Mastering Biology: Chapter 9

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

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

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

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

Most CO2 from catabolism is released during

Select the correct statement about cellular respiration.

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

Which of the following statements accurately describes the function of a metabolic pathway involved in cellular respiration?

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?

Identify all correct statements about the basic function of fermentation. Select all that apply.

Which of the following cheeses would likely spoil the most quickly?

You create a new variety of cheese that has very little water. Which of the following is true?

You are a cheese maker wanting to connect a large quantity of lactose to acid. Which of the following do you need?

Successfully making cheese requires separating what?

Which of the following is true?

Based on the graph, is PFK more active at low or high ATP concentration?

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?

In mitochondria, exergonic redox reactions

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is

What process occurs in structure H?

What molecules belong in space A and B?

What organelle is indicated by the letter C?

What molecules belong in spaces E and F?

What process occurs in Box A?

What process occurs within Box B?

What molecule is indicated by the letter D?

Which term describes the degree to which an element attracts electrons?

Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?

Which of the following statements is true of the bonds in a water molecule?

Which of the following statements is not true of most cellular redox reactions?

What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?

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?

Which of the following best describes the main purpose of the combined processes of glycolysis and cellular respiration?

In the combined processes of glycolysis and cellular respiration, what is consumed and what is produced?

Substrate-level phosphorylation occurs _____.

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction _____.

When electrons move closer to a more electronegative atom, what happens? The more electronegative atom is _____.

Which of the listed statements describes the results of the following reaction? C6H12O6 + 6 O2 ? 6 CO2 + 6 H2O + Energy

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

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

Which of the following statements about NAD+ is true?

The oxygen consumed during cellular respiration is involved directly in which process or event?

Carbohydrates and fats are considered high-energy foods because they _____.

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?

In glycolysis, as in all the stages of cellular respiration, the transfer of electrons from electron donors to electron acceptors plays a critical role in the overall conversion of the energy in foods to energy in ATP. These reactions involving electron transfers are known as oxidation-reduction, or redox, reactions. Drag the words on the left to the appropriate blanks on the right to complete the sentences.

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

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.

How many NADH are produced by glycolysis?

In glycolysis, ATP molecules are produced by _____.

Which of these is NOT a product of glycolysis?

In glycolysis, what starts the process of glucose oxidation?

In glycolysis there is a net gain of _____ ATP.

Which of the following describes the process of glycolysis?

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?

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?

Starting with one molecule of glucose, the energy-containing products of glycolysis are _____.

In glycolysis, for each molecule of glucose oxidized to pyruvate _____.

Which kind of metabolic poison would most directly interfere with glycolysis?

During acetyl CoA formation and the citric acid cycle, all of the carbon atoms that enter cellular respiration in the glucose molecule are released in the form of CO2. Use this diagram to track the carbon-containing compounds that play a role in these two stages. Drag the labels from the left (which represent numbers of carbon atoms) onto the diagram to identify the number of carbon atoms in each intermediate in acetyl CoA formation and the citric acid cycle. Labels may be used more than once.

In the sequential reactions of acetyl CoA formation and the citric acid cycle, pyruvate (the output from glycolysis) is completely oxidized, and the electrons produced from this oxidation are passed on to two types of electron acceptors. Drag the labels on the left to show the net redox reaction in acetyl CoA formation and the citric acid cycle. Note that two types of electron carriers are involved.

In the oxidation of pyruvate to acetyl CoA, one carbon atom is released as CO2. However, the oxidation of the remaining two carbon atoms—in acetate—to CO2 requires a complex, eight-step pathway—the citric acid cycle. Consider four possible explanations for why the last two carbons in acetate are converted to CO2 in a complex cyclic pathway rather than through a simple, linear reaction. Use your knowledge of the first three stages of cellular respiration to determine which explanation is correct.

Which of these enters the citric acid cycle?

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

Which of these is NOT a product of the citric acid cycle?

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?

Which statement about the citric acid cycle is correct?

Most of the CO2 from the catabolism of glucose is released during _____.

Following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of _____.

Which electron carrier(s) function in the citric acid cycle?

If you were to add one of the eight citric acid cycle intermediates to the culture medium of yeast growing in the laboratory, what do you think would happen to the rates of ATP and carbon dioxide production?

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

If glucose is the sole energy source, what fraction of the carbon dioxide exhaled by animals is generated by the reactions of the citric acid cycle?

For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see the accompanying figure)?

If pyruvate oxidation is blocked, what will happen to the levels of oxaloacetate and citric acid in the citric acid cycle shown in the accompanying figure?

