Question

1. How might a liposome be prepared that could potentially be used in the treatment of a tumor whose cells have a protein called tumor cell antigen (TCA) in their membranes? This protein is missing from all normal cells.

2. You are exposing a rather inhospitable planet, which has seas that are somewhat hydrophobic in nature. Surprisingly, there are living organisms in the seas whose cytoplasm is hydrophobic to a similar degree. These organisms have membranes made primarily of phospholipids arranged in a bilayer. What is the most probable orientation of these phospholipids?

3. You are characterizing an isolated membrane protein. The protein is exposed on both sides of the membrane. Over much of the central part of its surface, there are hydrophobic amino acids, while the ends are hydrophilic. It crosses the membrane a number of times. There is an opening in the center of this protein lined by hydrophilic amino acids. What kind of protein is this and what is its probable function?

4. You are studying a transport molecule. It appears to bind temporarily to the molecule to be transported. During normal transport, no energy is expended. The addition of a particular molecule closely resembles the normally transported molecule inhibits transport. An increase in the concentration of the normally transported molecule in the presence of a constant concentration of the inhibitor increases the rate of transport. What kind of transport is described and what is the inhibiting molecule?

Answer 1