Which of the following events occur when E. coli is starved for tryptophan?

I.  The ribosome translates leader peptide completely

II. Transcription reads through attenuator into trp EDCBA

III. Tryptophanyl tRNA is not formed

IV. A stem loop structure involving regions 3 and 4 is formed at attenuator site

#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.

#Question id: 2156

#Unit 2. Cellular Organization

Proteins known to be involved in Golgi apparatus independent transport of lipids include

a. StAR protein.                                 

b. Neimann-Pick C1 (NPC1) protein.

c. HMG CoA reductase.                    

d. acyl:cholesterol acyl transferase (ACAT).

e. cholesterol 7α-hydroxylase.  

#Question id: 2157

#Unit 2. Cellular Organization

Which of the following is not a metabolic derivative of cholesterol?

a. dolichol                  

b. vitamin D               

c. bile acids    

d. v-SNARE molecules                     

e. NSF

#Question id: 2158

#Unit 2. Cellular Organization

Which of the following factors increase(s) the rate of simple (passive) diffusion of a solute across a phospholipid bilayer?

#Question id: 2159

#Unit 2. Cellular Organization

A channel protein