiration? a. A small amount of energy is produced by substrate-level phosphorylation; most is produced by oxidative phosphorylation. b. A small amount of energy is produced by oxidative phosphorylation; most is produced by substrate-level phosphorylation. c. An equal amount is produced by oxidative phosphorylation and substrate-level phosphorylation. d. It depends on the organism. Some produce most of their energy by substrate-level phosphorylation, and some produce most of their energy by oxidative phosphorylation. e. None of the other answer options is correct.
a. A small amount of energy is produced by substrate-level phosphorylation; most is produced by oxidative phosphorylation.
Which of the following statements is true regarding the proton gradient? a. It is synonymous with the "electrochemical gradient." b. It contains a great deal of kinetic energy. c. It results from differences in the concentration of hydroxide ions. d. It results from a combination of "neutral" charges. e. None of the other answer options is correct.
a. It is synonymous with the "electrochemical gradient."
Which of the following statements is true regarding a reducing agent? a. It loses electrons. b. It is usually oxygen. c. It gains electrons. d. It is an electron acceptor. e. It is never oxidized.
a. It loses electrons.
The inputs to glycolysis do not include: a. NADH. b. ADP. c. NAD+. d. glucose. e. Pi.
a. NADH.
Which of the following statements is true regarding pyruvate oxidation? a. Pyruvate oxidation forms the same number of NADH (per glucose molecule) as glycolysis. b. Like glycolysis, pyruvate oxidation is carried out in the mitochondria. c. Pyruvate oxidation ends with the oxidation of an acetyl group, which forms CO2. d. Pyruvate oxidation directly follows the citric acid cycle during cellular respiration.
a. Pyruvate oxidation forms the same number of NADH (per glucose molecule) as glycolysis.
Lactic acid fermentation occurs in: Select all that apply. a. bacteria and animals. b. fungi and bacteria. c. animals and fungi. d. animals and plants. e. plants and bacteria.
a. bacteria and animals.
The breakdown of fatty acids takes place by a process called: a. beta-oxidation. b. pyruvate oxidation. c. glycolysis. d. electron transport. e. oxidative phosphorylation.
a. beta-oxidation.
In cellular respiration, oxygen: a. gains electrons and is an oxidizing agent. b. loses electrons and is a reducing agent. c. gains electrons and is a reducing agent. d. loses electrons and is an oxidizing agent. e. None of the other answer options is correct.
a. gains electrons and is an oxidizing agent.
Pyruvate oxidation is an important stage in cellular respiration because: a. it links glycolysis with the citric acid cycle. b. it eliminates toxic pyruvate from the cell. c. it generates ATP by substrate-level phosphorylation. d. it transfers large numbers of electrons to electron carriers. e. it is the first step in oxidative phosphorylation.
a. it links glycolysis with the citric acid cycle.
In the second phase of glycolysis: a. phosphorylated sugar molecule is cleaved and the products rearranged. b. phosphate groups are added to glucose. c. ATP is generated by oxidative phosphorylation. d. ATP is generated by substrate-level phosphorylation. e. NAD+ is reduced to NADH.
a. phosphorylated sugar molecule is cleaved and the products rearranged.
The _____ forms of the electron carriers NAD+/NADH and FADH/FADH2 have high potential energy. oxidized a. reduced b. phosphorylated c. carboxylated e. None of the other answer options is correct.
a. reduced
Fermentation occurs in: a. some aerobic organisms, such as yeast, even in the presence of oxygen. b. anaerobic organisms only. c. only in bacteria and plants.
a. some aerobic organisms, such as yeast, even in the presence of oxygen.
Coenzyme Q and cytochrome c: a. transfer electrons between protein complexes of the electron transport chain. b. transfer high-energy electrons from NADH and FADH2 to protein complexes of the electron transport chain. c. transfer electrons to ATP synthase. d. transfer electrons to oxygen at the end of the electron transport chain. e. None of the other answer options is correct.
a. transfer electrons between protein complexes of the electron transport chain.
At the end of glycolysis, the carbon molecules originally found in the starting glucose molecule are in the form of: a. two pyruvate molecules. b. four ATP molecules. c. one pyruvate molecule. d. two NADH molecules. e. two ATP molecules.
a. two pyruvate molecules.
