Question

2 After isolating the rough endoplasmic reticulum from the rest of the cytoplasm, you purify the RNAS attached to it. Which of the following proteins do you expect the RNA from the rough endoplasmic reticulum to encode? (a) (c) soluble secreted proteins plasma membrane proteins ER membrane proteins all of the above (b) (d) -13 In which cellular location would you expect to find ribosomes translating MRNAS that encode ribosomal proteins? (a) (c) the nucleus in the cytosol on the rough ER in the lumen of the ER (b) (d) 5-15 What is the role of the nuclear localization sequence in a nuclear protein? (a) It is bound by cytoplasmic proteins that direct the nuclear protein to the nuclear pore. It is a hydrophobic sequence that enables the protein to enter the nuclear membranes. (b) It aids in protein unfolding so that the protein can thread through nuclear pores. (c) It prevents the protein from diffusing out of the nucleus through nuclear pores. (d) 15-17 Your friend works in a biotechnology company and has discovered a drug that blocks the ability of Ran to exchange GDP for GTP. What is the most likely effect of this drug on nuclear transport? (a) (b) (c) (d) Nuclear transport receptors would be unable to bind cargo. Nuclear transport receptors would be unable to enter the nucleus. Nuclear transport receptors would be unable to release their cargo in the nucleus. Nuclear transport receptors would interact irreversibly with the nuclear pore fibrils. 15-18 You are interested in Fuzzy, a soluble protein that functions within the ER lumen. Given that information, which of the following statement must be true? Fuzzy has a C-terminal signal sequence that binds to SRP. (a) Only one ribosome can be bound to the mRNA encoding Fuzzy during translation. Fuzzy must contain a hydrophobic stop-transfer sequence. Once the signal sequence from Fuzzy has been cleaved, the signal peptide will be ejected into the ER membrane and degraded. (b) (c) (d) 5-19 Figure Q15-19 shows the organization of a protein that normally resides in the plasma membrane. The boxes labeled 1 and 2 represent membrane-spanning sequences and the arrow represents a site of action of signal peptidase. Given this diagram, which of the following statements must be true? Figure Q15-19 The N-terminus of this protein is cytoplasmic. The C-terminus of this protein is cytoplasmic. The mature version of this protein will span the membrane twice, with both the N and C-termin in the cytoplasm. None of the above. (b) (c) (d)

Please answer all questions

Answer 1

Hi there, as the number of questions asked are huge so I would very briefly answer all your questions,

15-12= The correct option is D. After the mRNA is translated into proteins, the polypeptide chain is transported to RER membrane, it is from RER that all kinds of protein whether membrane proteins or soluble proteins etc are transported to their respective places.

15-13= The correct option is C. Ribosomes are found free in the cytosol, where they bind to mRNA and help in translation of mRNA into proteins.

15-14= The correct option is A. It utilises proteins like karyopherins and ran-GTP to aid the movement of proteins translated with the help of nuclear localisation sequence to nuclear core.

15-16= The correct option is C. It is ran that exchanges GDP for GTP and induces a affinity change in importin and protein complex that the protein is able to release into nucleus from nuclear pore.

15-17= The correct option is D.

15-18= The correct option is B.

Hope this helps.