Chapter 7 Mastering Biology

Gaseous hydrogen burns in the presence of oxygen to form water:2H2 + O2 → 2H2 O + energy. Which molecule is oxidized and what kind of bond is formed? a.Hydrogen, polar. b.Oxygen, polar. c.Hydrogen, nonpolar. d.Oxygen, nonpolar.

a

Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration? a.Carbon dioxide b.NADH c.ATP d.Water

a

True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups. a.True b.False

a

What molecules belong in spaces E and F? a. carbon dioxide and water b.glucose, water, carbon dioxide, and oxygen c.glucose and oxygen d.carbon dioxide and oxygen d.oxygen and water

a

What process occurs in Box A? a.glycolysis b.oxidative phosphorylation c.electron transport and oxidative phosphorylation d.electron transport e.the citric acid cycle

a

__________- is the compound that functions as the electron acceptor in glycolysis.

NAD+

Which of the following statements is not true of most cellular redox reactions? a. A hydrogen atom is transferred to the atom that loses an electron. b.The reactant that is oxidized loses electrons. c.The electron acceptor is reduced. d.Changes in potential energy can be released as heat.

a

The reduced form of the electron acceptor in glycolysis is ____-

NADH

During electron transport, energy from _____ is used to pump hydrogen ions into the _____.

NADH and FADH2 ... intermembrane space

-------- donates electrons to the electron transport chain.

NADH donates electrons to the electron transport chain.

What is the correct order of electron transport compounds from best electron donor to best electron acceptor? O2 -- Fe-S of Complex I -- NADH -- Q -- Fe-S of Complex III -- Cyt c-- Cyt a of Complex IV b. NADH -- Fe-S of Complex I -- Q -- Fe-S of Complex III -- Cyt c-- Cyt a of Complex IV -- O2 c.O2 -- Cyt a of Complex IV -- Cyt c -- Fe-S of Complex III -- Q -- Fe-S of Complex I -- NADH d.NADH -- Cyt c -- Fe-S of Complex I -- Q -- Fe-S of Complex III -- Cyt a of Complex IV-- O2

V

Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other? Proton and electron .Ionic and covalent. Anion and cation. Polar and nonpolar.

anion and cation

structure a is

atp synthase

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

b

In the process of cellular respiration, what is consumed, and what is produced? View Available Hint(s) a. Carbon dioxide is consumed, and water is produced. b.Glucose is consumed, and carbon dioxide is produced. c.Oxygen is consumed, and glucose is produced. d.ATP is consumed, and oxygen is produced. e.Water is consumed, and ATP is produced.

b

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

b

What kind of bond is formed when lithium and fluorine combine to form lithium fluoride? a.Polar covalent. b.Ionic. c.Redox. d.Nonpolar covalent.

b

Which of the following is the most important result of the process of cellular respiration in biological systems? a. catabolism of sugars and related compounds b.transforming the energy in glucose and related molecules in a chemical form that cells can use for work c.producing complex molecules from chemical building blocks d, breaking down ATP so that ADP and Pi can be reused e.the breakdown of glucose to carbon dioxide and water

b

Which of the following statements about the electron transport chain is true? a. Water is the last electron acceptor. b.NADH and FADH2 donate their electrons to the chain. c.The electron transport chain is the first step in cellular respiration. d.Electrons gain energy as they move down the chain.

b

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

d

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

d

What molecules belong in space A and B? a. glucose and carbon dioxide b.carbon dioxide and oxygen c. oxygen and water d.carbon dioxide and water e.glucose and oxygen

e

What process occurs in Box b? a.glycolysis b.oxidative phosphorylation c.electron transport and oxidative phosphorylation d.electron transport e.the citric acid cycle

e

What process occurs in structure H? a. ribosome synthesis b. intracellular digestion c. cellular respiration d. protein synthesis e. photosynthesis

e

Which term describes the degree to which an element attracts electrons? Oxidation. Electronegativity. Reduction. Polarity.

electronegativity

In glycolysis, the carbon-containing compound that functions as the electron donor is __________.

glucose

Considering the role of coenzyme Q, how do you think this product might function as a nutritional supplement to benefit the heart?

