Microbio Class Ch 11
The net gain of ATP per molecule of glucose metabolized to pyruvate using Entner-Doudoroff pathway is _________.
1
The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhof pathway in prokaryotes is _________.
2
The theoretical maximum net gain of ATP per molecule of glucose metabolized aerobically in eukaryotes is _________.
32
Complete catabolism of lactose requires _________.
ATP, UTP, NAD, and appropriate enzymes
Indicate the products of aerobic respiration.
All choices are correct. water, CO2, ATP, NADH
The pentose phosphate pathway produces _________.
All of the choices are correct. CO2 NADPH glyceraldehyde 3-phosphate
Which of the following may be used as sources of energy by chemolithotrophs?
All of the choices are correct. Hydrogen gas Reduced nitrogen compounds Reduced sulfur compounds
Which of the following can be used as electron acceptors during anaerobic respiration?
All of the choices are correct. Nitrate Sulfate Carbon dioxide
Which of the following statements is true regarding the effect of electron transport chain length on energy production?
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.
In the TCA cycle, two carbons are removed from citric acid in the form of __________, thereby regenerating oxaloacetate to complete the cycle.
CO2
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?
Chemolithoautotroph
Which nutritional classification would you predict to fit most of the well-known members of the human microbiome?
Chemoorganoheterotrophs
___________ 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.
Deamination; transamination
Which of the following produces the most ATP during aerobic respiration?
Electron transport chain and chemiosmosis
Which of the following is the major glycolytic pathway used by plants and animals?
Embden-Meyerhof pathway
The most common pathway for conversion of glucose to pyruvate is _________.
Embden-Meyerhoff
An organism can fit into only one nutritional pattern, such as photoheterotrophy, and cannot change if the environmental conditions change.
False
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
Many chemolithotrophs are able to produce more ATP from oxidation of their inorganic energy source than chemoheterotrophs produce from the aerobic oxidation of glucose.
False
Metabolic pathways can be either catabolic or anabolic but not both.
False
Nitrification of ammonia occurs when ammonia is first converted to nitrite and then is converted to nitrate by the nitrogen-fixing bacteria.
False
Oxygen is always required for the regeneration of NAD from NADH.
False
Some aerobic bacteria lack the Entner-Doudoroff and Embden-Meyerhoff pathways and instead use the pentose phosphate pathway for glycolysis.
False
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.
False
The pentose phosphate pathway is the major glycolytic pathway used by archaea.
False
How does a fermenter generate proton motive force (PMF) to drive active transport?
Fermenters can reverse the direction of the ATP synthase to generate PMF.
The oxidation of glucose to CO2 and H2O with the subsequent production of energy is best reflected in which of the following statements?
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.
Which of the following names refer to the tricarboxlic acid cycle?
Krebs Cycle, citric acid cycle
Which of the following is produced in largest numbers by the TCA cycle?
NADH
__________ 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
The energy source for substrate-level phosphorylation (SLP) differs from that of oxidative phosphorylation (OP) in that __________.
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
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 _________.
P/O ratio
How does the phosphorylation of galactose differ from the phosphorylation of glucose, mannose, and fructose prior to catabolism?
Phosphorylation of galactose requires UTP to phosphorylate galactose-1-phosphate
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
An organism can take advantage of energy available from both light and from organic molecules and exhibit both phototrophy and chemoorganotrophy.
True
An organism may use glycolysis and the pentose phosphate pathway simultaneously.
True
Bacterial electron transport chains may be comprised of fewer components and have lower phosphate to oxygen (P/O) ratios than mitochondrial transport chains.
True
Fermentation involves the use of pyruvate and/or other organic molecules as electron acceptors.
True
Glycolysis and the TCA cycle are two of the most important catabolic pathways in chemoorganotrophs.
True
In addition to being used in the making of ATP, a proton motive force is used directly to power the rotation of bacterial flagella.
True
Most chemolithotrophs have electron transport chains that terminate with O2 as the final electron acceptor.
True
Oxidative decarboxylation takes place when pyruvate from the glycolytic pathway is oxidized, producing acetyl-CoA along with one CO2 and one NADH.
True
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
The catabolism of glucose begins with one or more of the glycolytic pathways that yield pyruvate.
True
The electron transport systems in eukaryotes and prokaryotes use different electron carriers.
True
The major difference between aerobic and anaerobic respiration is the final electron acceptor at the end of the electron transport chain.
True
The terms Krebs cycle, tricarboxylic acid cycle, and citric acid cycle all refer to the same process.
True
Very few Gram-positive bacteria utilize the Entner-Doudoroff glycolytic pathway.
