The total of all chemical reactions occurring in a cell is called ________________.
answer
Metabolism
question
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 oder to all for independent regulation of catabolic and anabolic pathways.
answer
TRUE
question
____________ pathways are those that function both catabolically and anabolically.
answer
Amphibolic
question
The catabolism of glucose begins with one or more of the glycolytic pathways that yield pyruvate.
answer
TRUE
question
__________________ __________________ 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.
answer
Aerobic Respiration
question
Very few Gram-positive bacteria utilize the Entner-Duodoroff glycolytic pathway.
answer
TRUE
question
Some aerobic bacteria lack the Entner-Duodoroff and Embden-Meyerhoff pathways and instead use the pentose phosphate pathway for glycolysis.
answer
FALSE
question
An organism may use glycolysis and the pentose phosphate pathway simultaneously.
answer
TRUE
question
The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhof pathway in prokaryotes is _________________.
answer
2
question
The net gain of ATP per molecule of glucose metabolized to pyruvate using Entner-Doudoroff pathway is ____________________.
answer
1
question
The pentose phosphate pathway produces ______________________.
answer
A) CO2
B) NADPH
C) glyceraldehyde 3-phosphate
D) All of the choices are correct <------------
question
The synthesis of ATP from ADP and Pi, when coupled with an exergonic chemical reaction is called ______________ phosphorylation.
answer
substrate-level
question
The most common pathway for conversion of glucose to pyruvate is _________________.
answer
Embden-Meyerhoff
question
The TCA cycle generates all of the following from each acetyl-CoA molecule oxidized except ______________.
answer
two ATP or GTP molecules
question
The pyruvate dehydrogenase complex oxidizes and cleaves pyruvate to form one CO2 and _____________.
answer
acetyl-CoA
question
After glycolysis, pyruvate is oxidized to one CO2 and the two-carbon molecule acetyl-CoA by a multienzyme system called the ______________ ________________ complex.
answer
Pyruvate dehydrogenase
question
TCA cycle enzymes are found in the _____________ _________ of eukaryotic cells.
answer
mitochondrial matrix
question
In the TCA cycle, two carbons are removed from the citric acid in the form of ____________, thereby regenerating oxaloacetate to complete the cycle.
answer
carbon dioxide
question
In the TCA cycle, two carbons in the form of ______________ are added to oxaloacetate at the start of the cycle.
answer
acetyl-CoA
question
The major function(s) of the TCA cycle is (are) ____________________.
answer
energy production and provision of carbon skeletons for biosynthesis of cell components.
question
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.
answer
Three
question
The hypothesis that proton motive force drives ATP synthesis is called the _______________ hypothesis.
answer
chemiosmotic
question
The most commonly accepted hypothesis for the production of ATP that results from electron transport system is called the _____________ hypothesis.
answer
chemiosmotic
question
Bacterial electron transport chains may be comprised of fewer components and have lower phosphate to oxygen (P/O) ratios than mitochondrial transport chains.
answer
TRUE
question
The electron transport systems in eukaryotes and prokaryotes use different electron carriers.
answer
TRUE
question
In addition to being used in the making of ATP, a proton motive force is used directly to power the rotation of bacterial flagella.
answer
TRUE
question
Differences between mitochondrial and E. coli electron transport chains include which of the following?
answer
The E. coli chain contains a different array of cytochromes.
question
Which of the following is NOT true regarding ATP synthases?
answer
The proton flow is outward during ATP synthesis.
question
The theoretical maximum net gain of ATP per molecule of glucose metabolized aerobically in eukaryotes is ________.
answer
38
question
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 ________.
answer
respiration
question
Mitochondrial electron transport takes place ________.
answer
on the inner mitochondrial membrane
question
In higher eukaryotes, most aerobically generated ATP is produced by ________.
answer
a membrane-bound proton translocating ATP synthase during oxidative phosphorylation
question
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 ________.
answer
P/O ratio
question
In aerobic conditions, it takes ________ sugar to produce the same amount of ATP when compared to anaerobic conditions.
answer
less
question
Prokaryotes may use several different terminal oxidases for the electron transport system.
answer
TRUE
question
Reduction of nitrate to nitrite by Paracoccus denitrificans is an example of anaerobic respiration.
answer
TRUE
question
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.
answer
dissimilatory
question
Which of the following can be used as electron acceptors during anaerobic respiration?
