Question

25. What is a riboswitch?

A. a small molecule that regulates the translation of specific mRNAs

B. a gene regulatory protein that turns on the expression of ribosomal proteins

C. an mRNA that can regulate its own transcription and translation

D. a ribosome that participates in attenuation

E. when the antisense RNA binds to the transcript

26. In the Ames Test, the appearance of his+ revertants in the

presence of a non-mutagenic

control compound indicates that _______.

A. liver extract increases the potency of some mutagens

B. the growth medium must contain liver extract

C. the non-mutagenic control was contaminated by Kanye West

D. some of the reversion mutations are not caused by the mutagen being tested

27. Which of the following is ONLY TRUE of retrotransposon

s and not simple or replicative

transposons?

A. they require repeats to move

B. if they jump into a functional gene, it will be mutated

C. they require some sort of enzyme for the movement

D. they require an RNA intermediate

E. they require a cell-mediated transfer

Answer 1

1.(25) As evident from its name “Riboswitch”, is a part of messenger RNA of bacteria generally present at 5’-untranslated region which controls the expression of its own downstream region.

It has two main domains one is called as aptamar domain which acquire three dimensional pocket to accommodate the regulatory metabolite or ligand and other is called as expression plateform that has secondary structural switch which interferes  with the transcription and translation of the downstream coding region of same mRNA.

Therefore, the option ’C’ is the correct option.

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