706_S2006_Exam3key - Name: _KEY_ 7.06 Cell Biology EXAM #3...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Name: ____________KEY__________________ 1 7.06 Cell Biology EXAM #3 KEY May 2, 2006 This is an OPEN BOOK exam, and you are allowed access to books, a calculator, and notes BUT NOT computers or any other types of electronic devices. Please write your answers in PEN (not pencil) to the questions in the space allotted. Please write only on the FRONT SIDE of each sheet, as we will Xerox all of the exams and thus only grade writing on the front. And be sure to put your NAME ON EACH PAGE in case they become separated! There are SEVEN pages including this cover sheet. Question 1. 24 pts __________ Question 2. 15 pts __________ Question 3. 27 pts __________ Question 4. 19 pts __________ Question 5. 15 pts __________ TOTAL 100 pts __________
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Name: ____________KEY__________________ 2 Question 1. (24 pts.) For each of the following engineered proteins, predict which location in the cell they would be targeted to. Assume that each targeting sequence is at the site along the protein (N terminus, C terminus, internal) where it would normally be found. Also assume that the only targeting sequences possessed by each protein are those listed. Choose from the choices : the cytoplasm, the nucleus, the nuclear membrane, the peroxisome, the peroxisomal membrane, the outer mitochondrial membrane, the intermembrane space of the mitochondria, the inner mitochondrial membrane, the mitochondrial matrix, the lumen of the ER, or the membrane of the ER. (a, 4 pts) an NES and a mitochondrial matrix targeting sequence The mitochondrial matrix. The NES would have no effect on the protein’s localization, because a protein cannot be targeted for export from the nucleus if it is never targeted to the nucleus in the first place. Thus an NES is meaningless without an NLS. (b, 4 pts) a cleavable signal sequence and a stop transfer sequence The membrane of the ER. The signal sequence at the N terminus would be recognized by SRP. SRP would bind the sequence, halt translation, and target the protein to the ER. Part of the way through translation, the ribosome would synthesize the stop transfer sequence. This sequence would diffuse out of the translocon and imbed in the ER membrane. The C terminus of the protein would then be made and remain in the cytosol. (c, 4 pts) a mitochondrial matrix targeting sequence and a stop transfer sequence The inner mitochondrial membrane. The mitochondrial matrix targeting sequence at the N terminus would be recognized by the import receptor, which would target the protein to the matrix. Part of the way through translocation, the stop transfer sequence would start to go through the translocon. This sequence would diffuse out of the translocon and imbed in the inner mitochondrial membrane. The rest of the protein would remain in the intermembrane space. This could not be an outer mitochondrial membrane protein, because those proteins require a special outer membrane localization sequence such that the protein does not go all the way
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/23/2012 for the course BIOLOGY lsm1301 taught by Professor Seow during the Spring '11 term at National University of Singapore.

Page1 / 9

706_S2006_Exam3key - Name: _KEY_ 7.06 Cell Biology EXAM #3...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online