Biology Test 2 Part 2

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Chapter 7

Cells release energy from molecules such as glucose in a process very similar to inhalation of air and exhalation of carbon dioxide by humans. This process is
known as cellular
a. oxidation.
b. reduction.
c. photosynthesis.
d. radiation.
e. respiration.

e. respiration.

Cytochromes are respiratory proteins. Which of the following statements accurately reflects their true nature? (1 point)
a. Cytochrome proteins reside free in the lung cells of all vertebrates. These molecules contain a heme group with an iron atom at its center.
b. Cytochrome proteins reside in the mitochondria and are specifically associated with the electron transport system.
c. Cytochrome proteins reside in the mitochondria and are specifically associated with the Kreb cycle.
d. Cytochrome proteins reside in the mitochondria and are specifically associated with glycolysis.

b. Cytochrome proteins reside in the mitochondria and are specifically associated with the electron transport system.

The Krebs cycle occurs in the mitochondria. There are nine biochemical reactions involved in the Krebs cycle, and they are highly ordered. Select the correct order from the following choices. (Note: These are abbreviated and do not show NAD, ADP, ATP, or FAD.) (1 point)
a. acetyl-CoA joins the Kreb cycle and unites with oxaloacetate → forming citrate → which forms beta-ketoglutarate → which forms succinylCoA → which forms succinate → which forms fumarate → which forms malate → which forms oxaloacetate
b. acetyl-CoA joins the Kreb cycle and unites with oxaloacetate → forming citrate → which forms alpha-ketoglutarate → which forms succinylCoA → which forms succinate → which forms malate → which forms fumarate → which forms oxaloacetate
c. acetyl-CoA joins the Kreb cycle and unites with oxaloacetate → which forms alpha-ketoglutarate → forming citrate → which forms succinylCoA → which forms succinate → which forms fumarate → which forms malate → which forms oxaloacetate
d. acetyl-CoA joins the Kreb cycle and unites with oxaloacetate → forming citrate → which forms alpha-ketoglutarate → which forms succinylCoA → which forms succinate → which forms fumarate → which forms malate → which forms oxaloacetate

d. acetyl-CoA joins the Kreb cycle and unites with oxaloacetate → forming citrate → which forms alpha-ketoglutarate → which forms succinylCoA → which forms succinate → which forms fumarate → which forms malate → which forms oxaloacetate

When ATP levels are high, oxidative pathways are inhibited, so acetyl-CoA is channeled into (1 point)
a. fatty acid synthesis.
b. pyruvate formation.
c. the Krebs cycle.
d. the electron transport system.
e. NAD production.

a. fatty acid synthesis.

When substrate-level phosphorylation occurs, it means that
(1 point)
a. NAD is converted into NADH.
b. ATP is converted into ADP + a phosphate group.
c. ADP is converted into ATP by addition of a phosphate group.
d. cAMP is converted into ADP by adding a phosphate group.
e. NADH is converted into NAD + H.

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

Which of the following statements accurately reflects the process of glycolysis?
(1 point)
a. Glycolysis is most likely one of the earliest of all biochemical reactions to evolve. Glycolysis uses molecular oxygen, however it occurs in anaerobic environments.
b. Glycolysis is most likely one of the earliest of all biochemical reactions to evolve. Glycolysis uses no molecular oxygen. All reactions of glycolysis occur free in the cytoplasm.
c. Glycolysis is most likely one of the earliest of all biochemical reactions to evolve. Glycolysis uses molecular oxygen, however it occurs in aerobic environments.
d. Glycolysis is most likely one of the earliest of all biochemical reactions to evolve. Glycolysis uses molecular oxygen and occurs in the mitochondria.

b. Glycolysis is most likely one of the earliest of all biochemical reactions to evolve. Glycolysis uses no molecular oxygen. All reactions of glycolysis occur free in the cytoplasm.

