TLS Online TPP Program

#Question id: 4995


It has been found that certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This is evidence in support of the claim that

#Unit 9. Evolution & Diversity of Life Forms
  1. some structures are so complex that natural selection cannot, and will not, explain their origins.

  2. the power of natural selection allows it to act in an almost predictive fashion, producing organs that will be needed in future environments.

  3. the motors of bacterial flagella were originally synthesized abiotically.

  4. natural selection can produce new structures by cobbling together parts of other structures.

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TLS Online TPP Program

#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.

TLS Online TPP Program

#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.

TLS Online TPP Program

#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.

TLS Online TPP Program

#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.

TLS Online TPP Program

#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

TLS Online TPP Program

#Question id: 4091

#Unit 3. Fundamental Processes

To avoid being degraded by nuclear exonucleases, nascent transcripts, pre-mRNA-processing intermediates, and mature mRNAs in the nucleus must have their ends protected. Which of the following mechanism are present in the cell to protect mRNA from degradation?

I. The 5′ cap is protected because it is bound by a heterodimeric nuclear cap-binding complex (CBC), which protects it from 5′ exonucleases and also functions in export of the mRNA to the cytoplasm.

II. 5’-5’ phosphodiester bond in the cap of mRNA plays crucial role in protection

III. The 3′ end of a nascent transcript lies within the RNA polymerase and is thus inaccessible to exonucleases