which of the following is NOT true reguarding the resting membrane potential of a cell?
912050
I think D is incorrect.  The inside of the cell is negative compared to the outside of the cell.  Therefore, the electrical gradient of Na+ would want to move Na+ into the cell.
54079
There are numerous proteins embedded in the lipid bilayer of the cell membrane; some, like adrenergic receptors and porins (channels things move through), perforate the membrane; others protrude out one part, not another.  Others, like the G-proteins and the enzymes that phosphorlate and dephosphorylate other membrane proteins, stay pretty much entirely in the membrane.\nMany of the proteins, such as receptors and porins, move fairly freely; others, particularly the proteins that cause adherence between cells, are fixed in place.\nI guess the best answer is that the arrangement of the proteins in the cell membrane is complex, and for many proteins, ever changing, but for others, static.  It's not nearly as simple as it looks.  For instance, in modeling the large membrane proteins, the cell membrane is effectively a gas in two of three dimensions, and a solid in the third...  Go figure.
731401
Correct.\nD. when delta G is positive the reaction is non-spontaneous
518652
It is the simplest form of a cell membrane. Actually the cell on contain es the cell membrane and nothing else. It is used for research when doing tests on a cell membrane. It has nothing that could interfere with normals.
866207
the cell dividing force lol. theres no such force. it's a spontaneous occurence
1111003
a. Correct. This is a homeostatic mechanism\nb. positive feedback not negative\nc. impossible unless you are stimulated for life\nd. has nothing to do with receptor sites
905232
Diffusion thru semipermeable membrane depends on the concentration..ions will move from high concentration to low concentration.  The difference in charge (low vs. high) will cause a change in electrically voltage (mV), which will open the ion channels so the high concentration of ions will move into the low concentration.
872390
ions are polar, so they don't mix with the non-polar lipid bilayer. there are protein channels for their transportation, and pumps and all that..
817241
The correct sequence is (B).  Here's a numbered explanation:\n\nUnder normal conditions, potassium ions leak out of a cell faster than sodium ions leak in; as a result, a 'resting' cell membrane will have a negative potential.  Some stimulus may then cause a depolarization (movement toward neutral potential) in some small part of the membrane [4] -- this is the beginning of the action potential process.  Depolarization allows sodium ions to flood through the cell membrane [6], driving the membrane into positive potential [7].  At a certain point, the sodium channels shut down in response to the change in potential [1], and the flood reverses -- now potassium ions diffuse out of the cell in larger numbers [2].  Eventually, the sodium channels reach their normal state again [3].  The potassium channels also calm down, but just like the sodium ions before, they've gone too far, resulting in hyperpolarization of the membrane (or what is also called the 'undershoot,' because the potential goes more negative than its resting value) [5].
759492
All cells are semipermeable and depending on what passes into the cell, determines how the membrane responds to each substance. Glucose moves across the membrane, as do sodium and potassium.
764570
The semipermeable membrane that encloses the cytoplasm of a cell.
598126
The distribution of ions across a cell membrane produces a concentration gradient that can be used by the cell to do various kinds of work (i.e. power non-spontaneous reactions).  \n\nFor example, in mitochondria and certain aerobic bacteria, the gradient of H+ ions powers ATP synthase, and allows it to make ATP (an extremely important energy storage molecule).  \n\nIn other cells, the concentration gradients of ions can be used to facilitate active transport across the membrane by coupling an ion moving along it's concentration gradient with another molecule moving against it.\n\nIn neurons, the difference in the concentrations of ions inside and outside the cell creates a membrane polarity that allows the action potential (i.e. the nerve firing) to occur.  When the nerve is activated by a neurotransmitter or a direct external stimulus, sodium channels open, allowing Na+ to rush into the cell, making it positive relative to the external environment.  This change in polarity moves along the cell, and causes the cell to release specific neurotransmitters at the other end.\n\nIf the ions were distributed equally, none of the processes I just mentioned would work!
91184
D - it can cause hyperpolarization or depolarization of membrane
723400
Water is actually the main component of the cytoplasm of a cel, as well as being used in energy production cycles.  As a small, non-polar molecule, water enters the cell by way of passive diffusion called osmosis.  The semi-permeable membrane means that not just anything can cross it.  The only things that can passively cross the membrane are molecules that are, like water, small and non-polar.  Anything else must be actively transported in, or have a channel protein.
734307
Restore celll membrane potential, restore normal membrane transport and ionic balance.
282411
It's all to do with the action potential of the muscle cell. We have different sorts of them in our body...eg cardiac, smooth muscle..etc.
235226
It will shrivel up, as osmosis causes water to leave the cell.  Remember, hypertonic means there are more solutes in the solution than in cytoplasm.  Think of osmosis as trying to "balance" the concentration of solutes inside and outside the cell.  If it can't bring solutes into the cell, it's going to bring water out of the cell.