Which of the following statements accurately reflects what happens to a glucose molecule during the initial five phases of glycolysis? (1 point)
a. Glucose, a six-carbon sugar, enters the cell by passive transport and is primed and converted into glucose three-phosphate, which requires two ATP molecules. The remaining four steps involve splitting the six-carbon molecule into two three-carbon molecules.
b. Glucose, a six-carbon sugar, enters the cell by active transport and is primed and converted into glucose three-phosphate, which requires two ATP molecules. The remaining four steps involve splitting the six-carbon molecule into two three-carbon molecules.
c. Glucose, a six-carbon sugar, enters the cell by simple diffusion and is primed and converted into glucose three-phosphate, which requires two ATP molecules. The remaining four steps involve splitting the six-carbon molecule into two three-carbon molecules.
d. Glucose, a six-carbon sugar, enters the cell by G protein mediation and is primed and converted into glucose three-phosphate, which requires two ATP molecules. The remaining four steps involve splitting the six-carbon molecule into two three-carbon molecules.

a. Glucose, a six-carbon sugar, enters the cell by passive transport and is primed and converted into glucose three-phosphate, which requires two ATP molecules. The remaining four steps involve splitting the six-carbon molecule into two three-carbon molecules.

Select the correct sequence concerning glucose catabolism. (1 point)
a. glycolysis → Pyruvate → Acetyl CoA → Electron Transport Chain → Krebs Cycle
b. glycolysis → Pyruvate → Acetyl CoA → Krebs Cycle → Electron Transport Chain
c. glycolysis → Acetyl CoA → Pyruvate → Electron Transport Chain → Krebs Cycle
d. glycolysis → Acetyl CoA → Pyruvate → Krebs Cycle → Electron Transport Chain

b. glycolysis → Pyruvate → Acetyl CoA → Krebs Cycle → Electron Transport Chain

A biochemist wants to control the initial substrate-level phosphorylation that occurs in the tracheal cells of grasshoppers once glucose has crossed the plasma membrane. This means that he will (1 point)
a. have to prevent cAMP from entering the tracheal cells.
b. have to prevent pyruvate reduction from occurring.
c. have to prevent glycolysis from occurring in the mitochondria.
d. have to prevent glycolysis from occurring in the cytoplasm.
e. have to prevent aerobic respiration in the cytoplasm.

d. have to prevent glycolysis from occurring in the cytoplasm.

What type of cell respiration occurs when an organic molecule accepts hydrogen
atoms? (1 point)
a. aerobic respiration
b. anaerobic respiration
c. fermentation
d. catabolism
e. digestion

b. anaerobic respiration

During aerobic respiration the final acceptor of the hydrogen atoms is (1 point)
a. oxygen.
b. carbon dioxide.
c. water.
d. glucose.
e. pyruvate.

a. oxygen.

A gram of fatty acid can yield how many more times the energy as one gram of
glucose?
a. 6 b. 5 c. 4 d. 3 e. 2A gram of fatty acid can yield how many more times the energy as one gram of
glucose?
a. 6 b. 5 c. 4 d. 3 e. 2

e. 2

Beta oxidation of these molecules converts them into acetyl-CoA, which can then
(1 point)
enter the Krebs cycle for energy derivation. These are
a. fatty acids.
b. amino acids.
c. ATP.
d. nucleic acids.
e. sugars.

a. fatty acids.

In muscle cells, fermentation produces not alcohol but
a. ATP.
b. NADH.
(1 point)
(1 point)
c. pyruvate.
d. kinetic energy.
e. lactic acid.

e. lactic acid.

Some prokaryotic organisms use nitrogen fixation to obtain organic nitrogen. Which of the following statements about nitrogen fixation is false? (1 point)
a. Nitrogen fixation requires the breaking a N≡N triple bond.
b. Nitrogen fixation evolved after anaerobic photosynthesis, but before aerobic respiration.
c. Nitrogen fixation can only occur in the presence of oxygen.
d. Nitrogen fixation evolved as a way to obtain organic nitrogen for production of proteins and
nucleic acids.

c. Nitrogen fixation can only occur in the presence of oxygen.

