40.A 47-year-old man presents with fatigue and over the next few years
became progressively weaker, eventually becoming paralyzed. He encoun-
ters severe problems with speech and swallowing. Weakness and paralysis
of the thoracic muscles leads to progressive respiratory insufficiency and
death. At autopsy transmission electron microscopy reveals fragmentation
of the structures delineated by the arrows within motoneurons. Which of
the following correctly characterizes these structures?
108 Anatomy, Histology, and Cell Biology
a. There is no functional, topological specialization within the stacks
b. They present an entry face associated with granule formation
c. They present a transface associated with COP-II-coated transport vesicles
d. They are biochemically compartmentalized
e. They receive proteins but not lipids
41.The primary function of intermediate filaments is which of the following?
a. Generate movement
b. Provide mechanical stability
c. Carry out nucleation of microtubules
d. Stabilize microtubules against disassembly
e. Transport organelles within the cell
(Micrograph Courtesy of Dr. Doniel Friend.)