Question #1 Which of the following statements about nuclear pores is False ? 1.)
ID: 97616 • Letter: Q
Question
Question #1 Which of the following statements about nuclear pores is False? 1.) They are comprised of more than 30 different proteins. 2.) The cytoplasmic and nuclear sides of the pores are distinct. 3.) All protein trafficking through nuclear pores is receptor mediated. 4.) All protein trafficking through nuclear pores is unidirectional. 5.) Transport through the nuclear pores is energy dependent. (***Only one of these is false) Question #2 How would you design an experiment to demonstrate that the NLS (nuclear localization signal) of the yeast protein Swi5 is sufficient for the transport of this protein into the nucleus? 1.) Alter the sequence of Swi5 so that the NLS is deleted and demonstrate that the altered Swi5 protein cannot be detected in the nucleus. 2.) Create a fusion between the NLS of Swi5 and a gene that is not normally found in the nucleus and demonstrate that this new fusion protein is now detected in the nucleus. 3.) Compare the sequences of all of the known nuclear proteins in yeast and identify the amino acid sequence that is common to all of them. 4.) Demonstrate that the NLS can bind importin . 5.) Either experiment A or B would demonstrate that the NLS of Swi5 is sufficient for nuclear transport. Question #3 Transport of a protein (cargo) from the cytoplasm into the nucleus occurs through the translocation of a complex of proteins including the cargo bound to importin proteins ( and ). What mechanism ensures that this complex does not exit the nuclear pore complex (NPC) once it has passed through the nuclear pore and into the nucleus? 1.) No specific mechanism is required because transport of proteins is always unidirectional through the NPC. 2.) The shape of the NPC is such that the basket region on the inner surface of the nuclear membrane allows passage of this protein complex in one direction into the nucleus but not out. 3.) Export from the nucleus requires distinct NPCs and distinct proteins called exportins. 4.) Ran-GTP is enriched in the nucleus and binds the complex, causing the disassociation of cargo and importins and trapping the cargo in the nucleus. 5.) Ran-GTP is enriched in the nucleus and hydrolyzes GTP to GDP to phosphorylate the importins, causing the disassociation of cargo and importins and trapping the cargo in the nucleus. Question #4 Which statement is true about the UPR? 1.) Hac1 is continually transcribed but only translated in response to the UPR 2.) Hac1 is continually transcribed but only translated in response to the UPR 2.) Hac1 is transcribed and translated in response to the dimerization of Ire1 3.) Increasing chaperone proteins is the only thing a UPR signal does for the cell 4.) Ire1 dimerizes in the ER and then translocates to the nucleus to signal the UPR
Explanation / Answer
Question # correct answer 1 4.) All protein trafficking through nuclear pores is unidirectional. (False statement). 2 5.) Either experiment A or B would demonstrate that the NLS of Swi5 is sufficient for nuclear transport. 3 4.) Ran-GTP is enriched in the nucleus and binds the complex, causing the disassociation of cargo and importins and trapping the cargo in the nucleus 4 2.) Hac1 is transcribed and translated in response to the dimerization of Ire1