Chapter 11 Practice

The sum total of all chemical reactions occurring in a cell is called
A. anabolism.
B. catabolism.
C. metabolism.
D. none of the choices

C. metabolism.

T/F
Although most metabolic reactions are freely reversible, a few irreversible catabolic steps are bypassed during biosynthesis with special enzymes that catalyze the reverse reaction in order to allow for independent regulation of catabolic and anabolic pathways.

True

T/F
Metabolic pathways can be either catabolic or anabolic but not both.

False

__________ pathways are those that function both catabolically and anabolically.

Amphibolic

T/F
The catabolism of glucose begins with one or more of the glycolytic pathways that yield pyruvate.

True

____________ ____________ is a process that can completely catabolize an organic energy source to CO2 using the glycolytic pathways and TCA cycle with O2 as the terminal electron acceptor for an electron transport chain.

aerobic respiration

T/F
Very few gram positive bacteria utilize the Entner-Doudoroff glycolytic pathway.

True

T/F
Some aerobic bacteria lack the Entner-Doudoroff and Embden-Meyerhoff pathways and instead use the pentose phosphate pathway for glycolysis

False

T/F
An organism may use glycolysis and the pentose phosphate pathway simultaneously.

True

The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhoff pathway in prokaryotes is
A. 2.
B. 36.
C. 38.
D. 85.

A. 2.

The net gain of ATP per molecule of glucose metabolized to pyruvate using Entner-Doudoroff pathway is
A. 4.
B. 2.
C. 1.
D. 0.

C. 1.

The pentose phosphate pathway produces
A. CO2.
B. NADPH.
C. glyceraldehyde 3-phosphate.
D. all of the choices.

D. all of the choices.

The synthesis of ATP from ADP and Pi, when coupled with an exergonic chemical reaction is called __________ phosphorylation.
A. chemiosmotic
B. oxidative
C. substrate-level
D. conformational change

C. substrate-level

The most common pathway for conversion of glucose to pyruvate is
A. Entner-Doudoroff.
B. Pentose phosphate.
C. Embden-Meyerhoff.
D. mixed acid fermentation.

C. Embden-Meyerhoff.

The TCA cycle generates all of the following from each acetyl-CoA molecule oxidized except
A. three NADH molecules.
B. two CO2 molecules.
C. one FADH2 molecule.
D. two ATP or GTP molecules

D. two ATP or GTP molecules.

The pyruvate dehydrogenase complex oxidizes and cleaves pyruvate to form one CO2 and
A. lactate.
B. isocitric acid.
C. acetyl-CoA.
D. succinyl-CoA.

C. acetyl-CoA.

After glycolysis, pyruvate is oxidized to one CO2 and the two-carbon molecule acetyl-CoA by a multienzyme system called the ________ ________ complex.

pyruvate dehydrogenase

TCA cycle enzymes are found in the _____________ _________ of eukaryotic cells.

mitochondrial matrix

In the TCA cycle, two carbons are removed from citric acid in the form of __________, thereby regenerating oxaloacetate to complete the cycle.
A. acetyl-CoA
B. ethanol
C. carbon dioxide
D. methanol

C. carbon dioxide

In the TCA cycle, two carbons in the form of __________ are added to oxaloacetate at the start of the cycle.
A. acetyl-CoA
B. ethanol
C. carbon dioxide
D. methanol

A. acetyl-CoA

The major function(s) of the TCA cycle is(are)
A. energy production.
B. provision of carbon skeletons for biosynthesis of cell components.
C. electron transport.
D. energy production and provision of carbon skeletons for biosynthesis of cell components.

D. energy production and provision of carbon skeletons for biosynthesis of cell components

When mitochondria pass electrons donated by NADH through the electron transport chain to molecular oxygen, a theoretical maximum of __________ molecules of ATP can be made per oxygen molecule reduced.

three

The hypothesis that proton motive force drives ATP synthesis is called the __________ hypothesis.

chemiosmotic

The most commonly accepted hypothesis for the production of ATP that results from electron transport system is called the __________ hypothesis.

chemiosmotic

Bacterial electron transport chains may be comprised of fewer components and have lower P/O ratios than mitochondrial transport chains

TRUE

The electron transport systems in eukaryotes and prokaryotes use different electron carriers.

TRUE

In addition to being used in the making of ATP, proton motive force is used directly to power the rotation of bacterial flagella.

TRUE

Differences between mitochondrial and E. coli electron transport chains include the following:
A. The E. coli chain contains a different array of cytochromes.
B. The fundamental principles on which they operate are different.
C. Higher P/O values are observed in E. coli.
D. The electron transport change does not involve membranes in E. coli.

A. The E. coli chain contains a different array of cytochromes.

Which of the following is NOT true regarding ATP synthases?
A. They require proton motive force to make ATP.
B. They span the inner membrane of mitochondria.
C. The proton flow is outward during ATP synthesis.
D. The subunits of ATP synthase undergo conformational changes during ATP production.

C. The proton flow is outward during ATP synthesis.

The theoretical maximum net gain of ATP per molecule of glucose metabolized aerobically in eukaryotes is
A. 2.
B. 32.
C. 38.
D. 85.