Starting with citrate, which of the following combinations of products would result from three acetyl CoA molecules entering the citric acid cycle (see the accompanying figure)?

Use the following information to answer the questions below. In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate (1) loses a carbon, which is given off as a molecule of CO2, (2) is oxidized to form a two-carbon compound called acetate, and (3) is bonded to coenzyme A. The three listed steps result in the formation of _____.

Which one of the following is formed by the removal of a carbon (as CO2) from a molecule of pyruvate?

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.

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.)

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.)

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.)

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.

In mitochondrial electron transport, what is the direct role of O2?

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.)

Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH2?

Sort the labels into the correct bin according to the effect that gramicidin would have on each process.

The four stages of cellular respiration do not function independently. Instead, they are coupled together because one or more outputs from one stage functions as an input to another stage. The coupling works in both directions, as indicated by the arrows in the diagram below. In this activity, you will identify the compounds that couple the stages of cellular respiration. Drag the labels on the left onto the diagram to identify the compounds that couple each stage. Labels may be used once, more than once, or not at all.

Which of these statements is the correct explanation for this observation?

The rate of cellular respiration is regulated by its major product, ATP, via feedback inhibition. As the diagram shows, high levels of ATP inhibit phosphofructokinase (PFK), an early enzyme in glycolysis. As a result, the rate of cellular respiration, and thus ATP production, decreases. Feedback inhibition enables cells to adjust their rate of cellular respiration to match their demand for ATP. Which statement correctly describes how this increased demand would lead to an increased rate of ATP production?

What would happen to the cell's rate of glucose utilization?

Which molecule is metabolized in a cell to produce energy for performing work?

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

Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?

Which step of the cellular respiration pathway can take place in the absence of oxygen?

Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?

Which of the following statements about the electron transport chain is true?

Which stage of glucose metabolism produces the most ATP?

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

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

Which of the following statements about the chemiosmotic synthesis of ATP is correct?

Which one of the following statements about the redox reactions of the electron transport chain is correct?

To see patterns in the data from an experiment like this, it is helpful to graph the data. A bar graph is used instead of a line graph because each type of liver cell was independent of the others. But first, you must determine which variable should go on each axis of the graph. What variable did the researchers intentionally vary in the experiment, and what are the units for this variable?

What variable responded to thyroid hormone level (the independent variable), and what are the units for this variable?

What variable responded to thyroid hormone level (the independent variable), and what are the units for this variable?

Now that you have determined which variable goes on each axis, the graph can be constructed. Assuming that the x-axis tick marks will be used to identify the thyroid hormone level of each type of rat, what bars should appear on the x-axis?

Assuming that the y-axis tick marks will be separated by 1.0 (0.0, 1.0, 2.0, and so on), what is the largest value that should appear on the y-axis?

Which cell type(s) had the highest rate of oxygen consumption?

Which cell type(s) had the lowest rate of oxygen consumption?

Do the results in the graph support the researchers' hypothesis?

Based on what you know about mitochondrial electron transport and heat production, predict which rats had the highest body temperature, and which had the lowest body temperature.

Which of the following events takes place in the electron transport chain?

The electron transport chain _____.

The chemiosmotic hypothesis is an important concept in our understanding of cellular metabolism in general because it explains _____.

During aerobic respiration, electrons travel downhill in which sequence?

Where are the proteins of the electron transport chain located?

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?

The primary role of oxygen in cellular respiration is to _____.

During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation of the water come from?

In chemiosmosis, what is the most direct source of energy that is used to convert ADP + i to ATP?

Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the _____.

Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration?

The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of _____.

If a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely oxidized to carbon dioxide and water, approximately how many ATP molecules can the cell synthesize for each molecule of pyruvate oxidized to carbon dioxide and water?

In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve?

You have a friend who lost 7 kg (about 15 pounds) of fat on a regimen of strict diet and exercise. How did the fat leave his body?

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. After the disruption, when electron transfer and ATP synthesis still occur, what must be present?

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 _____.

Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in _____.

Match each product of pyruvate metabolism with the condition under which it is produced.

In muscle cells, fermentation produces _____.

In fermentation _____ is reduced and _____ is oxidized.

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

Which of the following normally occurs regardless of whether or not oxygen (O2) is present?

Which of the following occurs in the cytosol of a eukaryotic cell?

In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of _____.

One function of both alcohol fermentation and lactic acid fermentation is to _____.

An organism is discovered that thrives in both the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism _____.

Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

Yeast cells that have defective mitochondria incapable of respiration will be able to grow by catabolizing which of the following carbon sources for energy?

New biosensors, applied like a temporary tattoo to the skin, can alert serious athletes that they are about to "hit the wall" and find it difficult to continue exercising. These biosensors monitor lactate, a form of lactic acid, released in sweat during strenuous exercise. Which of the statements below is the best explanation of why athletes would need to monitor lactate levels?

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?

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

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 _____.

Glycolysis is active when cellular energy levels are _____; the regulatory enzyme, phosphofructokinase, is _____ by ATP.

Canine phosphofructokinase (PFK) deficiency afflicts Springer spaniels, affecting an estimated 10% of the breed. Given its critical role in glycolysis, one implication of the genetic defect resulting in PFK deficiency in dogs is _____.

A young dog has never had much energy. He is brought to a veterinarian for help and she decides to conduct several diagnostic tests. She discovers that the dog's mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of the dog's condition?

Even though plants cells photosynthesize, they still use their mitochondria for oxidation of pyruvate. This will occur in _____.

In respiration, beta oxidation involves the _____.

Fatty acids usually have an even number of carbons in their structures. They are catabolized by a process called beta-oxidation. The end products of the metabolic pathway are acetyl groups of acetyl CoA molecules. These acetyl groups _____.

Cellular respiration requires fuel (glucose) and oxygen gas. The main process that produces these inputs is _____.

Which part(s) of cellular respiration require(s) oxygen gas?

What is/are the most important output(s) of glycolysis?

Unlike the Citric Acid cycle and electron transport, glycolysis occurs _____.

Glycolysis is the multi-step breakdown of _____. Several different _____ play a role in this process.

A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to kill bacteria in people with infections. However, he cannot do this because __________.

Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step __________.

A small amount of ATP is made in glycolysis by which of the following processes?

Drag the labels onto the diagram to identify how chemicals cycle in an ecosystem.

When a poison such as cyanide blocks the electron transport chain, glycolysis and the citric acid cycle also eventually stop working. Which of the following is the best explanation for this?

Which part(s) of cellular respiration take(s) place in the mitochondria?

What is the role of oxygen in cellular respiration?

Cellular respiration accomplishes two major processes: (1) it breaks glucose down into smaller molecules, and (2) it harvests the chemical energy released and stores it in ATP molecules. By the end of _____, the breakdown of glucose is complete; most ATP molecules are produced during _____.

NADH and FADH 2 are important in cellular respiration because they deliver high-energy electrons to the electron transport system. Electron transport produces _____ ATP molecule(s) per NADH molecule and _____ ATP molecules(s) per FADH 2 molecule.

In electron transport, high-energy electrons "fall" to oxygen through a series of reactions. The energy released is used to _____.

Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.

What is the correct general equation for cellular respiration?

Which of the following processes takes place in the cytosol of a eukaryotic cell?

In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

Which statement describes glycolysis?

Which statement describes the electron transport chain?

Which of the following molecules is broken down in cellular respiration, providing fuel for the cell?

Which energy-rich molecule produced by cellular respiration directly powers cell work?

How many molecules of ATP are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen?

A molecule becomes more oxidized when it __________.

Sports physiologists at an Olympic training center wanted to monitor athletes to determine at what point their muscles were functioning anaerobically. They could do this by checking for a buildup of which of the following compounds?

Where do the reactions of glycolysis occur in a eukaryotic cell?

Which of the following events accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle?

There is no production of carbon dioxide in glycolysis. Which of the following is the best explanation for this fact?

The function of cellular respiration is to __________.

Which of the following best describes the electron transport chain?

In the overall process of glycolysis and cellular respiration, __________ is oxidized and __________ is reduced.

In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs?

Each ATP molecule contains about 1% of the amount of chemical energy available from the complete oxidation of a single glucose molecule. Cellular respiration produces about 32 ATP from one glucose molecule. What happens to the rest of the energy in glucose?

Which of the following is a correct description of the events of cellular respiration in proper sequence?

In glycolysis in the absence of oxygen, cells need a way to regenerate which compound?

Which of the following is the process in which glucose is oxidized to generate two molecules of pyruvate, and in which ATP and NADH are produced?

Which of the following processes generates most of the NADH that delivers electrons to the electron transport chain?

Which of the following statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a 1-hour class period in a classroom of 300 students if the heating and air conditioning is turned off and all doors are kept closed?

In eukaryotic cells, the components of the electron transport chain are located in or on __________.

Oxygen gas (O2) is one of the strongest oxidizing agents known. The explanation for this is that __________.