BIO 1510 - CH 7
One way to generate acetyl-CoA is to convert pyruvate into acetyl-CoA by stripping off aCO2 molecule. The removal of CO2 is referred to as what type of reaction?A) DecarboxylationB) GlycolyticC) CarboxylationD) Acetylation
A
Organisms that can manufacture their own chemical energy are called_________.A) autotrophsB) heterotrophsC) oligotrophsD) chemotrophs
A
This process is common to all living cells:A) GlycolysisB) Alcohol fermentationC) The Citric acid cycleD) Electron transport chain reactionsE) Pyruvate oxidation
A
What aspect of cellular respiration occurs in the cytoplasm in eukaryotic cells?A) GlycolysisB) Pyruvate oxidationC) The Citric acid cycleD) The electron transport chainE) ATP synthesis
A
What molecule can oxidize NADH?A) AcetaldehydeB) LactateC) UbiquinoneD) Glucose
A
Why are the components of the electron transport chain embedded in the inner mitochondrialmembrane rather than floating freely in the cytoplasm of the mitochondrial matrix?A) To generate and maintain the proton gradient essential for ATP production.B) To separate the ATP from the ADP. ) Because electrons cannot float in the matrix.D) Because NADH cannot localize to the mitochondrial matrix.
A
A human cell has a mutation in the gene that encodes the enzyme that generates lactate frompyruvate, rendering that enzyme completely non-functional. Assuming that there is ampleglucose present, how would this cell generate energy in the presence of oxygen?A) Glycolysis coupled with ethanol fermentationB) Aerobic respirationC) Primarily through the breakdown of proteins into amino acidsD) This cell would have no way to generate energy under these conditions because itcannot carry out the reactions needed for glycolysis
B
Glucose is not our only food source, nor the only one we can utilize in our bodies to generateenergy. Other primary sources of energy include other sugars, proteins, and fats. Whatmetabolic intermediate are fats primarily converted into?A) PyruvateB) Acetyl-CoAC) Citric acid cycle intermediatesD) Electron transport chain componentsE) ATP Synthase
B
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 oxygenvia fermentation.B) No, oxygen is a required cofactor for the complexes in the electron transport chain.C) Yes, if a cell can use a terminal electron acceptor other than oxygen, it can make useof the electron transport chain.D) No, oxygen is the primary electron acceptor in electron transport chains in all celltypes.
C
In the reaction catalyzed by aconitase, the conversion of citrate to isocitrate is inhibited byfluoroacetate. Fluoroacetate is used as a pesticide. Why is this an effective pesticide?A) It inhibits glycolysisB) It inhibits pyruvate oxidationC) It inhibits the Citric acid cycleD) It inhibits the electron transport chainE) It inhibits ATP synthase
C
Regardless of the electron or hydrogen acceptor used, one of the products of fermentation isalwaysA) ADP.B) ATP.C) NAD+.D) pyruvate.E) alcohol.
C
To form NADH from NAD+, two electrons and a proton are removed from an organicmolecule. What term best describes the reaction in which electrons and a proton are removedfrom an organic molecule?A) CondensationB) ReductionC) DehydrogenationD) DecarboxylationE) Isomerization
C
What is common to all of the oxidation reactions in the Citric acid 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 tothe reduction of an electron acceptor.D) They all lead to substrate-level phosphorylation of ADP to generate ATP
C
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 sulfurbacteria living in your pipes. What molecule do these bacteria use as an electron acceptor?A) O2B) H2OC) SO4D) H2S
C
As a forensic pathologist, you have just completed an autopsy of a poisoning victim. After athorough examination, you conclude that the victim died of cyanide poisoning. You knowthat cyanide binds to the cytochrome oxidase complex, and therefore list the official cause ofdeath as suffocation due to cyanide exposure. However, if you wanted to provide a moretechnical explanation as to the cause of death, which process was specifically inhibiteddirectly by cyanide?A) The reduction of NAD+B) The oxidation of FADH2C) All proton pumping into the intermembrane spaceD) The formation of water from oxygenE) ATP synthesis
D
Cardiac muscle cells need to generate significant amounts of ATP to allow for constantcontractile activity. As a result, they primarily depend upon beta-oxidation of fatty acids,which has a higher energy yield than the catabolism of glucose. What would be the ATPyield for beta-oxidation of a hypothetical 10-carbon fatty acid?A) 32 ATPB) 35 ATPC) 50 ATPD) 62 ATPE) 65 ATP
D
If you take into account the amount of ATP generated by ATP synthase per molecule ofNADH and per molecule of FADH2 produced, and the number of ATP molecules producedby substrate-level phosphorylation, what is the predicted energy yield of the Citric acid cycle,per molecule of glucose in eukaryotic cells?A) 18 ATPB) 2 ATPC) 10 ATPD) 20 ATPE) 30 ATP
D
In glycolysis, a major portion of the energy remains in the final product, which is calledA) glucose.B) citrate.C) glyceraldehyde 3-phosphate (G3P).D) pyruvate
D
In order to lose weight and reduce body fat, a friend of yours has decided to eliminate all fatfrom his diet, while consuming unrestricted amounts of carbohydrates. What do you think ofthis idea?A) It is a good idea, because if your friend doesn't eat any fat, he cannot store anyadditional fat.B) It is a bad idea, because consumption of fat is required to provide cofactors for theelectron transport chain.C) It is a good idea, because under conditions where ATP levels are low in cells,carbohydrates will be stored, and fat stores will be catabolized via beta-oxidation togenerate energy.D) It is a bad idea, because if ATP levels are high in cells, excess acetyl-CoA from themetabolism of carbohydrates can be used for fatty acid synthesis.