CoQ is necessary for the cellular respiration and energy production, and thus it can improve the heart work providing this organ with energy. As a result, CoQ as a nutritional supplement may contribute to more stable heartbeat.

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?

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

How will a healthy individual's ATP production change during an eight-hour fast?

The individual's ATP production will not change significantly.

Part complete In mitochondria, exergonic redox reactions __________.

provide the energy that establishes the proton gradient

Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called __________

pyruvate

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

pyruvate

In fermentation _____ is reduced and _____ is oxidized.

pyruvate ... NADH

Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions?

pyruvate, ATP, NADH

When a compound accepts (gains) electrons, that compound becomes ___________. Such a compound is often referred to as an electron acceptor.

reduced

When the protein gramicidin is integrated into a membrane, an H+ channel forms and the membrane becomes very permeable to protons (H+ ions). If gramicidin is added to an actively respiring muscle cell, how would it affect the rates of electron transport, proton pumping, and ATP synthesis in oxidative phosphorylation? (Assume that gramicidin does not affect the production of NADH and FADH2 during the early stages of cellular respiration.) Sort the labels into the correct bin according to the effect that gramicidin would have on each process.

remains the same: proton pumping rate electron transport rate rate of oxygen uptake decreases (or goes to zero) rate of ATP synthesis size of the proton gradient

For each glucose that enters glycolysis, _____ acetyl CoA enter the citric acid cycle.

2

In muscle cells, fermentation produces _____.

lactate and NAD+

In the citric acid cycle, ATP molecules are produced by _____.

subtrate level phosphorlation

It suggests that the organelles, mitochondria and chloroplasts, arose from a(n) 1 relationship with 2 early in evolutionary time. If the ATP synthases arose independently for each cases, i.e., through 3 evolution, you would expect very 4 amino acid sequences.

1. endosymboitc 2,bacteria 3.convergent 4different

In glycolysis, PFK transfers a phosphate group from A T P to 1. It is an allosteric enzyme 2 by high concentrations of 3 and stimulated by higher concentrations of 4. Thus glycolysis is stimulated when energy charge 5 .

1. the sugar 2. inhibited 3. ATP 4. AMP 5. falls

H+H+ would 1 pumped across the membrane into the 2 and H+ would 3 to flow back through ATPA synthase since the enzyme is inhibited by the poison. Therefore, pH difference across the membrane would increase.

1.continue to be 2.intermembrane space 3.not be able

In glycolysis there is a net gain of how many ATP

2

n the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?

2

For each glucose that enters glycolysis, _____ NADH + H+ are produced by the citric acid cycle.

6

Approximately how much more free energy is supplied to the electron transport chain by NADH than by FADH2?

8

In mitochondrial electron transport, what is the direct role of O2? A. to function as the final electron acceptor in the electron transport chain B.to oxidize NADH and FADH2 from glycolysis, acetyl CoA formation, and the citric acid cycle C.to provide the driving force for the production of a proton gradient D.to provide the driving force for the synthesis of ATP from ADP and Pi

A

How many NADH are produced by glycolysis? A.5 B.2 C.1 D.3 E.4

B

In glycolysis, ATP molecules are produced by _____. A. cellular respiration B. substrate-level phosphorylation C. oxidative phosphorylation D.photosynthesis E.photophosphorylation

B

What molecule is indicated by the letter D? A.water B.oxygen C.ATP D.glucose E.pyruvate

B

___ is a prosthetic group present in several components of the electron transport chain.

Fe-S

How would anaerobic conditions (when no O2 is present) affect the rate of electron transport and ATP production during oxidative phosphorylation? (Note that you should not consider the effect on ATP synthesis in glycolysis or the citric acid cycle.) A. Electron transport would be unaffected but ATP synthesis would stop. B.Electron transport would stop but ATP synthesis would be unaffected. C.Both electron transport and ATP synthesis would stop. D.Neither electron transport nor ATP synthesis would be affected.

