Exam 5: Membrane Transport and Cell Signaling

Use this description to answer the following question. A major group of G-protein-coupled receptors contains seven transmembrane α helices. The amino end of the protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on the cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others. -Lipid-soluble signaling molecules, such as testosterone, cross the membranes of all cells but affect only target cells because

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?

In receptor-mediated endocytosis, receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis?

The function of phosphatases in signal transduction is best described as to

Figure 5.5 The following questions are based on Figure 5.5. -Cystic fibrosis is a genetic disease in humans in which the CFTR protein, which functions as a chloride ion channel, is missing or nonfunctional in cell membranes. The CFTR protein belongs to what category of membrane proteins?

Water passes quickly through cell membranes because

In order for a protein to be an integral membrane protein it would have to be

Use this description to answer the following question. A major group of G-protein-coupled receptors contains seven transmembrane α helices. The amino end of the protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on the cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others. -Based on the figure given below, which of these experimental treatments would increase the rate of sucrose transport into the cell?

Use this description to answer the following question. A major group of G-protein-coupled receptors contains seven transmembrane α helices. The amino end of the protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on the cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others. -The coupled G protein most likely interacts with this receptor