True
In higher eukaryotes, most aerobically generated ATP is produced by _________.
a membrane-bound proton translocating ATP synthase during oxidative phosphorylation
In the TCA cycle, two carbons in the form of __________ are added to oxaloacetate at the start of the cycle.
acetyl-CoA
The pyruvate dehydrogenase complex oxidizes and cleaves pyruvate to form one CO2 and _________.
acetyl-CoA
____________ ____________ 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
__________ pathways are those that function both catabolically and anabolically.
amphibolic
Fatty acids are metabolized by the __________ pathway.
beta-oxidation
The six carbons of the glucose molecule that enter the cell respiration pathway end up in/as _______ ______ by the end of the process.
carbon dioxide
In most cases, fueling reactions are __________ reactions.
catabolic
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
Aerobic respiration, anaerobic respiration, and fermentation are the three basic types of _________.
chemoorganoheterotrophic metabolism
Select the terms that describe an organism's carbon source.
chemotroph, autotroph
The TCA cycle is located in the _________ of bacteria, and in the _________ of eukaryotes.
cytoplasm; mitochondrial matrix
Amino acids are processed first by the removal of the amino group through _________.
deamination or transamination
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
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 _________.
dissimilatory nitrate reduction
The terms phototroph and chemotroph refer to an organism's source of _________.
energy
The major function(s) of the TCA cycle is(are) _________.
energy production and provision of carbon skeletons for biosynthesis of cell components
Processes that supply ATP, reducing power, and precursor metabolites are collectively referred to as ____________ reactions.
fueling
Organisms that form lactate, ethanol, and CO2 as end products of glucose metabolism are called __________ fermenters.
heterolactic
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 __________.
highly reduced organic compounds; light
Organisms that directly reduce almost all of their pyruvate to lactate are called __________ fermenters.
homolactic
Disaccharides and polysaccharides can be processed as nutrients after first being cleaved to monosaccharides by either __________ or __________.
hydrolysis; phosphorolysis
Large external polysaccharides are degraded by bacteria and archaea using ________ ________, which they secrete outside the cell.
hydrolytic enzymes
The substances that donate electrons to the electron transport chains of chemolithotrophs are ___________.
inorganic compounds
Chemolithotrophs obtain their energy from __________.
inorganic molecules that are oxidized, providing electrons to create a proton motive force that drives oxidative phosphorylation
In aerobic conditions, it takes __________ sugar to produce the same amount of ATP when compared to anaerobic conditions.
less
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 __________.
less than; smaller
The total of all chemical reactions occurring in a cell is called _________.
metabolism
TCA cycle enzymes are found in the __________ _________ of eukaryotic cells.
mitochondrial matrix
Mitochondrial electron transport takes place _________.
on the inner mitochondrial membrane
Indicate the processes below that represent the basic types of chemoorganotrophic metabolism.
photosynthesis, oxidation-reduction
A ________ hydrolyzes a protein into its constituent amino acid monomers and a _________ enzyme removes amino groups from the amino acids.
protease, deaminase
Proteins are catabolized by hydrolytic cleavage to amino acids by the action of enzymes called __________.
proteases
What enzymes hydrolyze proteins, releasing amino acids?
proteases
The Embden-Meyerhof, Entner-Doudoroff and pentose phosphate pathways all bring about the reduction of coenzymes (either NAD+ or NADP+). The reduced coenzymes __________.
provide reducing power to fuel subsequent reactions
The TCA cycle __________.
provides reducing power in the form of NADH and FADH2, and precursor molecules for anabolic reactions
After glycolysis, pyruvate is oxidized to one CO2 and the two-carbon molecule acetyl-CoA by a multienzyme system called the ________ ________ complex.
pyruvate dehydrogenase
The TCA cycle begins when __________.
pyruvate from the glycolytic pathway is oxidized to acetyl-CoA, which is added to oxaloacetate
Whereas the Embden-Meyerhof pathway produces two molecules of pyruvate (net) for each glucose, the Entner-Doudoroff pathway produces one molecule each of ___________ and ____________.
pyruvate; glyceraldehyde
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 _________.
respiration
The synthesis of ATP from ADP and Pi, when coupled with an exergonic chemical reaction is called __________ phosphorylation.
substrate-level
During glycolysis, ATP is produced when 1,3 bisphosphoglycerate transfers a phosphate to ADP forming ATP. This is an example of _________.
substrate-level phosphorylation
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 TCA cycle generates all of the following from each acetyl-CoA molecule oxidized except _________.
two ATP or GTP molecules
During breakdown of fatty acids, carbons are removed __________ at a time with each turn of the cycle, and two carbon units are released as __________.
two; acetyl-CoA
Which of the following are consequences of anaerobic respiration? (Check all that apply.)
Some bacteria are able to readily survive in both well-oxygenated as well as anoxic environments. Some bacteria may cause denitrification. Bacteria are able to reduce the levels of NO3− in sewage plant effluents.
How is ATP produced during fermentation?
Substrate-level phosphorylation
Differences between mitochondrial and E. coli electron transport chains include which of the following?
The E. coli chain contains a different array of cytochromes.
In order for a substance to transfer a phosphate to ADP in a substrate-level phosphorylation reaction, which of the following must be true?
The phosphate donor must have a higher phosphate transfer potential than ATP.
What distinguishing feature characterizes aerobic and anaerobic respiration but does not play a role in fermentation pathways?
The presence of an electron transport chain
Which of the following is NOT true regarding ATP synthases?
The proton flow is outward during ATP synthesis.
