Biology: Chapter 7 Practice Questions

What would be the ATP yield for a molecule that is catabolized to form one molecule of pyruvate in a eukaryotic cell? A. 10 ATP B. 12.5 ATP C. 25 ATP D. 30 ATP E. 32 ATP

12.5 ATP

What is the net number of ATP generated directly during glycolysis per molecule of glucose? A. 0 B. 2 C. 4 D. 6 E. 8

2

What are the products of one turn of the Krebs cycle? A. 1 CO2, 2 NADH, 1 FADH2, 1 ATP B. 2 CO2, 3 NADH, 1 FADH2, 1 ATP C. 2 CO2, 6 NADH, 2 FADH2, 2 ATP D. 4 CO2, 6 NADH, 2 FADH2, 2 ATP E. 4 CO2, 12 NADH, 4 FADH2, 4 ATP

2 CO2, 3 NADH, 1 FADH2, 1 ATP

If you take into account the amount of ATP generated by ATP synthase per molecule of NADH produced in aerobic respiration, the net number of ATP molecules produced by substrate-level phosphorylation, and the fact that NADH molecules produced in the cytoplasm have to be transported into the mitochondria, what is the predicted energy yield of glycolysis in eukaryotic cells? A. 2 ATP B. 5 ATP C. 7 ATP D. 32 ATP E. 30 ATP

5 ATP

When substrate-level phosphorylation occurs, it means that: A. NAD+ is converted into NADH. B. ATP is converted into ADP plus a phosphate group. C. ADP is converted into ATP by the addition of a phosphate group. D. NADH is converted into NAD+ plus a proton.

ADP is converted into ATP by the addition of a phosphate group.

Many of the antiviral drugs currently used to treat HIV/AIDS also interfere with an enzyme that helps mitochondria multiply. Treatment can therefore result in a decrease in the number of mitochondria found in certain tissues. Given this information, what might you expect to see in patients treated with antiviral drugs? A. An increase in oxidative phosphorylation B. An increase in phosphofructokinase activity C. An increase in NADH dehydrogenase activity D. An increase in lactic acid levels

An increase in lactic acid levels

One way to generate acetyl-CoA is to convert pyruvate into acetyl-CoA by stripping off a C02 molecule. The removal of CO2 is referred to as what type of reaction? A. Decarboxylation B. Glycolytic C. Carboxylation D. Acetylation

Decarboxylation

To form NADH from NAD+, two electrons and a proton are removed from an organic molecule. What term best describes the reaction in which electrons and a proton are removed from an organic molecule? A. Condensation B. Reduction C. Dehydrogenation D. Decarboxylation E. Isomerization

Dehydrogenation

The equation for cellular respiration is: C6H12O6 + 6O2 6CO2 + 6H2O. At what specific point in the cellular respiration process has glucose been broken down completely from a six carbon molecule to 6 molecules of CO2? A. During the priming reactions in glycolysis B. During the oxidation and ATP formation reactions in glycolysis C. During pyruvate oxidation D. During the condensation reaction in the Krebs cycle E. During the second oxidation in the Krebs cycle

During the second oxidation in the Krebs cycle

During what step of glycolysis are two ATP molecules required? A. Cleavage and rearrangement B. Glucose priming C. Oxidation D. Pyruvate formation E. Acetyl-CoA formation

Glucose priming

This process is common to all living cells: A. Glycolysis B. Alcohol fermentation C. The Krebs cycle D. Electron transport chain reactions E. Pyruvate oxidation

Glycolysis

What aspect of cellular respiration occurs in the cytoplasm in eukaryotic cells? A. Glycolysis B. Pyruvate oxidation C. The Krebs cycle D. The electron transport chain E. ATP synthesis

Glycolysis

What stage of cellular respiration can occur in human cells with or without oxygen present? A. The Krebs cycle B. Glycolysis C. The electron transport chain D. Pyruvate oxidation

Glycolysis

When oxygen is unavailable during heavy exercise what process do muscle cells use for energy generation? A. Glycolysis coupled with alcohol fermentation B. Anaerobic respiration C. Aerobic respiration D. Glycolysis coupled with lactate fermentation

Glycolysis coupled with lactate fermentation

Organisms that depend on the energy stored in chemical bonds by other organisms for their food energy are called ____________. A. Autotrophs B. Heterotrophs C. Oligotrophs D. Chemotrophs

Heterotrophs

You decide to go on vacation in the mountains, where you are staying in a cabin. Unfortunately, when you turn on the water in the cabin you smell hydrogen sulfide (H2S) gas. After some research, you find out that the H2S may be due to the presence of sulfur bacteria living in your pipes. What molecule do these bacteria use as an electron acceptor? A. O2 B. H20 C. SO4 D. H2S

SO4

If ATP synthase had a mutation in the F1 complex portion of the protein, what function of ATP synthase would most likely be affected? A. The rotation of the rotor. B. The flow of protons through the channel. C. The conversion of ADP and Pi to ATP. D. The insertion of the enzyme into the membrane.