In order to lose weight and reduce body fat, a friend of yours decided to eliminate all fat from their diet, while consuming unrestricted amounts of carbohydrates. Aside from being an unhealthy way to try to lose weight, why would this approach be unsuccessful at reducing body fat? (1 point)
a. Excess acetyl-CoA from glycolysis will be channeled into production of body fat.
b. Excess acetyl-CoA from the Krebs cycle will be channeled into production of body fat.
c. Excess acetyl-CoA will undergo beta-oxidation to produce body fat.
d. Excess acetyl-CoA will undergo deamination to produce body fat.

b. Excess acetyl-CoA from the Krebs cycle will be channeled into production of body fat.

You arrive at your second home in the mountains looking forward to a relaxing vacation. Unfortunately, when you turn on the water 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. Which of the following molecules
would these bacteria use as an electron acceptor?
a. O2
b. H20
c. SO4
d. H2S

c. SO4

Yeast cells under anaerobic conditions (1 point)
a. die.
b. produce ethyl alcohol (ethanol).
c. produce oxygen.
d. switch to oxidative respiration.
e. push the glycolytic pathway backward.

b. produce ethyl alcohol (ethanol).

Regardless of the electron or hydrogen acceptor used, one of the products of fermentation is always (1 point)
a. ADP.
b. ATP.
c.
NAD+.
d. pyruvate.
e. alcohol.

c.
NAD+.

Since membranes are relatively impermeable to ions, most of the protons re-enter the matrix by passing through special channels in the inner mitochondrial membrane. Because of the inward flow of protons these channels allow the synthesisof (1point)
a. ADP from ATP and Pi.
b.ATP from ADP and Pi.
c. glucose from a pyruvate.
d. acetyl-CoA from pyruvate.
e. citrate from oxaloacetate and acetyl-CoA.

b.ATP from ADP and Pi.

21. The energy released in the mitochondrial electron transport chain is used to transport protons into the (1 point)
a. matrix.
b. cytoplasm.
c. ER.
d. inter-membrane space of mitochondria.
e. enzyme complex of the Krebs cycle.

d. inter-membrane space of mitochondria.

The electron transport chain consists of all of the following except (1 point)
a. NADH dehydrogenase.
b. cytochrome complex.
c. oxygenase.
d. cytochrome c oxidase.
e. ubiquinone, Q.

c. oxygenase.

The enzymes of the Krebs cycle are located in the (1 point)
a. cytoplasm.
b. inter-membrane space of mitochondria.
c. vesicles of the ER.
d. outer membrane of the mitochondria.
e. matrix of the mitochondria.

e. matrix of the mitochondria.

The electron transport chain, a series of membrane-associated electron carriers,
ATP from ADP and Pi. c. glucose from pyruvate.
d. acetyl-CoA from pyruvate.
e. citrate from oxaloacetate and acetyl-CoA.
loses most of the energy by driving several transmembrane
a. proton pumps.
b. electron pumps.
c. Na+/K+ pumps.
d.active transport pumps
e. water pumps

a. proton pumps.

The oxygen utilized in cellular respiration finally shows up as
a. CO2 .
b. ATP.
c. new O2.
d. H2O.
e. part of a sugar.

d. H2O.

The coenzyme electron carriers produced in the Krebs cycle are (1 point)
a. ATP and ADP.
b. pyruvate and acetyl-CoA.
c. FADH2 and NADH.
d. NAD and NADH.
e. NADH and ATP.

c. FADH2 and NADH.

A single glucose molecule can drive the Krebs cycle (1 point)
a. one turn.
b. two turns.
c. three turns.
d. four turns.
e. six turns.

b. two turns.

In the cyclic reaction sequence called the Krebs cycle, the following chemical events take place except (1 point)
a. the acetyl group is joined with a four carbon molecule, oxaloacetate.
b. the resulting six carbon molecule is oxidized.
c. electrons generated are used to produce NADH.
d. two carbons per cycle are made into CO2 molecules.
e. pyruvate molecules are restored to the cycle.

e. pyruvate molecules are restored to the cycle.

The decarboxylation of pyruvate produces all of the following except (1 point)
a. NADH.
b. acetyl-CoA.
c. CO2 .
d. ATP.

The decarboxylation of pyruvate produces all of the following except (1 point)
a. NADH.
b. acetyl-CoA.
c. CO2 .
d. ATP.

