6. True or false
a_______ Nuclear pore complexes are specialized so that some mediate import and others mediate export
b_______ Membrane-bound and free ribosomes, which are structurally and functionally identical, differ only in the proteins they happen to be making at a particular time.
c_______ Some proteins can be made as either free or membrane-bound proteins. They have the same mRNA but different splicing and poly-adenylation patterns
d_______ a protein that does not have a sorting signal will be tagged for destruction by ubiquitin
e_______ when the hydrophobic signal peptide emerges from the ribosome, it is bound by SRP, which causes a pause in protein synthesis. Synthesis resumes when the ribosome with a bound SRP then binds to the SRP receptor on the cytosolic surface of the rough ER.
f________ A protein cannot leave the ER unless it is correctly folded
g________ All of the glycoproteins and glycolipids in intracellular membranes have their oligosaccharide chains facing the cytosolic side, and all those in the plasma membrane have their oligosaccharide chains facing the outside of the cell.
6. True or false
a_______ Nuclear pore complexes are specialized so that some mediate import and others mediate export
b_______ Membrane-bound and free ribosomes, which are structurally and functionally identical, differ only in the proteins they happen to be making at a particular time.
c_______ Some proteins can be made as either free or membrane-bound proteins. They have the same mRNA but different splicing and poly-adenylation patterns
d_______ a protein that does not have a sorting signal will be tagged for destruction by ubiquitin
e_______ when the hydrophobic signal peptide emerges from the ribosome, it is bound by SRP, which causes a pause in protein synthesis. Synthesis resumes when the ribosome with a bound SRP then binds to the SRP receptor on the cytosolic surface of the rough ER.
f________ A protein cannot leave the ER unless it is correctly folded
g________ All of the glycoproteins and glycolipids in intracellular membranes have their oligosaccharide chains facing the cytosolic side, and all those in the plasma membrane have their oligosaccharide chains facing the outside of the cell.