The conversion of ADP and Pi to ATP

Cytochromes contain a heme group similar to that in hemoglobin. The iron atom (Fe) in the center of the group can be oxidized and reduced. If someone was suffering from iron deficiency anemia, what stage of cellular respiration would be most affected? A. Glycolysis B. The Krebs cycle C. The electron transport chain D. Fermentation

The electron transport chain

As electrons move along the electron transport chain, they lose potential energy. How is the energy that is released used by the cell? A. The energy is used to transport protons against their concentration gradient B. The energy is used to pump electrons along the electron transport chain C. The energy is converted directly into ATP D. The energy is used to pump NAD+ into the cytoplasm so it can be used in glycolysis

The energy is used to transport protons against their concentration gradient

All of the reactions of cellular respiration that occur after glycolysis take place in what part of the eukaryotic cell? A. The chloroplast B. The nucleus C. The mitochondria D. The plasma membrane E. The cytoplasm

The mitochondria

Arsenic poisoning can lead to organ failure and death. Though arsenic can inhibit or interfere with a number of cellular enzymes, arsenic poisoning is thought to be mainly due to indirect inhibition of enzymes involved in both pyruvate oxidation and the Krebs cycle. As a result, this compound must be able to enter what cellular compartment? A. The cytoplasm B. The nucleus C. The intermembrane space of the mitochondria D. The mitochondrial matrix E. The endoplasmic reticulum

The mitochondrial matrix

What is common to all of the oxidation reactions in the Krebs cycle? A. They all lead to the generation of NADH. B. They are all decarboxylation reactions. C. They are all characterized by a loss of electrons from an organic molecule coupled to the reduction of an electron acceptor. D. They all lead to substrate-level phosphorylation of ADP to generate ATP.

They are all characterized by a loss of electrons from an organic molecule coupled to the reduction of an electron acceptor.

What must happen to amino acids before they can be used in catabolic reactions? A. They must be decarboxylated B. They must be deoxygenated C. They must be dehydrogenated D. They must be deaminated

They must be deaminated

In the absence of oxygen, can cells utilize the electron transport chain? A. Yes, all cells can make use of the electron transport chain in the absence of oxygen via fermentation. B. No, oxygen is a required cofactor for the complexes in the electron transport chain. C. Yes, in the case that a cell can use a terminal electron acceptor other than oxygen, it can make use of the electron transport chain. D. No, oxygen is the primary electron acceptor in electron transport chains in all cell types.

Yes, in the case that a cell can use a terminal electron acceptor other than oxygen, it can make use of the electron transport chain.

Organisms that can manufacture their own chemical energy are called ____________. A. autotrophs B. heterotrophs C. oligotrophs D. chemotrophs

autotrophs

How and where is ATP made in a eukaryotic cell? A. ATP is only made in the mitochondria in response to chemiosmosis. B. ATP is made in all compartments of the cell in response to endergonic reactions and is used to drive exergonic reactions in the cell. C. ATP can be made by direct phosphorylation of ADP in the cytoplasm, and by an enzyme complex that uses the energy from a proton gradient to drive ATP synthesis in the mitochondria. It can also be made in other locations in the cell, depending on the cell type. D. ATP can be made by an enzyme complex that uses the energy of protons moving down their concentration gradient from the mitochondrial matrix to the cytoplasm to make the ATP.

ATP can be made by direct phosphorylation of ADP in the cytoplasm, and by an enzyme complex that uses the energy from a proton gradient to drive ATP synthesis in the mitochondria. It can also be made in other locations in the cell, depending on the cell type.

