#Question id: 2217
#Unit 2. Cellular Organization
In immunofluorescence studies you always see the small G-protein Ras in a specific region of the cell and, given its protein sequence along with many other proteins localized to this area, you hypothesize that their C-terminal Cys-Ala-Ala-X (X can be any amino acid) motifs may be responsible for targeting these proteins to this subcellular region. To test this hypothesis, you genetically engineer the sequence encoding this motif onto a cDNA encoding green fluorescent protein. When immunofluorescence is used, where specifically would you expect to see GFP localized in the cell?
#Question id: 2218
#Unit 2. Cellular Organization
Human alkaline phosphatase protein is attached to the plasma membrane by a GPI anchor. In an experiment you treat cells with each of the following enzymes and find one of them inhibits the activity of the protein because it releases it into the extracellular matrix. Which specific enzyme led you to conclude that this anchor on alkaline phosphatase was both necessary and sufficient for binding the protein to the membrane where it can perform its normal activity?
#Question id: 2219
#Unit 2. Cellular Organization
Cholesterol and phospholipids are transported between organelles by
i. Golgi-dependent mechanisms.
ii. incompletely characterized vesicle populations.
iii. direct contact between membranes and, to some extent, small, soluble lipid-transfer proteins.
Which of the following statements are correct?
#Question id: 2220
#Unit 2. Cellular Organization
Cell membranes have distinct inside and outside faces. Which of the following statements is the most likely explanation for the membrane's asymmetrical nature?
#Question id: 2221
#Unit 2. Cellular Organization
The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.
At the beginning of the U-tube experiment illustrated above, which of the following statements is true?
#Question id: 2222
#Unit 2. Cellular Organization
The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.
In the U-tube experiment illustrated above, which of the following statements correctly describes side B at equilibrium?