Answer four of five discussion questions, or all five for up to five points extra credit. Proteins that are secreted have a special path. Describe the process of translation as it would occur for a protein that is secreted into the lumen of the endoplasmic reticulum. Include the role of signal peptides, SRP's, SRP receptors, and pores. Describe how cilia move, including the roles of tubulin, dynein, and nexin.
Microtubules go from slowly growing to rapidly shrinking.
Often one microtubule that is growing will be only nanometers away from one that is shrinking. B cells are lymphocytes that, when activated, become antibody- secreting plasma cells. One of the changes that occurs is that B cells initially have a membrane-bound form of antibody, which later turn into a secreted form. The two forms are exactly alike, except for their carboxy terminal end, which is imbedded in the membrane in the membrane bound form.