A selectively-permeable biological membrane that separates the interior of all cells from the outside environment.

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Blebbistatin effect on vesicles

Blebbistatin is a drug that specifically inhibits the assembly of myosin in the cytoskeleton. What effect would you expect blebbistatin to have on intracellular vesicles? ...
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14 views

What are the secondary structure requirements for cell-penetrating peptides AKA protein transduction domains

Some background: Cell penetrating peptides (CPPs) are a class of short amino acid sequences which are sufficient for crossing cell membranes and delivering themselves along with any attached cargo ...
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101 views

Why don't surfactants destroy or incorporate into cell membranes?

How do surfactants remain on the surface of pneumocytes without (1) acting as a detergent or (2) the phospholipids getting incorporated into the membranes of pneumocytes... I'm guessing the answer ...
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109 views

What would happen if a cell is poked by a fine needle?

I had seen this question in an exam: A living cell has a protoplasm which is water based and demarcated by a lipid bilayer membrane. If a cell is pierced to 1/5th of its diameter with a very sharp ...
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32 views

What are all of the currently known variations of the G zipper motif?

The G zipper motif is found in transmembrane proteins at an above random frequency and there are models explaining how it might help with multiple transmembrane intra-membrane helix bundle assembly. ...
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43 views

charges on the cell membrane

I know that there are flipases and flopases that facilitate this sort of thing, but i'm curious about other possible influences. Can donnan effect be reversed so that phospholipids follow ions. For ...
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22 views

Effect of increasing Extracellular Na+ Concentration on resting voltage and likelihood of an action potential of occuring

If you increase the extracellular Na+ concentration how will this effect the resting voltage and likelihood that an action potential of will occur? Please explain using the Goldman–Hodgkin–Katz ...
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39 views

Mechanism of Octoxynol-10 as a preservative in vaccines

I noticed that the Fluarix Quad flu shot this season contains Octoxynol-10 rather than Thimerosal as a preservative. I am not expert in this area, so I did a Google search of "Octoxynol-10", and ...
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18 views

Differential Scanning Calorimetry for bacterial membranes

I would like to study the freezing and melting of bacterial membranes and would like to use Differential Scanning Calorimetry (DSC) to obtain the glass transition temperature of the membrane. However, ...
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13 views

Amount of Na+ needed to be transfered in order to depolarize the membrane?

I found out that the number of $Na^+$ ions that is needed to be transfered across the membrane to make it depolarized is a small number. In what way its proved? (Goldman equation maybe?)
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10 views

Are receptors integral membrane proteins or peripheral membrane proteins?

In tegral membranes serve as transporters. Peripheral protiens serve as cell adhesion molecules, antigens and enzymes. So what about receptors? Which protiens carry out the duty of receptors?
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19 views

Mitochodrial osmotic flux

If you incubate mitochondria in isosmotic solution of Tris/EGTA and KCH3COO solution with rotenone, no swelling occurs at first - i.e. no ions enter the matrix so water doesn't follow to compensate ...
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13 views

Cellular concentractions, why do they remain constant?

The GHK equation indicates that at its resting potential there is no net current flowing into or out of the cell. However, if we consider the current due to just one ion, then this will be none-zero ...
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48 views

Rate of potassium/sodium transport

Assume that the plasma membrane of a cell was suddenly permeable to the same degree to both Na+ and K+ and that each responded to a concentration gradient of the same magnitude. Would you expect these ...