Chapter 9 MasteringBio

Starting with one molecule of glucose, the energy-containing products of glycolysis are _____. 2 NADH, 2 pyruvate, and 2 ATP 2 FADH2, 2 pyruvate, and 4 ATP 2 NAD+, 2 pyruvate, and 2 ATP 6 CO2, 2 pyruvate, and 2 ATP

2 NADH, 2 pyruvate, and 2 ATP

Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration? 4 30-32 2 18-24

30-32

Which of the listed statements describes the results of the following reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy C6H12O6 is oxidized and O2 is reduced. CO2 is reduced and O2 is oxidized. O2 is reduced and CO2 is oxidized. O2 is oxidized and H2O is reduced.

C6H12O6 is oxidized and O2 is reduced

A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen when an athlete exhausts his or her ATP supply? He or she has to sit down and rest. Other cells take over, and the muscle cells that have used up their ATP cease to function. Catabolic processes are activated that generate more ATP. ATP is transported into the cell from the circulatory system.

Catabolic processes are activated that generate more ATP

Select the correct statement about cellular respiration. Cellular respiration and breathing differ in that cellular respiration is at the cellular level, whereas breathing is at the organismal level. Animals carry out cellular respiration whereas plants carry out photosynthesis. Plants carry out cellular respiration only in organs such as roots that cannot carry out photosynthesis.

Cellular respiration and breathing differ in that cellular respiration is at the cellular level, whereas breathing is at the organismal level

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level? ATP NADH FADH2 ADP + Pi

FADH2

In the combined processes of glycolysis and cellular respiration, what is consumed and what is produced? ATP is consumed, and oxygen is produced. Carbon dioxide is consumed, and water is produced. Water is consumed, and ATP is produced. Glucose is consumed, and carbon dioxide is produced. Oxygen is consumed, and glucose is produced.

Glucose is consumed, and carbon dioxide is produced.

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the flow of electrons down the electron transport chain. H+ concentration across the membrane holding ATP synthase. affinity of oxygen for electrons. transfer of phosphate to ADP. oxidation of glucose and other organic compounds.

H+ concentration across the membrane holding ATP synthase

A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose? It is stored in NADH and FADH2 It is stored in the carbon dioxide and water molecules released by these processes. It was lost as heat. It is stored in pyruvate. It is stored in the ATP that was formed by glycolysis and the citric acid cycle.

It is stored in NADH and FADH2

Which of the following describes the process of glycolysis? It represents the first stage in the chemical oxidation of glucose by a cell. It requires ATP and NADH. Glycolysis produces 30 ATP from each molecule of glucose. It converts one glucose molecule to two molecules of pyruvate and carbon dioxide. Glycolysis occurs in the mitochondria

It represents the first stage in the chemical oxidation of glucose by a cell

The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mol and the free energy for the reduction of NAD+ to NADH is +53 kcal/mol. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed? Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis. Glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat. There is no CO2 or water produced as products of glycolysis. Most of the free energy available from the oxidation of glucose is used in the production of ATP in glycolysis.

Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis

Which of the following statements about NAD+ is true? NAD+ has more chemical energy than NADH. NAD+ can donate electrons for use in oxidative phosphorylation. In the absence of NAD+, glycolysis can still function. NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.

NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle

Given what you know about glycolysis and regulation of metabolism by PFK, what is the likely mechanism by which PFK activity differs depending on ATP concentration? PFK is an allosteric enzyme that is inhibited by ADP and stimulated by ATP. PFK is an allosteric enzyme that is stimulated by AMP, ADP, and ATP. PFK is an allosteric enzyme that is inhibited by AMP, ADP, and ATP. PFK is an allosteric enzyme that is inhibited by ATP and stimulated by AMP.

PFK is an allosteric enzyme that is inhibited by ATP and stimulated by AMP

Phosphofructokinase (PFK) is an enzyme that acts on fructose 6-phosphate at an early step in glucose breakdown. Regulation of this enzyme controls whether the sugar will continue on in the glycolytic pathway. Based on the graph, is PFK more active at low or high ATP concentration? PFK is more active at high ATP concentration. PFK activity is the same at low and high ATP concentration.

PFK is more active at low ATP concentration

In cellular respiration, a series of molecules forming an electron transport chain alternately accepts and then donates electrons. What is the advantage of such an electron transport chain? The advantage of an electron transport chain is the production of a large number of reduced, high-energy intermediates. The advantage of the respiratory electron transport chain is that oxygen is the final electron acceptor. The advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates.

The advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates

Identify all correct statements about the basic function of fermentation. The basic function of fermentation is the regeneration of NAD+, which allows continued ATP production by glycolysis. The basic function of fermentation is the production of ethyl alcohol or lactic acid. The basic function of fermentation is the production of additional ATP by further oxidation of the products of glycolysis.

The basic function of fermentation is the regeneration of NAD+, which allows continued ATP production by glycolysis

In most cells, not all of the carbon compounds that participate in glycolysis and the citric acid cycle are converted to carbon dioxide by cellular respiration. What happens to the carbon in these compounds that does not end up as CO2? They are used to make ATP from NADH. The carbon compounds are removed from these processes to serve as building blocks for other complex molecules. They are used to make NADH. These carbon compounds are used to convert ADP to ATP via chemiosmosis. They are converted to heat energy.

The carbon compounds are removed from these processes to serve as building blocks for other complex molecules

Which of the following statements about the chemiosmotic synthesis of ATP is correct? The energy for production of ATP from ADP comes directly from a gradient of electrons across the inner mitochondrial membrane. Oxygen participates directly in the reaction that makes ATP from ADP and P. The chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane. The chemiosmotic synthesis of ATP occurs only in eukaryotic cells, because it occurs in mitochondria. Chemiosmotic ATP synthesis requires oxygen.

The chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane

Which of the following statements accurately describes the function of a metabolic pathway involved in cellular respiration? The function of the bonding of acetic acid to the carrier molecule CoA to form acetyl CoA is the reduction of glucose to acetyl CoA. The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP. The function of the citric acid cycle is the transfer of electrons from pyruvate to NADH to O2.

The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP

How will a healthy individual's ATP production change during an eight-hour fast? The individual's ATP production will decrease significantly. The individual's ATP production will increase significantly. The individual's ATP production will not change significantly.

The individual's ATP production will not change significantly

Which statement about the citric acid cycle is correct? The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle. The citric acid cycle produces most of the ATP that is subsequently used by the electron transport chain. The citric acid cycle oxidizes glucose to carbon dioxide. The oxidation of compounds by the citric acid cycle requires molecular oxygen. The citric acid cycle depends on the availability of NAD+, which is a product of glycolysis.

The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? NAD+ is oxidized. The pH of the matrix increases. ATP synthase pumps protons by active transport. The electrons gain free energy. The cytochromes phosphorylate ADP to form ATP.

The pH of the matrix increases

Which one of the following statements about the redox reactions of the electron transport chain is correct? The electron transport chain takes electrons from water and gives them to oxygen. The oxidation of NADH is directly coupled to the reduction of oxygen to water. The redox reactions of the electron transport chain are directly coupled with the synthesis of ATP. NADH gains electrons in the initial reaction of the electron transport chain. The redox reactions of the electron transport chain are directly coupled to the movement of protons across

The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane

ATP synthase is a key enzyme of mitochondrial energy conversion. Mitochondrial ATP synthase deficiency is due to a mutation in a gene important for the formation of a subunit in the ATP synthase complex. Scientists could use cells with this gene mutation to investigate which of the following questions? What effect does the mutation have on the amount of ATP synthesized during cellular respiration? What effect does the mutation have on the number of water molecules formed at the end of the electron transport chain? What effect does the mutation have on the number of protons pumped into the intermembrane space of the mitochondria? What effect does the mutation have on the movement of electrons between the electron carriers of the electron transport chain?

What effect does the mutation have on the amount of ATP synthesized during cellular respiration?

The oxygen consumed during cellular respiration is involved directly in which process or event? he oxidation of pyruvate to acetyl CoA accepting electrons at the end of the electron transport chain glycolysis the citric acid cycle

accepting electrons at the end of the electron transport chain

Even though plants cells photosynthesize, they still use their mitochondria for oxidation of pyruvate. This will occur in _____. photosynthesizing cells in the light and in other tissues in the dark all cells all the time cells that are storing glucose only photosynthetic cells in the light, while photosynthesis occurs concurrently

all cells all the time

High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location from the active site. This is an example of _____. positive feedback regulation allosteric regulation competitive inhibition the specificity of enzymes for their substrates

allosteric regulation

Which kind of metabolic poison would most directly interfere with glycolysis? an agent that reacts with oxygen and depletes its concentration in the cell an agent that reacts with NADH and oxidizes it to NAD+ an agent that closely mimics the structure of glucose but is not metabolized an agent that binds to pyruvate and inactivates it

