Histology NBME Exam Questions with Correct Answers

Dynein Correct Answer A class of motor proteins that convert cellular energy to mechanical energy. They allow for migration, propagation, and movement of cells/organelles usually along the microtubules. microtubules Correct Answer A cytoskeletal element found in cilia, flagella, the mitotic spindle, and centrioles. Involved in cell division, cell movement, and axonal trafficking in neurons. Consists of a cylindrical outer structure of helical, polymerized heterodimers of α- and β-tubulin. Grows slowly but collapses quickly. Motor proteins (e.g., dynein and kinesin) move cellular products on microtubule scaffolds. membrane proteins Correct Answer A collection of proteins that are embedded in the lipid bilayer of membranes. Includes integral membrane proteins, which are embedded within the lipid bilayer, and peripheral membrane proteins, which are attached to the outer lipid bilayer. cells rich in rER Correct Answer Cells rich in rER include cells of the exocrine pancreas, antibody-secreting plasma cells, and mucus-secreting goblet cells. cells rich in sER Correct Answer Cells rich in sER include hepatocytes and cells of the adrenal cortex and the gonads which are hormone producing cells Vesicular trafficking proteins Correct Answer clathrin for Golgi → lysosomes & receptor-mediated endocytosis, COP I for Golgi → ER (retrograde, 1 step backward ), COP II for ER → Golgi (anterograde, 2 step forward)