Proteins run on SDS-PAGE gels are separated based on their size (mass) because SDS maintains intrinsic charge and beta-mercaptoethanol preserves three-dimensional structure.

You are in a lab that specializes in microscopy and you are studying breast cancer. Which microscopy technique would you use to perform the following experiments? For each experiment select the best possible technique from the drop-down menu. Use each technique only once. 

Symports and antiports always move one solute downhill (along its concentration gradient) and a second solute uphill (against its concentration gradient).

Using Fluorescence Recovery After Photobleaching (FRAP), you are studying the behavior of a membrane protein in red blood cells. Which FRAP graph would you expect to obtain if your protein is tethered/anchored to junctional complexes in the cortical cytoskeleton?  

There are three exams each worth 75 points.  Together these three exams count for _________ of my grade.

Membrane-associated proteins are embedded in the lipid bilayer through transmembrane alpha helices.

An antiport can be transformed into symport if the orientation of the transporter in the membrane is reversed (i.e. if the portion of the molecule normally exposed to the cytosol faces the outside of the cell instead).

You have identified a novel protein complex that forms a pore across the plasma membrane of a eukaryotic cell. The pore is made of five protein subunits, each of which contributes a membrane-spanning a helix to form the pore. Each a helix has hydrophilic amino acid side chains on one face of the helix and hydrophobic amino acid side chains on the opposite side.What is the likely arrangement of these five a helices in the membrane?

It is acceptable to plagiarize answers to problem set questions.

All membrane transporters carry out active transport.