an agent that closely mimics the structure of glucose but is not metabolized

Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal "inside out." The little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. These inside-out membrane vesicles will _____. become acidic inside the vesicles when NADH is added hydrolyze ATP to pump protons out of the interior of the vesicle to the exterior become alkaline inside the vesicles when NADH is added make ATP from ADP and i if transferred to a pH 4 buffered solution after incubation in a pH 7 buffered solution

become acidic inside the vesicles when NADH is added

Yeast cells that have defective mitochondria incapable of respiration will be able to grow by catabolizing which of the following carbon sources for energy? fatty acids glucose proteins Such yeast cells will not be capable of catabolizing any food molecules, and therefore, will die.

glucose

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? the citric acid cycle reduction of pyruvate to lactate glycolysis the electron transport chain synthesis of acetyl CoA from pyruvate

glycolysis

Which of the following occurs in the cytosol of a eukaryotic cell? fermentation and chemiosmosis oxidation of pyruvate to acetyl CoA glycolysis and fermentation citric acid cycle

glycolysis and fermentation

Carbohydrates and fats are considered high-energy foods because they _____. have no nitrogen in their makeup. have a lot of electrons associated with hydrogen. are easily reduced. have a lot of oxygen atoms.

have a lot of electrons associated with hydrogen

The chemiosmotic hypothesis is an important concept in our understanding of cellular metabolism in general because it explains _____. the sequence of the electron transport chain molecules the reduction of oxygen to water in the final steps of oxidative metabolism how electron transport can fuel substrate-level phosphorylation how ATP is synthesized by a proton motive force

how ATP is synthesized by a proton motive force

Substrate-level phosphorylation occurs _____. during oxidative phosphorylation in glycolysis in the citric acid cycle in both glycolysis and the citric acid cycle

in both glycolysis and the citric acid cycle

The electron transport chain _____. is driven by ATP consumption is a series of redox reactions takes place in the cytoplasm of prokaryotic cells is a series of substitution reactions

is a series of redox reactions

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction _____. loses electrons and gains potential energy gains electrons and gains potential energy gains electrons and loses potential energy loses electrons and loses potential energy

loses electrons and loses potential energy

Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells? mitochondrial intermembrane space mitochondrial outer membrane mitochondrial matrix mitochondrial inner membrane

mitochondrial intermembrane space

One function of both alcohol fermentation and lactic acid fermentation is to _____. reduce FADH2 to FAD+ reduce NAD+ to NADH oxidize NADH to NAD+ reduce FAD+ to FADH2

oxidize NADH to NAD+

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes _____. an oxidizing agent oxidized reduced hydrolyzed

oxidized

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is water. NAD+. pyruvate. oxygen. ADP.

oxygen

In mitochondria, exergonic redox reactions provide the energy that establishes the proton gradient. are the source of energy driving prokaryotic ATP synthesis. are directly coupled to substrate-level phosphorylation. reduce carbon atoms to carbon dioxide. are coupled via phosphorylated intermediates to endergonic processes.

provide the energy that establishes the proton gradient

What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate + NAD+ pyruvate NADH lactate NAD+

pyruvate

What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate + NAD+ NAD+ NADH oxygen pyruvate lactate

pyruvate

When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes _____. oxidized redoxed reduced dehydrogenated

reduced

When electrons move closer to a more electronegative atom, what happens? The more electronegative atom is _____. reduced, and energy is consumed oxidized, and energy is released reduced, and energy is released oxidized, and energy is consumed

reduced, and energy is released

Most CO2 from catabolism is released during glycolysis. oxidative phosphorylation. electron transport. the citric acid cycle. lactate fermentation.

the citric acid cycle.

Which of the following best describes the main purpose of the combined processes of glycolysis and cellular respiration? breaking down ATP, so that ADP and P can be reused producing complex molecules from chemical building blocks the breakdown of glucose to carbon dioxide and water catabolism of sugars and related compounds transforming the energy in glucose and related molecules in a chemical form that cells can use for work

transforming the energy in glucose and related molecules in a chemical form that cells can use for work

In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis? none, because all of the available energy remains in either lactate or ethanol four ATP two ATP up to 30 ATP none, because in the absence of oxygen, no ATP can be made

two ATP

The electrons stripped from glucose in cellular respiration end up in which compound? oxygen NADH carbon dioxide ATP water

water