answer
A) Nitrate
B) Sulfate
C) Carbon dioxide
D) All of the choices are correct. <--------------
question
Organisms that form lactate, ethanol, and CO2 as end products of glucose metabolism are called ________ fermenters.
answer
heterolactic
question
Fermentation involves the use of pyruvate and/or other organic molecules as electron acceptors.
answer
TRUE
question
In the process of fermentation an organic substrate, such as glucose, is reduced and an intermediate of the pathway, such as pyruvate, is oxidized.
answer
FALSE
question
Organisms that directly reduce almost all of their pyruvate to lactate are called ________ fermenters.
answer
homolactic
question
Oxygen is always required for the regeneration of NAD from NADH.
answer
FALSE
question
Large external polysaccharides are degraded by bacteria and archaea using ________________, which they secrete outside the cell.
answer
hydrolytic enzymes
question
Disaccharides and polysaccharides can be processed as nutrients after first being cleaved to monosaccharides by either ________ or ________.
answer
hydrolysis; phosphorolysis
question
Fatty acids are metabolized by the ________ pathway.
answer
beta-oxidation
question
During breakdown of fatty acids, carbons are removed ________ at a time with each turn of the cycle, and two carbon units are released as ________.
answer
two; acetyl-CoA
question
Proteins are catabolized by hydrolytic cleavage to amino acids by the action of enzymes called ________.
answer
proteases
question
Amino acids are processed first by the removal of the amino group through ________.
answer
deamination or transamination
question
Nitrification of ammonia occurs when ammonia is first converted to nitrite and then is converted to nitrate by the nitrogen-fixing bacteria.
answer
FALSE
question
________ is a two-step process that depends on the activity of at least two genera to carry out the oxidation of ammonia to nitrate.
answer
Nitrification
question
Which of the following may be used as sources of energy by chemolithotrophs?
answer
A) Hydrogen gas
B) Reduced nitrogen compounds
C) Reduced sulfur compounds
D) All of the choices are correct. <------------
question
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?
answer
3
question
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?
answer
2
question
How many quanta of light are needed to reduce one molecule of carbon dioxide to carbohydrate during photosynthesis?
answer
10-12
question
All prokaryotic photosynthesizers are anoxygenic.
answer
FALSE
question
Photosynthetic organisms serve as the base for most food chains in the biosphere.
answer
TRUE
question
All eukaryotic photosynthesizers are oxygenic.
answer
TRUE
question
In the process of noncyclic photophosphorylation, ________.
answer
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 are correct. <---------------
question
In the process of ________, ATP is synthesized when excited ele
ctrons from chlorophyll P700 pass through a series of electron carriers then return to chlorophyll P700.
answer
cyclic photophosphorylation
question
Photosynthetic electron transport in cyanobacteria takes place ________.
answer
on the thylakoid membranes
question
Select the terms that describe an organism's carbon source.
answer
A) Heterotroph
D) Autotroph
question
The terms phototroph and chemotroph refer to an organism's source of ________.
answer
energy
question
A newly described bacterial species has been shown to use CO2
as its carbon source. Its energy source and its source of reducing power (electrons) are inorganic chemicals. Which term
would best describe this nutritional type?
answer
Chemolithoautotroph
question
Which nutritional classification would you predict to fit most of the well-known members of the human microbiome?
answer
Chemoorganoheterotrophs
question
Processes that supply ATP, reducing power, and precursor metabolites are collectively referred to as ________ reactions.
answer
fueling
question
In most cases, fueling reactions are ________ reactions.
answer
catabolic
question
An organism can fit into only one nutritional pattern, such as photoheterotrophy, and cannot change if the environmental conditions change.
answer
FALSE
question
An organism can take advantage of energy available from both light and from organic molecules and exhibit both phototrophy and chemoorganotrophy.
answer
TRUE
question
Indicate the processes below that represent the basic types of chemoorganotrophic metabolism.
answer
B) Aerobic respiration
C) Fermentation
E) Anaerobic respiration
question
Aerobic respiration, anaerobic respiration, and fermentation are the three basic types of ________.
answer
chemoorganoheterotrophic metabolism
question
Glycolysis and the TCA cycle are two of the most important catabolic pathways in chemoorganotrophs.
answer
TRUE
question
What distinguishing feature characterizes aerobic and anaerobic respiration but does not play a role in fermentation pathways?