The decarboxylation step of oxidation of pyruvate takes place in the (1 point)
a. cytoplasm.
b. Golgi body.
c. ribosome.
d. mitochondrion.
e. nucleus.

d. mitochondrion.

The enzymes catalyzing the reactions of glycolysis are found in the (1 point)
a. mitochondria.
b. cytoplasm.
c. chloroplasts.
d. nucleus.
e. Golgi apparatus.

b. cytoplasm.

32. The end-product of glycolysis is (1 point)
a. ATP.
b. NAD+.
c. alcohol.
d. ADP.
e. pyruvate.

e. pyruvate.

All of the following are the end products of glycolysis except (1 point)
a. pyruvate.
b. ATP.
c. NADH.
d. NAD+.
e. energy.

d. NAD+.

A process common to all living organisms, aerobic and anaerobic, is (1 point)
a. glycolysis.
b. fermentation.
c. the Krebs cycle.
d. electron transport chain reactions.
e. pyruvate oxidation.

a. glycolysis.

In which of the following steps of glycolysis are two ATP molecules are required?
(1 point)
a. cleavage and rearrangement
b. glucose priming
c. oxidation
d. pyruvate formation
e. acetyl-CoA formation

b. glucose priming

In oxidative respiration, energy is harvested from glucose molecules in a sequence of four major pathways. Which of the following is not one of these four pathways? (1 point)
a. Krebs cycle
b. glycolysis
c. electron transfer through the transport chain
d. beta oxidation
e. pyruvate oxidation

d. beta oxidation

Out of the total amount of free energy potentially available from total oxidation of glucose, the number of ATP made by cells is equal to an energy efficiency of about (1 point)
a. 2%.
b. 25%.
c. 32%.
d. 75%.
e. 90%.

c. 32%.

The reaction, C6H6O6 + 6O2 = 6 CO2 + 6 H2O, when it occurs in living cells is known as (1 point)
a. aerobic fermentation.
b. anaerobic fermentation.
c. aerobic respiration.
d. glycolysis.
e. oxidative phosphorylation.

c. aerobic respiration.

Chemiosmotic generation of ATP is driven by (1 point)
a. Pi transfer through the plasma membrane.
b. the Na+/K+ pump. +
c. a difference in H+ concentration on the two sides of the mitochondrial membrane
d. osmosis of macromolecules.
e. large quantities of ADP.

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

Which of the following statements about fermentation is false? (1 point)
a. Fermentation takes place only in the absence of oxygen.
b. The recipient of hydrogen atoms is an organic molecule.
c. Water is not one of the by-products.
d. The Krebs cycle and electron transfer system do not occur.
e. Cells can only undergo one type of fermentation.

e. Cells can only undergo one type of fermentation.

At least 90% of organisms on the earth are heterotrophs. Examples include all of
a difference in H
the following except
a. plants.
b. fungi.
c. most eubacteria.
d. animals.
e. most protests.

a. plants.

In the absence of oxygen, hydrogen atoms generated by glycolysis are donated to organic molecules in a process called (1 point)
a. fermentation.
b. decarboxylation.
c. chemiosmosis.
d. electron transport chain reactions.
e. acetyl-CoA formation.

a. fermentation.

The first stage of cellular respiration, and the oldest in terms of evolution is (1 point)
a. decarboxylation.
b. deamination.
c. fermentation.
d. chemiosmosis.
e. glycolysis.

e. glycolysis.

In eukaryotes, the glycolytic reactions take place in the (1 point)
a. mitochondria of the cell.
b. cytoplasm of the cell.
c. ribosomes of the cell.
d. endoplasmic reticulum of each cell.
e. Golgi bodies of the cell.

b. cytoplasm of the cell.

An electron carrier that is used in harvesting energy from glucose molecules in a
series of gradual steps in the cytoplasm is
a. pyruvate.
b. cyclic AMP.
c. ATP.
d. NAD+.
e. NADH.

d. NAD+.

A molecule that stores energy by linking charged phosphate groups near each
other is called
a. ATP.
b. NADH.
c. FADH.
d. cyclic AMP.
e. pyruvate.

a. ATP.

