The final RNA processing event, polyadenylation of the 3’end of the mRNA, is intimately linked with the termination of transcription. Just as with capping and splicing, the polymerase CTD tail is involved in recruiting some of the enzymes necessary for polyadenylation,

#Question id: 2150

#Unit 2. Cellular Organization

Which of the following increase(s) membrane fluidity?

#Question id: 2151

#Unit 2. Cellular Organization

Which of the following statement(s) is (are) true of transmembrane proteins?

a. All contain a hydrophobic α helix.

b. Some serve as membrane attachment sites for peripheral membrane proteins.

c. Some contain more than one membrane-spanning domain.

d. All are asymmetrically oriented in the lipid bilayer.

#Question id: 2152

#Unit 2. Cellular Organization

Precursors of membrane phospholipids are

a. soluble in the cytosol.                    

b. incorporated into biosynthetic intermediates.

c. sometimes complexed with fatty-acid-binding proteins.

d. stored in glycerolosomes.

e. sometimes activated by conjugation with CDP.

#Question id: 2153

#Unit 2. Cellular Organization

Membrane phospholipids include

a. cholesterol.            

b. plasmologens.        

c. sphingolipids.         

d. triglycerides.                      

e. bile acids.

#Question id: 2154

#Unit 2. Cellular Organization

Membrane lipids are distributed appropriately between the two leaflets of a given membrane by

a. dockases.    

b. trumpases.              

c. fatty acid desaturases.        

d. flippases.    

e. transmembrane tunnelases.

#Question id: 2155

#Unit 2. Cellular Organization

Cholesterol is

a. unrelated to any plant lipids.                     

b. not found in chloroplast membranes.

c. encoded by an intron-containing gene on chromosome 23.

d. relatively abundant in the plasma membrane and endocytic membranes.

e. synthesized in the ER.