a) Decreased surface potential
b) Increased Surface potential
c) Decreased Dipole moment
d) Zero Dipole moment.
Answer : ? B
This article I found might throw some light.
"Solution pH Alters Mechanical and Electrical Properties of Phosphatidylcholine Membranes: Relation between Interfacial Electrostatics, Intramembrane Potential, and Bending Elasticity"
Biophys J. 2007 April 1; 92(7): 2451–2462.
Published online 2006 December 15. doi: 10.1529/biophysj.106.096362.
Yong Zhou and Robert M. Raphael
"the membrane dipole potential increases as solution pH decreases"
which should rule out the last two options.
Now read this ---------
"At pH 2 and 3, SOPC vesicles have a positive ζ-potential, indicating extensive association of protons at the membrane surface. This agrees with other investigations demonstrating that phospholipids carry a positive ζ-potential at low pHs . At pH 4, the ζ-potential is nearly zero (∼3.5 mV) and the LUVs showed low mobility, in agreement with other investigations demonstrating that the isoelectric point of PC lipids is ∼pH 4 . At the near neutral pH of 6.5, the ζ-potential is clearly negative (∼−21 mV), in agreement with many investigations which have pointed out that PC is negatively charged between −10 mV and −30 mV at neutral pH"
-------------------
Therefore the answer might be (B). Increased Surface Potential
Yong Zhou and Robert M. Raphael
"the membrane dipole potential increases as solution pH decreases"
which should rule out the last two options.
Now read this ---------
"At pH 2 and 3, SOPC vesicles have a positive ζ-potential, indicating extensive association of protons at the membrane surface. This agrees with other investigations demonstrating that phospholipids carry a positive ζ-potential at low pHs . At pH 4, the ζ-potential is nearly zero (∼3.5 mV) and the LUVs showed low mobility, in agreement with other investigations demonstrating that the isoelectric point of PC lipids is ∼pH 4 . At the near neutral pH of 6.5, the ζ-potential is clearly negative (∼−21 mV), in agreement with many investigations which have pointed out that PC is negatively charged between −10 mV and −30 mV at neutral pH"
-------------------
Therefore the answer might be (B). Increased Surface Potential
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