chapter seven : Cellular Respiration: Harvesting Energy from Carbohydrates and Other Fuel Molecules

Once they have been processed through the citric acid cycle, the acetyl-CoA molecules from a single glucose molecule produce: 4 CO2, 6 FADH2, 2 ATP. 6 FADH2, 2 ATP, 6 CO2. 6 NADH, 6 GTP. 6 GTP, 6 FADH2. 2 ATP, 6 NADH, 4 CO2.

2 ATP, 6 NADH, 4 CO2.

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. True or False

False

When a single pyruvate is converted to acetyl-CoA, the other products of the reaction are: NADH and CO2. Pi and FADH2. ATP and NADH. CO2 and ATP. FADH2 and ATP.

NADH and CO2.

Fermentation produces nearly two times as much ATP as aerobic respiration, which explains why it is a preferred pathway for bacteria. true false

false

In a plant cell, all stages of cellular respiration are carried out in the cytoplasm. True or False

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. true false

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. true false

false

In cellular respiration, oxygen: gains electrons and is an oxidizing agent. loses electrons and is a reducing agent. gains electrons and is a reducing agent. loses electrons and is an oxidizing agent. None of the other answer options is correct.

gains electrons and is an oxidizing agent.

Fermentation takes place: in the mitochondrial matrix. on the outer mitochondrial membrane. in the cytoplasm. in the intermembrane space of mitochondria. on the inner mitochondrial membrane.

in the cytoplasm

Due to the pumping action of the electron transport chain, protons have a high concentration in the _____ and a low concentration in the _____. mitochondrial matrix; cytoplasm intermembrane space; cytoplasm mitochondrial matrix; intermembrane space mitochondrial matrix; extracellular fluid intermembrane space; mitochondrial matrix

intermembrane space; mitochondrial matrix

Imagine that you exhale after a deep breath. Which of the following are you not exhaling? waste products of both pyruvate oxidation and the citric acid cycle waste products of glycolysis waste products of the citric acid cycle waste products of pyruvate oxidation CO2

waste products of glycolysis

Another name for acetyl-CoA synthesis, is: pyruvate reduction. glycolysis. pyruvate oxidation. oxidative phosphorylation. substrate-level phosphorylation.

pyruvate oxidation.

During fermentation, pyruvate is: carboxylated. hydrogenated. oxidized. reduced. phosphorylated.

reduced

The _____ forms of the electron carriers NAD+/NADH and FADH/FADH2 have high potential energy. oxidized reduced phosphorylated carboxylated None of the other answer options is correct.

reduced

Which best describes energy production during cellular respiration? A small amount of energy is produced by substrate-level phosphorylation; most is produced by oxidative phosphorylation. A small amount of energy is produced by oxidative phosphorylation; most is produced by substrate-level phosphorylation. An equal amount is produced by oxidative phosphorylation and substrate-level phosphorylation. 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. None of the other answer options is correct.

A small amount of energy is produced by substrate-level phosphorylation; most is produced by oxidative phosphorylation.

The enzyme phosphofructokinase-1 (PFK-1) is thought of as a metabolic "valve" that regulates the rate of glycolysis. Which of the following correctly identifies its allosteric activators and inhibitors and their actions? AMP—activator; CoQ—inhibitor CoQ—activator; citrate—inhibitor ADP—activator; ATP—activator ATP—activator; AMP—inhibitor ADP—activator; citrate—inhibitor

ADP—activator; citrate—inhibitor

During pyruvate oxidation, which of the following also occur(s)? the formation of NADH the oxidation of pyruvate the formation of acetyl-CoA the formation of CO2 All of these choices are correct.

All of these choices are correct.

Which of the following statements are true regarding pyruvate oxidation? This process occurs within the matrix of mitochondria. This process constitutes the second stage of cellular respiration. The process produces both CO2 and acetyl-CoA. The process yields no ATP via substrate-level phosphorylation. All of these choices are correct.

All of these choices are correct.

Malate is both the starting and ending product of the citric acid cycle. True or False

False

Pyruvate oxidation produces a large amount of ATP. True or False

False

Imagine that a eukaryotic cell carries a mutation impairing its ability to phosphorylate glucose during glycolysis. What is a likely result of this mutation? Because phosphorylation stabilizes glucose, glucose would spontaneously form pyruvate. Glucose could move out of the cell, slowing cellular respiration. High (possibly toxic) levels of glucose would accumulate in the cell. Without the phosphorylation of glucose, glycolysis would consist entirely of exergonic reactions. More pyruvate would be formed at the end of glycolysis.

