#2. Nelson 7.3 which is the following: You are trying to make artificial blood cells. You have
managed to get pure lipid bilayers to form spherical bags of radius 10um, filled with
hemoglobin. The first time you did this, you transferred the \"cells\" into pure water and they
promptly burst, spilling the contents. Eventually you found that transferring them to a 1 mM salt
solution prevents bursting, leaving the \"cells\" spherical and full of hemoglobin and water when
you try this? solution electrically conducting. How many moles per liter of glucose should you a.
If 1 mM is good, then would 2 mM be twice as good? What happens b. Later you decide that you
don\'t want salt outside because it makes younr use instead?
Solution
Answer:
2. (a) No, 2 mM wouldn\'t be twice as good. We want the cells to be in equilibrium with the
environment, meaning that the osmotic pressure would be the same on both sides of the cells. If
the environment were 2 mM, water would seep out of the cell until it reduced to half its original
volume.
(b) What matters for osmotic pressure is the number density, not the nature of the solute.
However, salt at 1 mM has twice the concentration of solute as sugar at 1 mM because salt
dissociates into two ions, so we want 2 mM sugar.
managed to get pure lipid bilayers to form spherical bags of radius 10um, filled with
hemoglobin. The first time you did this, you transferred the \"cells\" into pure water and they
promptly burst, spilling the contents. Eventually you found that transferring them to a 1 mM salt
solution prevents bursting, leaving the \"cells\" spherical and full of hemoglobin and water when
you try this? solution electrically conducting. How many moles per liter of glucose should you a.
If 1 mM is good, then would 2 mM be twice as good? What happens b. Later you decide that you
don\'t want salt outside because it makes younr use instead?
Solution
Answer:
2. (a) No, 2 mM wouldn\'t be twice as good. We want the cells to be in equilibrium with the
environment, meaning that the osmotic pressure would be the same on both sides of the cells. If
the environment were 2 mM, water would seep out of the cell until it reduced to half its original
volume.
(b) What matters for osmotic pressure is the number density, not the nature of the solute.
However, salt at 1 mM has twice the concentration of solute as sugar at 1 mM because salt
dissociates into two ions, so we want 2 mM sugar.
