AP Biology
John D. O’Bryant School of
Mathematics and Science
September 27, 2012
AP Biology
Agenda
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HW discussion
Build-A-Membrane
Osmosis Jones
Lorenzo’s Oil
AP Biology
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 1. Who proposed that membranes are a
phospholipid bilayer between two layers of
hydrophilic proteins?
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A) H. Davson and J. Danielli
B) I. Langmuir
C) C. Overton
D) S. Singer and G. Nicolson
E) E. Gorter and F. Grendel
AP Biology
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 2. Who proposed that the membrane is a mosaic
of protein molecules bobbing in a fluid bilayer of
phospholipids?
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A) H. Davson and J. Danielli
B) I. Langmuir
C) C. Overton
D) S. Singer and G. Nicholson
E) E. Gorter and F. Grendel
AP Biology
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 3. Which of the following is one of the ways that the
membranes of winter wheat are able to remain fluid
when it is extremely cold?
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A) by increasing the percentage of unsaturated
phospholipids in the membrane
B) by increasing the percentage of cholesterol
molecules in the membrane
C) by decreasing the number of hydrophobic proteins
in the membrane
D) by co-transport of glucose and hydrogen
E) by using active transport
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 4. Which of the following would likely move
through the lipid bilayer of a plasma membrane
most rapidly?
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A) CO2
B) an amino acid
C) glucose
D) K+
E) starch
AP Biology
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 Five dialysis bags, constructed from a semi-permeable
membrane that is impermeable to sucrose, were filled with
various concentrations of sucrose and then placed in
separate beakers containing an initial concentration of 0.6
M sucrose solution. At 10-minute intervals, the bags were
massed (weighed) and the percent change in mass of each
bag was graphed.
AP Biology
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 5. Which line represents the bag that contained a
solution isotonic to the 0.6 molar solution at the
beginning of the experiment?
 6. Which line represents the bag with the highest initial
concentration of sucrose?
 7. Which line or lines represent(s) bags that contain a
solution that is hypertonic at the end of 60 minutes?
AP Biology
Build-A-Membrane
AP Biology
Lorenzo’s Oil
AP Biology