Glucose could move out of the cell, slowing cellular respiration.

You may be familiar with the story of Philippides, the famous Greek runner who ran the first marathon and then died after completing his run. Based on what you know of aerobic respiration and fermentation, why might Philippides have died? His muscles may have produced toxic levels of ethanol, causing his blood to become more acidic. His muscles may have produced toxic levels of lactic acid, causing his blood to become more acidic. His muscles may have produced toxic levels of ethanol, causing his blood to become more basic. His muscles may have produced toxic levels of both ethanol and lactic acid, causing his blood to become more acidic. His muscles may have produced toxic levels of lactic acid, causing his blood to become more basic.

His muscles may have produced toxic levels of lactic acid, causing his blood to become more acidic.

The inputs to glycolysis do not include: Pi. NADH. ADP. NAD+. glucose.

NADH

Which of the following statements is true regarding the proton gradient? It is synonymous with the "electrochemical gradient." It contains a great deal of kinetic energy. It results from differences in the concentration of hydroxide ions. It results from a combination of "neutral" charges. None of the other answer options is correct.

It is synonymous with the "electrochemical gradient."

Which of the following statements is true regarding a reducing agent? It gains electrons. It is never oxidized. It loses electrons. It is an electron acceptor. It is usually oxygen

It loses electrons.

Which of the following statements is true regarding pyruvate and glucose? Glucose easily passes in and out of mitochondria, and can often be found in the mitochondrial matrix. Pyruvate is typically "trapped" in the intermembrane space of mitochondria, where it is oxidized to form acetyl-CoA. Glucose and pyruvate are remarkably similar in structure, with both molecules possessing a ring shape. Both glucose and pyruvate can feed directly into the citric acid cycle, although acetyl-CoA is the preferred reactant for this process. None of the other answer options is correct.

None of the other answer options is correct.

Which of the following statements is true regarding pyruvate oxidation? Like glycolysis, pyruvate oxidation is carried out in the mitochondria. Pyruvate oxidation forms the same number of NADH (per glucose molecule) as glycolysis. Pyruvate oxidation directly follows the citric acid cycle during cellular respiration. Pyruvate oxidation ends with the oxidation of an acetyl group, which forms CO2.

Pyruvate oxidation forms the same number of NADH (per glucose molecule) as glycolysis.

Which of the following statements is true regarding the equation C6H12O6 + 6O2 →6CO2+ 6H2O + energy? The oxygen atoms in both CO2 and H2O are electronegative, and glucose is considered a reducing agent. The movement of hydrogen atoms in reactions involving C6H12O6 and H2O yields no information regarding the movement of electrons. The oxygen atoms in both CO2 and H2O are electronegative. In the production of CO2 from glucose, the oxygen atoms lose electrons and the carbon atom is oxidized. Glucose could be considered a reducing agent.

The oxygen atoms in both CO2 and H2O are electronegative, and glucose is considered a reducing agent.

A researcher is studying a population of bacteria that carry out the citric acid cycle, but do so in reverse. What statements are likely true of these bacteria? Please choose the correct answer from the following choices, and then select the submit answer button. These bacteria will release CO2 as a waste product. An individual bacterium will produce most of its energy by means of the citric acid cycle. These bacteria will release CO2 as a waste product and will carry out cellular respiration within their mitochondria. These bacteria will produce sugars from intermediates of the citric acid cycle. These bacteria carry out cellular respiration in their mitochondria.

These bacteria will produce sugars from intermediates of the citric acid cycle.

Energy released by transferring electrons along the electron transport chain is stored as potential energy in the form of: ATP. coenzyme Q. a proton gradient. redox couples. ATP synthase.

a proton gradient.

Lactic acid fermentation occurs in: plants and bacteria. animals and plants. fungi and bacteria. animals and fungi. bacteria and animals.

bacteria and animals.

The breakdown of fatty acids takes place by a process called: electron transport. oxidative phosphorylation. pyruvate oxidation. beta-oxidation. glycolysis.

beta-oxidation.

How did the earliest organisms on Earth most likely produce ATP? by oxidative phosphorylation by pyruvate oxidation by the citric acid cycle by glycolysis

by glycolysis

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? complex I complex II complex III complex IV ATP synthase

complex II

Phosphorylating glucose during phase 1 of glycolysis: releases phosphorylated glucose from cells. destabilizes the glucose molecule so that it can be broken down in phase 2. provides electrons to reduce NAD+ in phase 3. provides electrons to reduce FADH in phase 3. None of the other answer options is correct.

destabilizes the glucose molecule so that it can be broken down in phase 2.