answer
The presence of an electron transport chain
question
The six carbons of the glucose molecule that enter the cell respiration pathway end up in/as ______________ by the end of the process.
answer
carbon dioxide
question
Indicate the products of aerobic respiration.
answer
A) Water
C) CO2
E) ATP
question
Which of the following produces the most ATP during aerobic respiration?
answer
Electron transport chain and chemiosmosis
question
During glycolysis, ATP is produced when 1,3 bisphosphoglycerate
transfers a phosphate to ADP forming ATP. This is an example of ________.
answer
substrate-level phosphorylation
question
In order for a substance to transfer a phosphate to ADP in a substrate-level phosphorylation reaction, which of the following must be true?
answer
The phosphate donor must have a higher phosphate transfer potential than ATP.
question
Whereas the Embden-Meyerhof pathway produces two molecules of pyruvate (net) for each glucose, the Entner-Doudoroff pathway produces one molecule each of ________ and ________.
answer
pyruvate; glyceraldehyde
question
Which of the following is the major glycolytic pathway used by plants and animals?
answer
Embden-Meyerhof pathway
question
The pentose phosphate pathway is the major glycolytic pathway used by archaea.
answer
FALSE
question
Which of the following names refer to the tricarboxlic acid cycle?
answer
A) Krebs cycle
D) Citric acid cycle
question
The terms Krebs cycle, tricarboxylic acid cycle, and citric acid cycle all refer to the same process.
answer
TRUE
question
Which of the following is produced in largest numbers by the TCA cycle?
answer
NADH
question
The TCA cycle is located in the ________ of bacteria, and in the ________ of eukaryotes.
answer
cytoplasm; mitochondrial matrix
question
The major difference between aerobic and anaerobic respiration is the final electron acceptor at the end of the electron transport chain.
answer
TRUE
question
When nitrate is used as a final electron acceptor by bacteria growing in anoxic soils, the nitrogen is no longer available for the construction of precursor metabolites. This is referred to
as ________.
answer
dissimilatory nitrate reduction
question
The amount of ATP produced during anaerobic respiration is ________ that produced during aerobic respiration, because the difference in the standard reduction potential between NADH and the final electron acceptor is ________.
answer
less than; smaller
question
Which of the following are consequences of anaerobic respiration?
(Check all that apply.)
answer
A) Some bacteria are able to readily survive in both well-oxygenated as well as anoxic environments.
B) Some bacteria may cause denitrification.
D) Bacteria are able to reduce the levels of
NO3 − in sewage plant effluents.
question
How is ATP produced during fermentation?
answer
Substrate-level phosphorylation
question
How does a fermenter generate proton motive force (PMF) to drive active transport?
answer
Fermenters can reverse the direction of the ATP synthase to generate PMF.
question
How does the phosphorylation of galactose differ from the phosphorylation of glucose, mannose, and fructose prior to catabolism?
answer
Phosphorylation of galactose requires UTP to phosphorylate galactose-1-phosphate
question
Complete catabolism of lactose requires ________.
answer
ATP, UTP, NAD, and appropriate enzymes
question
What enzymes hydrolyze proteins, releasing amino acids?
answer
Proteases
question
A ________ hydrolyzes a protein into its constituent amino acid monomers and a _______ enzyme removes amino groups from the amino acids.
answer
protease; deaminase
question
________ refers to the removal of an amino group from an amino acid. One mechanism for this removal is ________, in which the amino group is transferred to an acceptor molecule.
answer
Deamination; transamination
question
The substances that donate electrons to the electron transport chains of chemolithotrophs are ________.
answer
inorganic compounds
question
Most chemolithotrophs have electron transport chains that terminate with O2 as the final electron acceptor.
answer
TRUE
question
Many chemolithotrophs are able to produce more ATP from oxidation of their inorganic energy source than chemoheterotrophs produce from the aerobic oxidation of glucose.
answer
FALSE
question
Chemolithotrophs generally derive ________ ATP from oxidation of inorganic substrates because the reduction potentials of those substrates are much more ________ than the reduction potential of organic substrates.
answer
less; positive
question
________ is an aerobic chemolithotrophic process that ultimately oxidizes ammonia to nitrate, whereas ________ is a form of anaerobic respiration involving the oxidation of an organic compound using an oxidized nitrogenous compound, such as nitrate, as the terminal
electron acceptor.
answer
Nitrification; denitrification
question
All forms of phototropy "harvest" light energy to fix carbon, producing sugar.
answer
FALSE
question
Photoheterotrophs that use light to generate ATP, but do not fix CO2________. (Check all that apply.)
answer
D) would best be described as phototropic
E) would use the light reactions but not the Calvin cycle
question
Chlorophyll a and chlorophyll b as well as the accessory pigments are arranged in an antenna array with a reaction center chlorophyll.