D
It is thought that the oldest stage of cellular respiration from an evolutionary perspective isA) the Citric acid cycle.B) the electron transport chain.C) fermentation.D) glycolysis
D
Pyruvate oxidation in eukaryotic cells occurs in the _________.A) cytoplasmB) nucleusC) Golgi bodyD) mitochondriaE) plasma membrane
D
The energy released in the mitochondrial electron transport chain is used to transport protonsinto theA) mitochondrial matrix.B) cytoplasm.C) endoplasmic reticulum.D) intermembrane space of the mitochondria.E) nucleus
D
What happens to the oxygen that is used in cellular respiration?A) It is converted to carbon dioxideB) It is used to make glucoseC) It is used to make Citric acid cycle intermediatesD) It is reduced to form waterE) It is converted to acetyl-CoA
D
What is the oxidized form of the most common electron carrier that is needed for bothglycolysis and the Citric acid cycle?A) ATPB) FADC) pyruvateD) NAD+E) acetyl-CoA
D
What must happen to amino acids before they can be used in catabolic reactions?A) They must be decarboxylatedB) They must be deoxygenatedC) They must be dehydrogenatedD) They must be deaminated
D
Your friend is having difficulty keeping track of the energy flow from glucose throughglycolysis, the Citric acid cycle and electron transport. Your best advice would be toA) follow ATP production.B) follow the protons.C) follow NAD+ production.D) follow the electrons.
D
The equation for cellular respiration is C6H12O6 + 6O2 → 6CO2 + 6H2O. At what specificpoint 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 glycolysisB) During the oxidation and ATP formation reactions in glycolysisC) During pyruvate oxidationD) During the condensation reaction (actetyl CoA + oxaloacetate) in the Citric acid cycleE) During the second oxidation in the Citric acid cycle
E
What is an end-product of glycolysis?A) OxaloacetateB) NAD+C) AlcoholD) ADP E) PYRUVATE
E
When amino acids are degraded in cells, into what intermediate(s) of the aerobic respirationprocess are the carbon skeletons of amino acids primarily converted?A) PyruvateB) Acetyl-CoAC) Citric acid cycle intermediatesD) Pyruvate and acetyl-CoAE) Pyruvate and Citric acid cycle intermediates
E
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 mitochondrialmembrane.D) osmosis of macromolecules.E) large quantities of ADP.
C
If citrate levels are high in the cell, but ATP levels are low, what do you think will happen inthe cell?A) In the presence of glucose, glycolysis will run to generate energy for the cell, but theCitric acid cycle will be inhibited. ) Glycolysis will be inhibited, but the Citric acid cycle will be functional, allowing it tobe utilized to breakdown acetyl-CoA generated from beta-oxidation.C) The electron transport chain will be inhibited, causing a build-up of NADH andFADH2. This will inhibit the Citric acid cycle, but in the presence of glucose,glycolysis will still run coupled with fermentation to regenerate NAD+.D) Glycolysis and the Citric acid cycle will both be inhibited, thus under these conditionsthere will be no mechanism to generate ATP.
