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1. In each of the following examples decide in the direction of the flow, then deduce the
water p
potential and the water mass flow in kg/s.
Example 1: Glucose is a monosaccharide and sucrose (table sugar) is a disaccharide.
Example 2: Same solutes as in Example 1, but their concentrations are presented differently.
Example 3: NaCl or sodium chloride is, of course, table salt. Before doing the problem,
think about what happens to salt when it is dissolved in water.
Example 4: Albumin is the most abundant protein in blood. Glycine is an amino acid assume
that it is not a salt.
Example 5: Insulin is a small protein hormone that is critical for maintaining normal blood
glucose concentrations.
Example 6: KCl or potassium chloride is an inorganic salt. For the first time, we see
a mixture
of solutes in the right compartment.
2. Introducing the spherical capacitor model to simulate the ordinary living cell,
i) determine the electrostatic field across the cell wall if the potential difference
between the inside and the outside of the cell was measured to be Vab =-90 mV
and the cell wall is 0.1μm. What is the work done against the electrostatic force to
transfer a single electron from the outside to the inside of the cell?
ii) calculate the energy density in J/cm3 wasted by the living cell to pump out
sodium ions of concentration 145 μM/cm3 across its membrane potential barrier (90mV).
iii) find the capacitane per unit area of the cell membrane
iv) estimate the total energy wasted per cm3 if the sodium pumping consumes about
20%
of the total energy exerted by the body cells during rest. (1 μM =10-6*6.0223*1023).
Example 1: Glucose is a monosaccharide and sucrose (table sugar) is a
disaccharide.
Example 2: Same solutes as in Example 1, but their concentrations are presented
differently.
Example 3: NaCl or sodium chloride is, of course, table salt. Before doing the
problem, think about what happens to salt when it is dissolved in water.
Example 4: Albumin is the most abundant protein in blood. Glycine is an amino
acid - assume that it is not a salt.
Example 5: Insulin is a small protein hormone that is critical for maintaining
normal blood glucose concentrations.
Example 6: KCl or potassium chloride is an inorganic salt. For the first time, we
see a mixture of solutes in the right compartment.