For the potential energy of a proton gradient to be converted to the chemical energy of ATP, the movement of protons down their electrochemical gradient must be coupled with ATP synthesis. This coupling is made possible by: a. coenzyme Q. b. ATP synthase. c. cytochrome c. d. oxygen. e. protein complex IV.
b. ATP synthase.
Glycolysis is: a. aerobic. b. anaerobic. c. aerobic in some organisms but anaerobic in others. d. aerobic in some tissues but anaerobic in others. e. None of the other answer options is correct.
b. anaerobic.
How did the earliest organisms on Earth most likely produce ATP? a. by pyruvate oxidation b. by glycolysis c. by the citric acid cycle d. by oxidative phosphorylation
b. by glycolysis
Cellular respiration is a series of _____ reactions. a. anabolic b. catabolic c. glycolytic d. phosphorylation e. carboxylation
b. catabolic
An important aspect of biology is that many proteins are used in several different processes. Which of the following protein complexes is used in both the electron transport chain and the citric acid cycle? a. complex I b. complex II c. complex III d. complex IV e. ATP synthase
b. complex II
Phosphorylating glucose during phase 1 of glycolysis: a. releases phosphorylated glucose from cells. b. destabilizes the glucose molecule so that it can be broken down in phase 2. c. provides electrons to reduce NAD+ in phase 3. d. provides electrons to reduce FADH in phase 3. e. None of the other answer options is correct.
b. destabilizes the glucose molecule so that it can be broken down in phase 2.
Which stage of cellular respiration occurs immediately after pyruvate is produced? a. glycolysis b. pyruvate oxidation c. citric acid cycle d. electron transport e. oxidative phosphorylation
b. pyruvate oxidation
We can tell from their structure that fatty acids are a good source of energy because of: a. the high potential energy of the carboxylic acid group. b. the large number of carbon-carbon and carbon-hydrogen bonds they contain. c. their hydrophobic nature conferred by their chemical formula. d. their three-dimensional bonding structure. e. None of the other answer options is correct.
b. the large number of carbon-carbon and carbon-hydrogen bonds they contain.
Lactic acid and ethanol fermentation differ in that: a. NADH is oxidized to NAD+ in lactic acid fermentation, but FADH2 is oxidized to FADH in ethanol fermentation. b. ethanol fermentation produces ATP by substrate level phosphorylation, but lactic acid fermentation does not. c. Ethanol fermentation produces CO2, but lactic acid fermentation does not. d. FADH2 is oxidized to FADH in lactic acid fermentation, but NADH is oxidized to NAD+ in ethanol fermentation. e. lactic acid fermentation produces ATP by substrate level phosphorylation, but ethanol fermentation does not.
c. Ethanol fermentation produces CO2, but lactic acid fermentation does not.
The chemical bonds of carbohydrates and lipids have high potential energy because: a. they are strong reducing agents. b. they are strong oxidizing agents. c. many of these bonds are C—C and C—H bonds. d. they are easy to phosphorylate. e. they are easy to hydrolyze.
c. many of these bonds are C—C and C—H bonds.
The citric acid cycle is a cycle because the starting molecule, _____, is regenerated at the end. a. acetyl-CoA b. citrate c. oxaloacetate d. fructose 6-diphosphate e. pyruvate
c. oxaloacetate
The electron transport chain is part of: a. glycolysis. b. the citric acid cycle. c. oxidative phosphorylation. d. pyruvate oxidation. e. fermentation.
c. oxidative phosphorylation.
During the citric acid cycle: a. fuel molecules are completely reduced. b. high-energy electrons are removed from NAD+ and FADH. c. ATP is synthesized by oxidative phosphorylation. d. ATP is synthesized by substrate-level phosphorylation.
d. ATP is synthesized by substrate-level phosphorylation.
Which of the following statements is true regarding the equation C6H12O6 + 6O2 →6CO2+ 6H2O + energy? a. In the production of CO2 from glucose, the oxygen atoms lose electrons and the carbon atom is oxidized. b. The oxygen atoms in both CO2 and H2O are electronegative. c. Glucose could be considered a reducing agent. d. The oxygen atoms in both CO2 and H2O are electronegative, and glucose is considered a reducing agent. e. The movement of hydrogen atoms in reactions involving C6H12O6 and H2O yields no information regarding the movement of electrons.
d. The oxygen atoms in both CO2 and H2O are electronegative, and glucose is considered a reducing agent.