In the first three stages of cellular respiration, the chemical energy in glucose is transferred to: cytochrome b and coenzyme Q. only coenzyme Q. electron carriers and ATP. ATP and cytochrome b. proton pumps and ATP.

electron carriers and ATP.

Pyruvate oxidation is an important stage in cellular respiration because: it is the first step in oxidative phosphorylation. it eliminates toxic pyruvate from the cell. it links glycolysis with the citric acid cycle. it generates ATP by substrate-level phosphorylation. it transfers large numbers of electrons to electron carriers.

it links glycolysis with the citric acid cycle.

During pyruvate oxidation, pyruvate is broken down into CO2 and an acetyl group. The CO2 is: Please choose the correct answer from the following choices, and then select the submit answer button. less oxidized than the acetyl group. more reduced than the acetyl group. more energetic than the acetyl group. less energetic than the acetyl group. None of the other answer options is correct.

less energetic than the acetyl group.

The chemical bonds of carbohydrates and lipids have high potential energy because: many of these bonds are C—C and C—H bonds. they are easy to hydrolyze. they are strong reducing agents. they are easy to phosphorylate. they are strong oxidizing agents.

many of these bonds are C—C and C—H bonds.

In what organelle is pyruvate oxidation carried out in a cell? endoplasmic reticulum mitochondrion chloroplast Golgi apparatus nucleus

mitochondrion

In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water. deoxygenated; phosphorylated oxidized; oxidized reduced; oxidized phosphorylated; deoxygenated oxidized; reduced

oxidized; reduced

Which of the following does not occur during the third phase of glycolysis? None of the other answer options is correct. oxygen consumption ATP synthesis pyruvate production the transfer of high-energy electrons to NAD+

oxygen consumption

The final electron acceptor of the electron transport chain is: NAD+. ATP synthase. cytochrome C. coenzyme Q. oxygen.

oxygen.

In the second phase of glycolysis: ATP is generated by substrate-level phosphorylation. ATP is generated by oxidative phosphorylation. NAD+ is reduced to NADH. phosphorylated sugar molecule is cleaved and the products rearranged. phosphate groups are added to glucose.

phosphorylated sugar molecule is cleaved and the products rearranged.

Which stage of cellular respiration occurs immediately after pyruvate is produced? glycolysis pyruvate oxidation citric acid cycle electron transport oxidative phosphorylation

pyruvate oxidation

Fermentation occurs in: anaerobic organisms only. only in bacteria and plants. some aerobic organisms, such as yeast, even in the presence of oxygen.

some aerobic organisms, such as yeast, even in the presence of oxygen.

In glycolysis, ATP is synthesized by: electron carriers. both substrate level and oxidative phosphorylation. substrate-level phosphorylation. oxidative phosphorylation. redox reactions.

substrate-level phosphorylation.

Which is the only reaction in the citric acid cycle that produces ATP by substrate-level phosphorylation? the formation of oxaloacetate the formation of citrate the formation of succinate the formation of malate the formation of fumarate

the formation of succinate

We can tell from their structure that fatty acids are a good source of energy because of: the high potential energy of the carboxylic acid group. the large number of carbon-carbon and carbon-hydrogen bonds they contain. their hydrophobic nature conferred by their chemical formula. their three-dimensional bonding structure. None of the other answer options is correct.

the large number of carbon-carbon and carbon-hydrogen bonds they contain.

Recall that the citric acid cycle starts with a four-carbon molecule, but that most of its intermediates are molecules that contain six carbons. How is this possible? through the reaction of citrate and cis-aconitate through the reaction of malate and fumarate through the reaction of malate and oxaloacetate through the reaction of succinate and succinyl-CoA through the reaction of acetyl-CoA and oxaloacetate

through the reaction of acetyl-CoA and oxaloacetate

Coenzyme Q and cytochrome c: transfer electrons between protein complexes of the electron transport chain. transfer high-energy electrons from NADH and FADH2 to protein complexes of the electron transport chain. transfer electrons to ATP synthase. transfer electrons to oxygen at the end of the electron transport chain. None of the other answer options is correct.

transfer electrons between protein complexes of the electron transport chain.

Although cellular respiration is typically thought of as an aerobic process, glycolysis itself is actually anaerobic. true false

true

Although glycolysis produces four molecules of ATP by substrate-level phosphorylation, the net gain of ATP for the cell is two molecules. This is due to the fact that glycolysis is—at first—endergonic. true false

true

The ATP produced during glycolysis is the result of substrate-level phosphorylation. true false

true