C

___________-is a multi-protein complex within the electron transport chain

Complex III is a multi-protein complex within the electron transport chain

NADH and FADH2 are both electron carriers that donate their electrons to the electron transport chain. The electrons ultimately reduce O2 to water in the final step of electron transport. However, the amount of ATP made by electrons from an NADH molecule is greater than the amount made by electrons from an FADH2 molecule. Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH2? A.There is more NADH than FADH2 made for every glucose that enters cellular respiration. B.It takes more energy to make ATP from ADP and Pi using FADH2 than using NADH. C.FADH2 is made only in the citric acid cycle while NADH is made in glycolysis, acetyl CoA formation, and the citric acid cycle. D.Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor. E. The H+ gradient made from electron transport using NADH is located in a different part of the mitochondrion than the H+ gradient made using FADH2.

D

Of the following lists of electron transport compounds, which one lists them in order from the one containing electrons with the highest free energy to the one containing electrons with the lowest free energy? Note that not all electron transport compounds in the electron transport chain are listed. A. FMN of Complex I -- NADH -- Fe-S of Complex III -- Cyt b of Complex III -- Cyt c -- Cyt a of Complex IV -- O2 B. O2 -- Cyt a of Complex IV -- Cyt c -- Fe-S of Complex III -- Q -- Fe-S of Complex II -- FADH2 C.FADH2 -- Fe-S of Complex II -- Fe-S of Complex III -- Q -- Cyt a of Complex IV -- Cyt c -- O2 D. FADH2 -- Fe-S of Complex II -- Q -- Fe-S of Complex III -- Cyt c -- Cyt a of Complex IV -- O2

D

Which of these is NOT a product of glycolysis? A.ATP B.NADH C.pyruvate D.FADH2

D

In glycolysis, what starts the process of glucose oxidation? A. FADH2 B.ADP C. NAD D. PHhexokinase E,ATP

E

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the __________. fl

H+ concentration gradient across the membrane holding ATP synthase

The by-product of anaerobic respiration of some bacteria is __________.

H2S

In the last stage of cellular respiration, oxidative phosphorylation, all of the reduced electron carriers produced in the previous stages are oxidized by oxygen via the electron transport chain. The energy from this oxidation is stored in a form that is used by most other energy-requiring reactions in cells. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of oxidative phosphorylation. Drag each compound to the appropriate bin. If a compound is not involved in oxidative phosphorylation, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of oxidative phosphorylation are listed.)

Input: NADH O2 ADP Output: water ATP NAD+

Part complete 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

From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of glycolysis. Drag each compound to the appropriate bin. If the compound is not involved in glycolysis, drag it to the "not input or output" bin.

Net Input: glucose NAD+ ADP Output: pyruvate ATP NADH

Is CoQ used as a "fuel" during cellular respiration?

No, CoQ is a member of the electron transport chain and thus can't be metabolized as an energy molecule

__________ is the final electron acceptor of the electron transport chain.

O2 (molecular oxygen) is the final electron acceptor of the electron transport chain.

________- is a nonprotein organic electron carrier within the electron transport chain.

Q (ubiquinone)

When electrons flow along the electron transport chains of mitochondria, which of the following changes does not occur?

The electrons gain free energy.

Which of the following statements is true of the bonds in a water molecule? a. There is equal sharing of the electrons between the oxygen atom and the two hydrogen atoms, and the net charge is zero. b.Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero. c.The electron in each hydrogen atom is completely transferred to the oxygen atom, and each hydrogen atom has a net charge of +1. d.Oxygen acts as the electron acceptor and is oxidized.

b

Which step of the cellular respiration pathway can take place in the absence of oxygen? a.Fermentation b.Glycolysis c.Electron transport chain d.Krebs cycle

b

If a mitochondrion ran out of molecular oxygen (O2), predict which of the following situations would occur in its electron transport chain. a. Electrons would start to flow in the opposite direction, converting water into O2 and H+. b.H2O would be made instead of O2 at the end of the chain. c,FMN prosthetic groups would remain reduced and NADH would have nowhere to donate electrons. d.FADH2 would be the main electron donor to the electron transport chain instead of NADH. e.Cyt a 3 prosthetic groups would remain oxidized and Cyt a would have nowhere to donate electrons.

