Which of the following statements concerning ribosomal is NOT true? Precursor ri

Question

Which of the following statements concerning ribosomal is NOT true? Precursor ribosomal RNA is processed only in eukaryotic cells but not in bacterial cells. In eukaryotic, small nuclear RNAs help to process and assemble into mature ribosomal. A functional ribosome consists of large and small ribosomal subunits in both eukaryotes and prokaryotes. The genes for rRNA are present in multiple copies and moderately repeated throughout the genome. Each ribosomal subunit consists of one or more piece of RNA and a number of proteins. Which of the following statements INCORRECTLY describe rRNA processing? Ribsomal RNA is processed in both bacterial and eukaryotic cells. In eukaryotes, snRNAS function to cleave and modify the precursor rRNAs and then help assemble them into mature ribosomes. The bacterial rRNA precursor is methylated and then cleaved and trimmed to produce the 23S, 5S and 16S rRNA components. The eukaryotic 18S, 5.8S and 28S rRNA are generated from a single precursor rRNA transcript while 5S rRNA is encoded by a separate gene. In bacteria, a single gene that encodes all three RNA components. siRNAs and miRNAs are similar in all of the following EXCEPT that they mediate gene silencing through interacting with the RISC complex. Are both able to affect the gene expression and inhibit translation. Both originate from viral genes integrated during viral infection. Both from double stranded RNA during processing. Both get cleaved by an endoribonuclease named Dicer.

Explanation / Answer

13. A. Precursor ribosomal RNA is processed only in eukaryotic cells but not in bacterial cells.

14. B Option is incorrect.

Explanation:

snRNAs (small nuclear RNAs) range in size from 80 to 350 nucleotides.  They exist in all eukaryotes and small nuclearribonucleoproteins (snrps; made with snRNAs U1 through U6) which form a structure known as the spliceosome which control the splicing of pre-mRNAs to produce mRNAs.

15. D. A. Mediate gene slicing through interacting with the RISC complex.

Explanation:

siRNA is a synthetic molecule, consisting of double-stranded RNA with short single-stranded ends, which is transfected into cells and binds to RISC. siRNA is perfectly complementary to a particular target mRNA and cleaves that target.

miRNA is a natural molecule, also consisting of double-stranded RNA with short single-stranded ends. The double strand loads onto a complex which includes the Argonaute protein and Argonaute cleaves one strand of the dsRNA, incorporating the uncleaved single strand into the mature complex.

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