A patient has been exposed to a toxic compound that increases the permeability of the mitochondrial membranes to protons. Which of the following metabolic changes would be expected in this patient?Group of answer choicesIncreased ATP synthase activityIncreased ATP levelsIncreased oxygen utilizationDecreased electron transport in the respiratory chainAll of the above
Question
A patient has been exposed to a toxic compound that increases the permeability of the mitochondrial membranes to protons. Which of the following metabolic changes would be expected in this patient?Group of answer choicesIncreased ATP synthase activityIncreased ATP levelsIncreased oxygen utilizationDecreased electron transport in the respiratory chainAll of the above
Solution
The mitochondria is the site of ATP (adenosine triphosphate) production in cells. This process, known as oxidative phosphorylation, involves a series of reactions in which electrons are transferred from electron donors to electron acceptors such as oxygen, in reactions catalyzed by the electron transport chain. The energy from these reactions is used to pump protons across the mitochondrial membrane, creating a proton gradient.
ATP synthase, an enzyme, uses this proton gradient to generate ATP from ADP (adenosine diphosphate) and inorganic phosphate. This process is known as chemiosmosis.
If a toxic compound increases the permeability of the mitochondrial membranes to protons, the proton gradient would be disrupted. This would mean that there would be less energy available for ATP synthase to generate ATP. Therefore, ATP synthase activity and ATP levels would decrease, not increase.
Increased permeability to protons would also mean that the electron transport chain would not function as efficiently, as the energy from the electron transfer reactions would be lost as protons leak across the membrane. Therefore, electron transport in the respiratory chain would decrease.
Finally, because the electron transport chain would not be functioning as efficiently, less oxygen would be utilized in the process. Therefore, oxygen utilization would decrease.
So, the correct answer is: Decreased electron transport in the respiratory chain.
Similar Questions
Which of the following events could directly increase the pH of the mitochondrial matrix?A.Permeabilization of the inner mitochondrial membraneB.Increased electron transport chain activityC.Increased ATP synthase activityD.Inhibition of the citric acid cycle
Which of the following statements about the electron transport chain and ATP production in the mitochondria is false?Group of answer choicesAny drug that inhibits the ATP synthase will also inhibit the flow of electrons in the ETC.For oxidative phosphorylation to occur, it is essential to have a membrane that is impermeable to protons except through specific proteins pores or protein complexesThe yield of ATP per mole of fuel depends on the type of molecule being catabolized.Some complexes of the respiratory chain pump protons into the matrix to create an electrochemical gradient.Exergonic electron transfer provides the energy for proton pumping.
Which process results in the greatest amount of ATP?Group of answer choicesThe activity of the electron transport system in the Golgi apparatusThe activity of the electron transfer system in the mitochondriaKrebs cycleGlycolysis
Which of these biochemical processes would you expect to liberate the most ATP?a) Gluconeogenesisb) Fatty acid synthesisc) Glycolysisd) Beta oxidatione) Electron transport chain activity
The activity of this enzyme is the main determinant of the rate of mitochondrial fatty acid oxidation:Group of answer choicesCPTPDHHAD
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