c

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? a.The advantage of an electron transport chain is the production of a large number of reduced, high-energy intermediates. b.The advantage of the respiratory electron transport chain is that oxygen is the final electron acceptor. c.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.

c

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

c

What organelle is indicated by the letter C? a.lysosome b.peroxisome c.mitochondrion d.chloroplast e.Golgi apparatus

c

Which molecule is metabolized in a cell to produce energy "currency" in the form of ATP? a. Carbon dioxide b.Phosphate c.Glucose d.ADP

c

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

c

Which of these enters the citric acid cycle? G3P b.pyruvate c,acetyl CoA d.glucose e,NADH + H+

c

Which of these is NOT a product of the citric acid cycle? a.NADH + H+ b.ATP c.acetyl CoA d.CO2 e.FADH2

c

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

c

Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell? a.Glycolysis b.Krebs cycle c.Fermentation d.Electron transport chain

c

Which stage of glucose metabolism produces the most ATP? a. Fermentation of pyruvate to lactate b. Krebs cycle c.Electron transport and chemiosmosis d.Glycolysis

c

Most CO2 from catabolism is released during _______

citric acid cycle

The ATP that is generated in glycolysis is produced by substrate-level phosphorylation, a very different mechanism than the one used to produce ATP during oxidative phosphorylation. Phosphorylation reactions involve the addition of a phosphate group to another molecule. Sort the statements into the appropriate bin depending on whether or not they correctly describe some aspect of substrate-level phosphorylation in glycolysis. One of the substrates is a molecule derived from the breakdown of glucose. An enzyme is required in order for the reaction to occur. A bond must be broken between an organic molecule and phosphate before ATP can form. The enzymes involved in ATP synthesis must be attached to a membrane to produce ATP. The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions.

correct statements One of the substrates is a molecule derived from the breakdown of glucose. An enzyme is required in order for the reaction to occur. A bond must be broken between an organic molecule and phosphate before ATP can form. incorrect statements The enzymes involved in ATP synthesis must be attached to a membrane to produce ATP. The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions.

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?

glycolysis

Each of the four stages of cellular respiration occurs in a specific location inside or outside the mitochondria. These locations permit precise regulation and partitioning of cellular resources to optimize the utilization of cellular energy. Match each stage of cellular respiration with the cellular location in which it occurs. Labels may be used once, more than once, or not at all.

glycolysis-ctyosol acetyl CoA formation- mitochondrial matrix citric acid cycle-mitochondrial matrix oxidative phosphorlation- inner mitochondrial membrane

In the citric acid cycle (also known as the Krebs cycle), acetyl CoA is completely oxidized. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of the citric acid cycle. Drag each compound to the appropriate bin. If a compound is not involved in the citric acid cycle, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of the citric acid cycle are included.)

input: NAD+ ADP acetyl CoA output: CO2 NADH ATP Coenzyme A

The proximate (immediate) source of energy for oxidative phosphorylation is _____.

kinetic energy that is released as hydrogen ions diffuse down their concentration gradient

In acetyl CoA formation, the carbon-containing compound from glycolysis is oxidized to produce acetyl CoA. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of acetyl CoA formation. Drag each compound to the appropriate bin. If a compound is not involved in acetyl CoA formation, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of acetyl CoA formation are included.)

net input NAD+ Pyruvate Coenzyme A output acetyl CoA NADH CO2

In cellular respiration, most ATP molecules are produced by _____.

oxidative phosphorylation

When a compound donates (loses) electrons, that compound becomes _________-. Such a compound is often referred to as an electron donor.

oxidized

The final electron acceptor of cellular respiration is _____.

oxygen

True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria. a.True b. False

true

The electrons stripped from glucose in cellular respiration end up in which compound?

water