Flashcards in Microbial Metabolism  Deck (41):
Due to the number of phosphate groups, ATP has approximately three times more energy stored than AMP, and ADP has approximately two-thirds the energy stored of ATP.
The Embden-Meyerhof-Parnas pathway is another name for
A the citric acid cycle.
B electron transport.
C NADH production.
Which of the following is a common energy storage polymer in microorganisms?
B adenosine triphosphate
From the standpoint of the microorganism, in glycolysis the crucial product is
A ethanol or lactate; ATP is a waste product.
B ATP; the fermentation products are waste products.
C CO2; ATP is a waste product.
D not relevant because glycolysis is not a major pathway.
Why is ATP required for glycolysis?
A ATP is used to reduce NAD+ to NADH.
B ATP is used to convert PEP into pyruvic acid.
C ATP is used to convert DHAP into G3P.
D ATP makes it easier to break apart glucose into two three-carbon molecules.
How many net ATPs can be made from one molecule of glucose in glycolysis?
What carbon molecules remain at the end of glycolysis?
A Pyruvic acid
B Glyceraldehyde 3-phosphate (G3P)
D Dihydroxyacetone phosphate (DHAP)
Which of the following statements about glycolysis is true?
A All cells perform glycolysis.
B Glycolysis is also called the Embden-Meyerhof pathway.
C Glycolysis is the main source of NADH in the cell.
D Glycolysis produces glucose.
Glycolysis produces energy in which form?
A Pyruvic acid
C NADH and ATP
E NADH, ATP, and pyruvic acid
Which step is the step for which glycolysis is named?
What is meant by substrate-level phosphorylation?
A Reduction of NAD+ to NADH
B Production of ATP using energy from a proton gradient
C Splitting of glucose into two pyruvic acid molecules
D Production of ATP by transferring phosphates directly from metabolic products to ADP
What is the driving force of energy production in steps 6 and 7?
A The energy potential of a proton gradient
B The reduction of three-carbon compounds
C The oxidation of three-carbon compounds
D The reduction of NAD+ to NADH
Electron carriers used in electron transport chains are always found in membranes. Which one of the following statements is NOT a reason why electron transport chains are found in membranes?
A So that electron-only carriers can be arranged to alternate with electron-plus-proton carriers in the chain.
B so that they can transport NADH out of the cell to the periplasm
C so that the electron carriers can be oriented within the membrane such that protons are passed from one side of the membrane to the other
D so that they can efficiently pass electrons in sequence from the carriers with the more negative reduction potentials to those with the more positive reduction potentials
During electron transport reactions,
A OH- accumulates on the inside of the membrane while H+ accumulates on the outside.
B both OH- and H+ accumulate on the outside of the membrane.
C OH- accumulates on the outside of the membrane while H+ accumulates on the inside.
D both OH- and H+ accumulate on the inside of the membrane.
How does the proton motive force lead to production of ATP?
A Translocation of three to four protons drives the F0 component of ATPase which in turn phosphorylates one ADP into ATP.
B ATPase requires one proton to make one ATP.
C Protons must be pumped against a concentration gradient from outside of the cell into the cell to rotate the F0 subunit of ATPase for the F1 subunit to make ATP.
D Oxidative phosphorylation of ADP by ATP synthase requires protons as cofactors in the reaction.
The proton motive force (PMF) is driven by __________.
A the difference in charge across the plasma membrane with protons outside the membrane
B the pumping of electrons though the plasma membrane
C the difference in charge across the plasma membrane with electrons outside the membrane
D the pumping of protons through the plasma membrane
The proton motive force is most often generated by splitting of H2.
In electron transport systems, the electron carriers are membrane associated.
The net result of electron transport is the generation of a pH gradient and an electrochemical potential across the membrane.
Why does lack of oxygen result in the halt of ATP synthesis?
A It causes one of the cytochromes in the electron transport chain to be permanently stuck in the reduced state.
B The chain shuts down and can no longer pump hydrogen ions across the membrane, and the proton gradient cannot be maintained.
C Oxygen prevents uncoupling of the electron transport chain.
Why might some cells uncouple the electron transport chain?
A Cells can use the energy from the proton gradient for functions other than producing ATP, such as heat generation.