B. 32.

Production of ATP using the energy liberated when electrons from reduced chemical bonds are passed through the electron transport system is generally referred to as __________.
A. chemiosmotic
B. respiration
C. substrate-level
D. conformational change

B. respiration

Mitochondrial electron transport takes place
A. on the outer mitochondrial membrane.
B. on the inner mitochondrial membrane.
C. in the fluid matrix of the mitochondria.
D. on the outer mitochondrial membrane and on the inner mitochondrial membrane.

B. on the inner mitochondrial membrane.

In higher eukaryotes, most aerobically generated ATP is produced by
A. glycolysis.
B. the TCA cycle.
C. a membrane bound proton translocating ATP synthase during oxidative phosphorylation.
D. all of these generate equal amounts of ATP.

C. a membrane bound proton translocating ATP synthase during oxidative phosphorylation.

The number of ATP molecules generated per atom of oxygen that is reduced when electrons are passed from NADH or reduced FAD (FADH) to O2 is called the
A. utilization ratio.
B. energy yield.
C. P/O ratio.
D. phosphorylation coefficient.

C. P/O ratio.

In aerobic conditions, it takes __________ sugar to produce the same amount of ATP when compared to anaerobic conditions.
A. more
B. less
C. the same amount of

B. less

Prokaryotes may use several different terminal oxidases for the electron transport system.

TRUE

Reduction of nitrate to nitrite by Paracoccus denitrificans is an example of anaerobic respiration.

TRUE

When cells of a facultative anaerobe such as Paracoccus denitrificans are growing under anaerobic conditions and using nitrate as the terminal electron acceptor, ______________ nitrate reduction is occurring.

dissimilatory

Which of the following can be used as electron acceptors during anaerobic respiration?
A. nitrate
B. sulfate
C. carbon dioxide
D. all of the choices

D. all of the choices

Organisms that form lactate, ethanol, and CO2 as end products of glucose metabolism are called __________ fermenters.

heterolactic

Fermentation involves the use of pyruvate and/or other organic molecules as electron acceptors.

TRUE

In the process of fermentation an organic substrate, such as glucose, is reduced and an intermediate of the pathway, such as pyruvate, is oxidized.

FALSE

Organisms that directly reduce almost all of their pyruvate to lactate are called __________ fermenters.

homolactic

Oxygen is always required for the regeneration of NAD from NADH.

FALSE

Large external polysaccharides are degraded by bacteria and archaea using ________ ________, which secrete these substances outside the cell.

hydrolytic enzymes

Disaccharides and polysaccharides can be processed as nutrients after first being cleaved to monosaccharides by either __________ or __________.

hydrolysis; phosphorolysis

Fatty acids are metabolized by the __________ pathway.
A. alpha-oxidation
B. beta-oxidation
C. gamma-oxidation
D. delta-oxidation

B. beta-oxidation

During breakdown of fatty acids, carbons are removed __________ at a time with each turn of the cycle, and two carbon units are released as __________.
A. one; carbon dioxide
B. one; methane
C. two; acetyl-CoA
D. two; ethanol

C. two; acetyl-CoA

Proteins are catabolized by hydrolytic cleavage to amino acids by the action of enzymes called __________.

proteases

Amino acids are processed first by the removal of the amino group through
A. deamination.
B. transamination.
C. phosphorolytic cleavage.
D. deamination or transamination

D. deamination or transamination

Nitrification of ammonia occurs when ammonia is first converted to nitrite and then is converted to nitrate by the nitrogen-fixing bacteria.

FALSE

_______________ is a two-step process that depends on the activity of at least two genera to carry out the oxidation of ammonia to nitrate.

Nitrification

Which of the following may be used as sources of energy by chemolithotrophs?
A. Hydrogen gas.
B. Reduced nitrogen compounds.
C. Reduced sulfur compounds.
D. All of the choices.

D. All of the choices.

How many molecules of ATP are needed to reduce one molecule of carbon dioxide to carbohydrate by oxygenic phototrophs during the dark reactions of photosynthesis?
A. 2
B. 3
C. 4
D. 10-12

B. 3

How many molecules of NADPH are needed to reduce one molecule of carbon dioxide to carbohydrate by oxygenic phototrophs during the dark reactions of photosynthesis?
A. 2
B. 3
C. 4
D. 10-12

A. 2

How many quanta of light are needed to reduce one molecule of carbon dioxide to carbohydrate during photosynthesis?
A. 2
B. 3
C. 4
D. 10-12

D. 10-12

Photosynthetic organisms serve as the base for most food chains in the biosphere.

TRUE

All eukaryotic photosynthesizers are oxygenic.

TRUE

In the process of noncyclic photophosphorylation
A. water is split to form oxygen gas.
B. electrons from water flow through electron transport chains resulting in synthesis of ATP and NADPH.
C. photosystems I and II are both required.
D. all of the choices

D. all of the choices

In the process of __________, ATP is synthesized when excited electrons from chlorophyll P700 pass through a series of electron carriers then return to chlorophyll P700.
A. photosynthesis
B. cyclic photophosphorylation
C. acyclic photophosphorylation
D. noncyclic photophosphorylation

B. cyclic photophosphorylation

Photosynthetic electron transport in cyanobacteria takes place
A. on the plasma membrane.
B. in the chloroplast.
C. in the cytoplasm.
D. on the thylakoid membranes.

D. on the thylakoid membranes.