Eating a meal leads to a large increase in gastric acid secretion that peaks within about 5 min and returns to normal about 4 hr after a meal is taken. How long after a meal does the pH of the gastric contents reach its lowest level (in hours)?

#Question id: 4084

#Unit 3. Fundamental Processes

The nuclear pore complex

a. is a large complex made of many different proteins.

b. is an octagonal, membrane-embedded structure with long filaments.

c. is required for transport of all molecules in or out of the nucleus.

d. binds to importin via FG-repeats.

e. hydrolyzes bound GTP to GDP

#Question id: 4085

#Unit 3. Fundamental Processes

When TAT protein fails to bind to the TAR region of the HIV transcript, which of the following statements is (are) true?

#Question id: 4086

#Unit 3. Fundamental Processes

RNA interference

a. utilizes antisense RNA.  

b. utilizes double-stranded RNA.

c. is used to silence expression of genes. 

d. utilizes short interfering RNAs.

#Question id: 4087

#Unit 3. Fundamental Processes

Polyadenylation can promote translation

a. of the fragile-X gene. 

b. of stored oocyte mRNAs.

c. by allowing for greater interaction at the 5´ end.

d. by allowing for greater interaction with translation initiation factors.

#Question id: 4088

#Unit 3. Fundamental Processes

The 28S, 18S, and 5.8S rRNAs are

a. transcribed by RNA polymerase II.

b. encoded by a single transcription unit.

c. arranged in tandem arrays. 

d. processed in the cytoplasm.

#Question id: 4089

#Unit 3. Fundamental Processes

An investigator incubates an unprocessed RNA molecule containing an intron in an extract absent of any protein. Correct splicing of the RNA is observed, but only when guanosine is present. What can the investigator conclude about the RNA molecule?

a. It contains a ribozyme. 

b. Self-splicing has occurred.

c. It contains a group II intron.

d. It contains a group I intron.