Ubiquitin-mediated protein degradation is a complex process, and many of the signals remain unknown.  One known signal involves recognition of amino acids in a processed protein that are either stabilizing (Ala, Gly, Met, Ser, etc.) or destabilizing (Arg, Asp, Leu, Lys, Phe, etc.), and are located at:

#Question id: 4276

#Unit 3. Fundamental Processes

Which of the following post-translational modifications of proteins occur(s) in the lumen of the endoplasmic reticulum?

a. glycosylation                       b. formation of disulfide bonds

c. conformational folding and formation of quaternary structure

d. proteolytic cleavage                        e. aldol condensation of sugars

#Question id: 4277

#Unit 3. Fundamental Processes

N-linked oligosaccharides in glycoproteins

#Question id: 4278

#Unit 3. Fundamental Processes

N-terminal sequences usually function as targeting signals for protein transport into

a. the nucleus.             b. peroxisomes.                       c. chloroplasts.

d. the rough endoplasmic reticulum.   e. mitochondria.

#Question id: 4279

#Unit 3. Fundamental Processes

The energy required for protein transport into mitochondria is provided by

#Question id: 4280

#Unit 3. Fundamental Processes

Translocation of proteins into mitochondria and chloroplasts is characterized by

#Question id: 4281

#Unit 3. Fundamental Processes

Proteins targeted to non-matrix regions of mitochondria

a. contain a matrix-targeting signal if the destination is the outer membrane.

b. utilize a stop-transfer signal if the destination is the outer membrane.

c. always contain a matrix-targeting signal if the destination is the intermembrane space.

d. may require a chaperone for transport.

e. always move first to the matrix and then to their final destination.