Why is the energy generated from the catabolism of sugars and other macromolecules ultimately harnessed to generate ATP? A. ATP can be used by cells to drive endergonic reactions B. ATP can be used to make RNA, which is an energy storage molecule in the cell C. ATP synthesis is an exergonic reaction D. ATP is required to generate the proton gradient in the intermembrane space of mitochondria

ATP can be used by cells to drive endergonic reactions

Glucose is not our only food source, nor the only one we can utilize in our bodies to generate energy. Other primary sources of energy include other sugars, proteins, and fats. What metabolic intermediate are fats primarily converted into? A. Pyruvate B. Acetyl-CoA C. Krebs cycle intermediates D. Electron transport chain components E. ATP Synthase

Acetyl-CoA

In animals that take in oxygen from their environment, glucose is broken down into carbon dioxide and water in a process called: A. Anaerobic respiration B. Organic compound respiration C. Glucose respiration D. Aerobic respiration

Aerobic respiration

Phosphofructokinase is regulated by a number of factors, including high levels of ATP. Why is this enzyme regulated by ATP levels? A. If ATP levels are high, this provides a mechanism to directly inhibit the Krebs cycle, thus preventing further generation of NADH, FADH2 and ATP molecules that are not needed. B. If ATP levels are high, it is important to directly inhibit the reaction that commits the substrate to glycolysis to allow the substrate to be available for other reactions, since the cell has ample energy. C. If ATP levels are high, it is important to inhibit ATP synthase, and phosphofructokinase directly inhibits ATP synthase. D. If ATP levels are high, this provides a mechanism to directly inhibit the electron transport chain, thus preventing the formation of a proton gradient in the intermembrane space of mitochondria.

If ATP levels are high, it is important to directly inhibit the reaction that commits the substrate to glycolysis to allow the substrate to be available for other reactions, since the cell has ample energy.

Where does pyruvate oxidation occur in eukaryotic cells? A. In the cytoplasm B. In the nucleus C. In the Golgi body D. In the mitochondria E. In the plasma membrane

In the mitochondria

The energy released in the mitochondrial electron transport chain is used to transport protons where? A. Into the mitochondrial matrix B. Into the cytoplasm C. Into the endoplasmic reticulum D. Into the intermembrane space of the mitochondria E. Into the nucleus

Into the intermembrane space of the mitochondria

What happens to the oxygen that is used in cellular respiration? A. It is converted to carbon dioxide B. It is used to make glucose C. It is used to make Krebs cycle intermediates D. It is reduced to form water E. It is converted to acetyl-CoA

It is reduced to form water

Regardless of the electron or hydrogen acceptor used, one of the products of fermentation is always: A. ADP B. ATP C. NAD+ D. pyruvate E. alcohol

NAD+

What oxidizing agent is used to temporarily store high energy electrons harvested from glucose molecules in a series of gradual steps in the cytoplasm? A. FADH2 B. ADP C. NAD+ D. Oxygen

NAD+

What is different about the way that NADH and FADH2 donate electrons to the electron transport chain? A. NADH is oxidized and FADH2 is reduced. B. NADH contributes its electrons to the first transmembrane complex in the electron transport chain and FADH2 contributes its electrons after the first transmembrane complex. C. More protons are transported into the intermembrane space of the mitochondria in response to one molecule of FADH2 as compared to the number of protons transported in response to one molecule of NADH. D. The electrons from NADH ultimately go on to reduce oxygen to generate water, whereas the electrons from FADH2 are used to reduce pyruvate to lactate.

NADH contributes its electrons to the first transmembrane complex in the electron transport chain and FADH2 contributes its electrons after the first transmembrane complex.

In glycolysis, a major portion of the energy remains in the final product, which is called: A. Glucose B. Citrate C. Glyceraldehyde 3-phosphate (G3P) D. Pyruvate

Pyruvate

What is an end-product of glycolysis? A. Oxaloacetate B. NAD+ C. Alcohol D. ADP E. Pyruvate

Pyruvate

When amino acids are degraded in cells, into what intermediate(s) of the aerobic respiration process are the carbon skeletons of amino acids primarily converted? A. Pyruvate B. Acetyl-CoA C. Krebs cycle intermediates D. Pyruvate and acetyl-CoA E. Pyruvate and Krebs cycle intermediates

Pyruvate and Krebs cycle intermediates

In aerobic respiration, chemiosmotic generation of ATP is driven by: A. Pi transfer through the plasma membrane. B. the Na+/K+ pump. C. a difference in H+ concentration on the two sides of the inner mitochondrial membrane. D. osmosis of macromolecules. E. large quantities of ADP.

a difference in H+ concentration on the two sides of the inner mitochondrial membrane.