Question

19. Movement of molecules from one side of an epithelial layer to the other is prevented from going in between cells by

A. Adherens junctions

B. Tight junctions

C. Gap junctions

D. Desmosomes

E. Hemidesmosomes

20. How are olfactory receptor cells depolarized upon binding to odorants?

A. The odorant binds to a ligand gated ion channel .

B. The odorant binds to a receptor tyrosine kinase

C. The odorant binds to a G protein coupled receptor

D. The odorant binds to a cAMP gated ion channel

E. The odorant binds to gap junctions

21. Autophagy is

A. A trafficking pathway to the lysosome

B. The engulfment of defective organelles or protein aggregates by a double membrane vesicle

C. Activated by starving the cells

D. Was discovered in yeast

E. All of the above

22. You have discovered a mutant cell line that has defective endosomes that you suspect are 10% larger in size. The best way to determine if this is true would be to perform

A. Scanning electron microscopy

B. Transmission electron microscopy

C. Laser scanning confocal microscopy

D. X-ray crystallography

E. NMR spectroscopy

23. A scaffold protein would mostly contain _________ domains

A. Kinase

B. Phosphatase

C. Immunoglobulin

D. Protein-protein binding domains

E. All of the above

Answer 1

19. Option B is correct
Tight junctions = Occluding junctions
Movement of molecules from one side of an epithelial layer to the other is prevented by Tight junctions.
Tight junctions bind cells together, help to maintain polarity, and prevent the movement of molecules.

20. Option C is correct
During olfactory signaling, the ligand binds to the GPCR (G-protein coupled receptor)

21. Option D is correct
Autophagy is a natural mechanism that involves the removal of dysfunctional and unnecessary cellular components.
It involves targeting of defective components to the lysosome.