Following statements are regarding to V-class ATPases.

A. An organelle lumen or an extracellular space to become acidic, movement of protons must be accompanied by movement of an equal number of anions (e.g., Cl−) in the same direction.

B. An organelle lumen or an extracellular space to become acidic, movement of protons must be accompanied by movement of equal numbers of a different cation in the same direction.

C. An organelle lumen or an extracellular space to become acidic, movement of protons must be accompanied by movement of equal numbers of a different cation in the opposite direction.

D. An organelle lumen or an extracellular space to become acidic, movement of protons must be accompanied by movement of an equal number of anions (e.g., Cl−) in the opposite direction.

Which of the following combination is correct?

#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.

#Question id: 4090

#Unit 3. Fundamental Processes

Tryptophan synthesis can be controlled by a process called attenuation in which the levels of tryptophan in the cell control translation by