B Too much ATP is bad for the cell.
C Uncoupling proteins offset the effect of cyanide.
D A cell does not require ATP.
How does cyanide poisoning result in the decrease of ATP production?
A Cyanide uncouples the proton gradient from the process of ATP synthesis.
B Cyanide permanently reduces cytochrome a3, preventing other components to change into the oxidized state. This causes the proton gradient to break down, stopping ATP synthesis.
C Cyanide permanently binds to oxygen, preventing its use as the final electron acceptor.
D Cyanide permanently oxidizes cytochrome a3, preventing other components to change into the reduced state. This causes the proton gradient to break down, stopping ATP synthesis.
Which of the following situations does not result in a breakdown of the proton gradient?
A Oxygen deprivation
B Uncoupling proteins
C Cyanide poisoning
According to the animation, which compounds provide electrons to the system?
A NADH and FADH2
The process of generating ATP using a proton gradient is referred to as
A the electron transport chain.
B water damming.
Why does FADH2 yield less ATP than NADH?
A FADH2 electrons enter the electron transport chain at a lower energy level.
B Electrons from FADH2 cannot pump hydrogen ions out of the cell.
C FADH2 binds directly to the ATP synthase enzyme.
D FADH2 electrons ultimately do not go to oxygen.
Which of the following can be used as a final electron acceptor for aerobic respiration?
A Molecular oxygen
B Carbonate ion
C Nitrate ion
D Nitrate ion, sulfate ion and carbonate ion can all be used as a final electron acceptor.
What is one difference between ubiquinones and cytochromes?
A Ubiquinones can only be reduced; cytochromes can only be oxidized.
B Ubiquinones are not made of protein; cytochromes are.
C Ubiquinones cannot carry electrons; cytochromes can.
D Ubiquinones can only be oxidized; cytochromes can only be reduced.
Iron is considered an essential element for many bacteria. Based on the animation, how would lack of iron affect energy production of a bacterium?
A Lack of iron would mean that most of the oxygen could be reduced to form water, improving energy yields.
B Lack of iron would mean lack of heme, and thus lower amounts of functioning cytochrome proteins. This would mean lower energy yields.
C Lack of iron would not have any affect on this system.
Which intermediate compound(s) in the citric acid cycle is/are often used for biosynthetic pathways as well as carbon catabolism?
A α-ketoglutarate, oxaloacetate, and succinyl-CoA
Microbial growth on the two-carbon acetate substrate invokes
A the citric acid cycle for aerobic catabolism.
B the glyoxylate and glycolysis pathways.
C the glyoxylate pathway.
D both the citric acid and glyoxylate pathways.
glyoxylate, is the TCA cycle used by some microbes, minus the steps where CO2 is lost, allows fats to become glucose
If the citric acid cycle was interrupted after the reaction that forms citrate, predict how this would affect the total amount of ATP generated per glucose molecule.
A The amount of ATP would be reduced from a total of 38 ATP to 8 ATP.
B The amount of ATP would be reduced from a total of 38 ATP to 22 ATP.
C The amount of ATP would be reduced from a total of 38 ATP to 30 ATP.
D The amount of ATP would be reduced from a total of 38 ATP to 14 ATP.
Regeneration of oxaloacetate is essential for the citric acid cycle to be cyclical.
What occurs at the bridge step?
A Decarboxylation of pyruvic acid
B The formation of oxaloacetate
C The production of GTP
D The formation of succinyl CoA
Based on the animation, how many electron carriers are reduced in the Krebs cycle only?
What is the fate of metabolites during respiration?
A They are rearranged to form GTP.
B They are reduced to from NADH and FADH2.
C They are oxidized completely to carbon dioxide and water.
D They are oxidized completely to form pyruvic acid.
Which of the following is needed as a reactant for the first step of the citric acid cycle?
A Oxaloacetic acid
B Succinyl CoA
C Malic acid
D Citric acid
Where does the energy come from to power the formation of GTP?
B Succinyl CoA
Which step involves the release of carbon dioxide?
A The third and fourth steps
B The first and eighth steps
C The second step
D The seventh step
How many molecules of ATP can be generated from one molecule of NADH?