(3 points) Why do cells not have membrane transport proteins for O2?  

(3 points) In which of the following cases is energy NOT needed for transmembrane transport?

(3 points) The major ATP-powered pump responsible for maintaining ion gradients across the plasma membrane of mammalian cells is:

3.5 Qu’est-ce qu’elle a fait le weekend dernier? (1)

(3 points) The lateral diffusion of a plasma membrane protein has been studied using the fluorescence recovery after photobleaching (FRAP) technique in a cell under normal conditions, and the following plot has been obtained. Under a different condition, membrane protein complexes disassemble freeing partially-immobilized protein components. As a result, its lateral diffusion coefficient is increased. How would you expect the FRAP curve to change under these new conditions? The dotted line in each graph is the original curve shown for comparison.

(3 points) Which of the following conditions results in the fastest FRAP?

(3 points) Which of the following statements about a plot of V0 vs. [S] for transport that follows Michaelis-Menten kinetics is false?   

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below. Not all words or phrases will be used; use each word or phrase only once. (7 points) The specialized functions of different membranes are largely determined by the ____[1]_________ they contain. Membrane lipids are ___[2]____________ molecules, composed of a hydrophilic portion and a hydrophobic portion. All cell membranes have the same ______[3]__________ structure, with the _______[4]_________ of the phospholipids facing into the interior of the membrane and the ___[5]___________ on the outside. The most common lipids in most cell membranes are the _______[6]________. The head group of a glycolipid is composed of ____[7]___________.   amphipathic                              hydrophobic                                 phosphatidylserine cholesterol                                 lipid bilayer                                   phospholipids fatty acid tails                           lipid monolayer                           proteins glycolipids                                   lipids                                                 sterols hydrophilic head groups    phosphatidylcholine                sugars

(3 points) Why do cells not have membrane transport proteins for O2?  

    (3 points) Proteins extracted from control cells, cells treated with trypsin, and permeabilized cells treated with trypsin are examined using SDS- Polyacrylamide Gel Electrophoresis (SDS-PAGE). Based on the analysis of the SDS PAGE studies, scientists concluded that: