The primitive streak is derived from epiblast cells and the central cells of Koller’s sickle. As the primitive streak extends rostrally, Henson’s node is formed. Following are few statements regarding this:

A. As endodermal ingression continues, the primitive streak starts to regress, moving Henson’s node from near the center of the area pellucida to a more posterior position.

B. As endodermal ingression continues, the primitive streak starts to regress, moving Henson’s node from near the periphery of the area pellucida to a more posterior position.

C. As mesodermal ingression continues, the primitive streak starts to regress, moving Henson’s node from near the center of the area pellucida to a more posterior position.

D. As mesodermal ingression continues, the primitive streak starts to regress, moving Henson’s node from near the periphery of the area pellucida to a more anterior position.

Which of the following statements are correct?

#Question id: 4083

#Unit 3. Fundamental Processes

Differential splicing of the Ca2+-activated K+ channel gene in ciliated neurons results in

a. hair cells with different response frequencies.

b. different channel isoforms.

c. channels that open at different calcium concentrations.

d. different channel mRNAs expressed in different cells.

#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.