During what phase of glycolysis is NADH formed? a. during phase 1, when fructose 1,6-biphosphate is formed b. during phase 2, when glyceraldehyde 3-phosphate is formed c. during phase 3, when pyruvate is finally formed d. during phase 3, when glyceraldehyde 3-phosphate is phosphorylated e. during phase 1, when glucose is phosphorylated
d. during phase 3, when glyceraldehyde 3-phosphate is phosphorylated
The majority of the energy generated in the citric acid cycle is in the form of: a. ATP produced by substrate-level phosphorylation. b. GTP produced by substrate-level phosphorylation. c. GTP produced by oxidative phosphorylation. d. electrons donated to NAD+ and FAD+. e. ATP produced by oxidative phosphorylation.
d. electrons donated to NAD+ and FAD+.
Imagine that a eukaryotic cell carries a mutation impairing its ability to phosphorylate glucose during glycolysis. What is a likely result of this mutation? a. Because phosphorylation stabilizes glucose, glucose would spontaneously form pyruvate. b. High (possibly toxic) levels of glucose would accumulate in the cell. c. Without the phosphorylation of glucose, glycolysis would consist entirely of exergonic reactions. d. More pyruvate would be formed at the end of glycolysis. e. Glucose could move out of the cell, slowing cellular respiration.
e. Glucose could move out of the cell, slowing cellular respiration.
Which of the following statements is true regarding aerobic respiration? Aerobic respiration requires oxygen at every stage of the process. Aerobic respiration is carried out by all prokaryotes and eukaryotes. Aerobic respiration is a three-stage process, with oxidative phosphorylation comprising the last stage. Carbon dioxide is produced at every stage of aerobic respiration. None of the other answer options is correct.
e. None of the other answer options is correct.
Which of the following statements is true regarding pyruvate and glucose? a. Glucose easily passes in and out of mitochondria, and can often be found in the mitochondrial matrix. b. Pyruvate is typically "trapped" in the intermembrane space of mitochondria, where it is oxidized to form acetyl-CoA. c. Glucose and pyruvate are remarkably similar in structure, with both molecules possessing a ring shape. d. Both glucose and pyruvate can feed directly into the citric acid cycle, although acetyl-CoA is the preferred reactant for this process. e. None of the other answer options is correct.
e. None of the other answer options is correct.
The citric acid cycle takes place in the: a. outer mitochondrial membrane. b. intermembrane space of mitochondria. c. cytoplasm. d. inner mitochondrial membrane. e. mitochondrial matrix.
e. mitochondrial matrix.
By the time pyruvate is formed, most of the energy contained in glucose has been released. T or F?
false
During the action of ATP synthase, the kinetic energy of the proton gradient is transformed into potential energy. T or F?
false
Fermentation produces nearly two times as much ATP as aerobic respiration, which explains why it is a preferred pathway for bacteria. T or F?
false
In a plant cell, all stages of cellular respiration are carried out in the cytoplasm. T or F?
false
Like glycolysis, pyruvate oxidation produces both pyruvate and acetyl-CoA. These two products feed directly into the citric acid cycle and are the reactants for the cycle. T or F?
false
Malate is both the starting and ending product of the citric acid cycle. true false
false
Oxidation is the gain of electrons. T or F?
false
Pyruvate oxidation is remarkably similar to glycolysis in that when one molecule of pyruvate enters into a mitochondrion, two molecules of acetyl-CoA are formed. T or F?
false
Pyruvate oxidation produces a large amount of ATP. t or f?
false
The majority of cells within the human body have a very high baseline amount of ATP, so cells are always prepared for any long-term activity. T or F?
false
When glucose is broken down in a cell, all of the energy it stores is released simultaneously, not in a stepwise process. T or F?
false
Excess glucose is stored in large branched molecules of:
glycogen in animals
_____ is found in animals, and possesses a large, central protein. _____ is found in plants, and lacks a central protein.
glycogen, starch
In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water.
oxidized; reduced
Another name for acetyl-CoA synthesis, is:
pyruvate oxidation.
Although cellular respiration is typically thought of as an aerobic process, glycolysis itself is actually anaerobic. T or F?
true
The ATP produced during glycolysis is the result of substrate-level phosphorylation. true false
true
The majority of organisms on Earth can carry out some form of glycolysis. T or F?
true