These antenna arrays with the reaction center chlorophyll are known as ________.
answer
photosystems
question
Which of the following described roles attributed to accessory pigments such as carotenes and phycobiliproteins? (Check all that apply.)
answer
A) These pigments absorb light in ranges not absorbed by chlorophylls and transfer the energy to
chlorophylls.
B) These pigments extend the spectrum of wavelengths that will drive photosynthesis.
D) Accessory pigments protect organisms from potentially damaging intense sunlight.
question
In what ways are oxidative phosphorylation and photophosphorylation similar?
answer
B) An electron transport chain is used
C) Proton motive force is generated
E) ATP synthase enzyme phosphorylates ADP to make ATP
question
Consider the metabolism of a chlorophyll
-based phototroph. In oxidative phosphorylation
during cell respiration, the source of energy is ________ whereas in photophosphorylation the
source of energy is ________.
answer
highly reduced organic compounds ; light
question
The Embden-Meyerhof, Entner-Doudoroff and pentose phosphate pathways all bring about the reduction of coenzymes (either NAD+
or NADP+). The reduced coenzymes ________.
answer
provide reducing power to fuel subsequent reactions
question
The TCA cycle ________.
answer
provides reducing power in the form of NADH and FADH2, and precursor molecules for
anabolic reactions
question
The TCA cycle begins when ________.
answer
pyruvate from the glycolytic pathway is oxidized to acetyl-CoA, which is added to oxaloacetate
question
Oxidative decarboxylation takes place when pyruvate from the glycolytic pathway is oxidized, producing acetyl-CoA along with one CO2 and one NADH.
answer
TRUE
question
Which of the following statements is true regarding the effect of electron transport chain
length on energy production?
answer
As electrons are passed from carrier to carrier, each oxidation releases enough energy to
actively transport protons across a membrane, thus, the more carriers, the greater the proton
motive force produced.
question
The oxidation of glucose to CO2 and H2
O with the subsequent production of energy is best
reflected in which of the following statements?
answer
Glucose is oxidized in a stepwise fashion beginning with a glycolytic pathway and continuing
with the TCA cycle where the remainder of the energy from the glucose is harnessed in reduced
coenzymes, which transport electrons to an electron transport chain where ATP is made by
oxidative phosphorylation.
question
The catabolism of glucose through a glycolytic pathway, followed by the TCA cycle and culminating in ATP production via the formation of a proton motive force in the electron transport chain, represents the overall reduction of glucose.
answer
FALSE
question
The energy source for substrate
-level phosphorylation (SLP) differs from that of oxidative
phosphorylation (OP) in that ________.
answer
OP is driven using energy provided by a proton motive force, whereas the energy to add a
phosphate group to ADP during SLP comes from the direct transfer of a phosphate group from a
molecule with a higher phosphate transfer potential than ATP
question
Chemolithotrophs obtain their energy from ________.
answer
inorganic molecules that are oxidized, providing electrons to create a proton motive force that
drives oxidative phosphorylation
question
Which statement best describes the concept of electron bifurcation?
answer
A flavoenzyme oxidizes an electron donor and directs two electrons to two different recipients, one being
an exothermic reduction that pulls the simultaneous endothermic reduction to completion.
question
Flavoenzymes oxidize an electron donor then direct the two electrons to two different recipients having different reduction potentials.
answer
TRUE
question
Endergonic reactions in cells do not happen spontaneously, that is, they require an input of energy. Coupling such reactions with exothermic ones, such as the hydrolysis of ATP drives the
reaction for ward. Certain organisms are able to bypass the need for ATP or a proton motive force by ________.
answer
tightly coupling an endergonic and an exergonic reduction so the exergonic reduction can
drive the completion of the endergonic one in a process known as e
lectron bifurcation
question
Electron bifurcation is a useful way for organisms to circumvent the need for ATP hydrolysis and/or a proton motive force because it tightly couples reactions that are thermodynamically unfavorable with those that occur spontaneously, providing an excess of
energy to drive the former.
answer
TRUE
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