B
If you take into account the amount of ATP generated by ATP synthase per molecule ofNADH produced in aerobic respiration, the net number of ATP molecules produced bysubstrate-level phosphorylation, and the fact that NADH molecules produced in thecytoplasm have to be transported into the mitochondria, what is the predicted energy yield ofglycolysis in eukaryotic cells?A) 2 ATPB) 5 ATPC) 7 ATPD) 32 ATPE) 30 ATP
B
Organisms that depend on the energy stored in chemical bonds by other organisms for theirfood energy are called_________.A) AutotrophsB) HeterotrophsC) OligotrophsD) Chemotrophs
B
Phosphofructokinase is regulated by a number of factors, including high levels of ATP. Whyis this enzyme regulated by ATP levels?A) If ATP levels are high, this provides a mechanism to directly inhibit the Citric acidcycle, thus preventing further generation of NADH, FADH2 and ATP molecules thatare not needed.B) If ATP levels are high, it is important to directly inhibit the reaction that commits thesubstrate to glycolysis to allow the substrate to be available for other reactions, sincethe cell has ample energy.C) If ATP levels are high, it is important to inhibit ATP synthase, andphosphofructokinase directly inhibits ATP synthase.D) If ATP levels are high, this provides a mechanism to directly inhibit the electrontransport chain, thus preventing the formation of a proton gradient in theintermembrane space of mitochondria.
B
What are the products of one turn of the Citric acid cycle?A) 1 CO2, 2 NADH, 1 FADH2, 1 ATPB) 2 CO2, 3 NADH, 1 FADH2, 1 ATPC) 2 CO2, 6 NADH, 2 FADH2, 2 ATPD) 4 CO2, 6 NADH, 2 FADH2, 2 ATPE) 4 CO2, 12 NADH, 4 FADH2, 4 ATP
B
What is different about the way that NADH and FADH2 donate electrons to the electrontransport chain?A) NADH is oxidized and FADH2 is reduced.B) NADH contributes its electrons to the first transmembrane complex in the electrontransport chain and FADH2 contributes its electrons after the first transmembranecomplex.C) More protons are transported into the intermembrane space of the mitochondria inresponse to one molecule of FADH2 as compared to the number of protonstransported 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.
B
What stage of cellular respiration can occur in human cells with or without oxygen present?A) The Citric acid cycleB) GlycolysisC) The electron transport chainD) Pyruvate oxidation
B
What would be the ATP yield for a molecule that is catabolized to form one molecule ofpyruvate in a eukaryotic cell?A) 10 ATPB) 12.5 ATPC) 25 ATPD) 30 ATPE) 11.5 ATP
B
Aerobic respiration involves the transfer of several electrons from glucose to electron carrierssuch as NAD+ over a series of steps, and ultimately glucose reacting with oxygen to generatecarbon dioxide, water, and energy. Why does glucose not react directly with oxygen in cells?A) Oxygen cannot accept electrons, and thus an electron carrier like NAD+ is needed.B) Oxygen and glucose are localized in different subcellular compartments.C) The direct reaction of oxygen with glucose would be extremely destructive to cells.D) The reaction of oxygen with glucose is not spontaneous.
C
All of the reactions of cellular respiration that occur after glycolysis take place in what partof the eukaryotic cell?A) The chloroplastB) The nucleusC) The mitochondriaD) The plasma membraneE) The cytoplasm
C
Cytochromes contain a heme group similar to that in hemoglobin. The iron atom (Fe) in thecenter of the group can be oxidized and reduced. If someone was suffering from irondeficiency anemia, what stage of cellular respiration would be most affected?A) GlycolysisB) The Citric acid cycleC) The electron transport chainD) Fermentation
C
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 andis used to drive exergonic reactions in the cell. C) ATP can be made by direct phosphorylation of ADP in the cytoplasm, and by anenzyme complex that uses the energy from a proton gradient to drive ATP synthesisin the mitochondria. It can also be made in other locations in the cell, depending onthe cell type.D) ATP can be made by an enzyme complex that uses the energy of protons movingdown their concentration gradient from the mitochondrial matrix to the cytoplasm tomake the ATP
C
How many oxidation reactions occur during the Citric acid cycle?A) 1B) 2C) 4D) 6E) 9
C
If ATP synthase had a mutation in the F1 complex portion of the protein, which function ofATP synthase would most likely be affected?A) The rotation of the rotorB) The flow of protons through the channelC) The conversion of ADP and Pi to ATPD) The insertion of the enzyme into the membrane
C