High levels of citrate in the cell would result in which of the following? (1 point)
a. inhibition of phosphofructokinase and the slow down of glycolysis
b. inhibition of citrate synthase and the slow down of glycolysis
c. inhibition of phosphofructokinase and the slow down of the Krebs cycle
d. inhibition of citrate synthase and the slow down of the Krebs cycle

a. inhibition of phosphofructokinase and the slow down of glycolysis

If ATP synthase had a mutation in the F1 complex portion of the protein, which of the following functions is most likely to be affected? (1 point)
a. rotation of the rotor
b. flow of protons through the channel
c. conversion of ADP and Pi to ATP
d. insertion of the enzyme into the membrane

c. conversion of ADP and Pi to ATP

Your friend is having difficulty keeping track of the energy flow from glucose through glycolysis, the Krebs cycle and electron transport. Your best advice would be to (1 point)
a. follow ATP production.
b. follow the protons.
c. follow NAD+ production.
d. follow the electrons.

d. follow the electrons.

The chemical 2,4 dinitrophenol (DNP) is used in the manufacturing of dyes, wood preservatives, explosives, and insect control substances, and as a photographic developer. Products containing DNP are toxic because DNP uncouples oxidative phosphorylation. In a cell exposed to DNP, how many ATP molecules would be generated per molecule of glucose? (1 point)
a. 2
b. 4
c. 36
d. 38

b. 4

Which of the following molecules does not cross the inner membrane of the mitochondria? (1 point)
a. ATP
b. acetyl-CoA
c. pyruvate
d. oxygen

b. acetyl-CoA

You are examining some live cells in a Petri dish, when you begin to imagine what you would do if suddenly one of them were to burst into flames. Of course, in order for this to happen the cell would have to (1 point)
a. transfer electrons to intermediate electron carriers before transferring them to oxygen.
b. transfer electrons directly to oxygen, skipping the intermediate electron carriers.
c. transfer electrons directly to carbon dioxide, skipping the intermediate electron carriers.
d. transfer electrons to intermediate electron carriers before transferring them to carbon dioxide.

b. transfer electrons directly to oxygen, skipping the intermediate electron carriers.

53. After eating lunch on a very cold winter day, you begin the long walk across campus to your next class. During your walk you begin thinking about glucose catabolism and the high carbohydrate meal you just consumed. As the cold wind
follow NAD+ production.
picks up, you find yourself hoping that a lot of the energy released gets converted to heat. Which of the following statements concerning catabolism of glucose are false? (1 point)
a. From a chemical standpoint, glucose burning and glucose catabolism are very similar.
b. More energy is released as heat when glucose is burned rather than catabolized.
c. Cellular energy released can be as high as -720 kcal/mol glucose.
d. More total energy is released when glucose is burned rather than catabolized.

d. More total energy is released when glucose is burned rather than catabolized.

As a forensic pathologist, you have just completed an autopsy of a poisoning victim. After a thorough examination, you conclude that the victim died of cyanide poisoning. You know that cyanide binds to the cytochrome oxidase complex, and therefore list the official cause of death as suffocation due to cyanide exposure. However, a more technical explanation would be that all of the following aspects
of cellular respiration were inhibited except
(1 point)
a. the reduction of NAD+ and FAD.
b. electron transport.
c. oxidative phosphorylation.
d. proton pumping.

a. the reduction of NAD+ and FAD.

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, which stage of cellular respiration would be most affected? (1 point)
a. glycolysis
b. Krebs cycle
c. electron transport chain
d. fermentation

c. electron transport chain

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, which of the following might you expect to see in patients treated with antiviral drugs? (1 point)
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

d. an increase in lactic acid levels

If you were an anaerobic bacterium and needed to harvest energy, which of the following would be your best option? (1 point)
a. glycolysis and fermentation
b. fermentation and cellular respiration
c. Krebs cycle and fermentation
d. fermentation only

a. glycolysis and fermentation

Coenzyme electron carrier; associated with Krebs cycle only.
A. ATP
B. FAD
C. G3P
D. NAD
E. acetyl-CoA

B. FAD

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