Bacteria have a membrane potential, although the mechanisms of how it is maintained differ from those of mammalian cells. The transport of protons across the cell membrane is an important part of the mechanism, so a bacterium's membrane potential varies with the proton concentration the pH of the surrounding fluid. One strain of bacteria was found to have a membrane potential of -120 mV at a pH of 7.5. A bacterium can be modeled as a 1.5-um- diameter sphere. How many positive ions are needed on the exterior surface to establish this membrane potential? (There are an equal number of negative ions on the interior surface.) Assume that the membrane properties are the same as those of mammalian cells.
Bacteria have a membrane potential, although the mechanisms of how it is maintained differ from those of mammalian cells. The transport of protons across the cell membrane is an important part of the mechanism, so a bacterium's membrane potential varies with the proton concentration the pH of the surrounding fluid. One strain of bacteria was found to have a membrane potential of -120 mV at a pH of 7.5. A bacterium can be modeled as a 1.5-um- diameter sphere. How many positive ions are needed on the exterior surface to establish this membrane potential? (There are an equal number of negative ions on the interior surface.) Assume that the membrane properties are the same as those of mammalian cells.
Biochemistry
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ISBN:9781319114671
Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
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Chapter1: Biochemistry: An Evolving Science
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Transcribed Image Text:1. Bacteria have a membrane potential, although the mechanisms of how it is maintained differ
from those of mammalian cells. The transport of protons across the cell membrane is an
important part of the mechanism, so a bacterium's membrane potential varies with the proton
concentration the pH of the surrounding fluid. One strain of bacteria was found to have a
membrane potential of -120 mV at a pH of 7.5. A bacterium can be modeled as a 1.5-µm-
diameter sphere. How many positive ions are needed on the exterior surface to establish this
membrane potential? (There are an equal number of negative ions on the interior surface.)
Assume that the membrane properties are the same as those of mammalian cells.
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