Question 1

Discuss the features of C. elegans that make it an important model system for studies of animal genetics and development. Include in your answer some unique features of C. elegans compared to other model systems.

Accepted Answer

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Question 2

Below is a list of steps in the processing of ribosomal RNAs. Please select the choice that lists the steps in the CORRECT sequential order. 1. Methyl groups added to specific bases and the 2'-carbon atom of some ribose sugars
2) Transcription of the rRNA precursors from DNA
3) Cleavage of precursor rRNA
4) Individual rRNA molecules ready for ribosome assembly
5) Trimming of precursor rRNA

Accepted Answer

The correct order is: Transcription of the rRNA precursors from DNA, Methyl groups added, Cleavage of precursor rRNA, Trimming of precursor rRNA, and Individual rRNA molecules ready for ribosome assembly.

Question 3

siRNAs and miRNAs function in which of the following processes?

Accepted Answer

siRNAs and miRNAs are involved in RNA interference, a process that regulates gene expression by degrading or blocking the translation of specific mRNA molecules.

Question 4

A scientist is studying a gene known as the XYZ gene in eukaryotes. Into a eukaryotic cell, she inserts an miRNA that is complementary to a portion of the XYZ mRNA found in the cell. What result would you predict?

Accepted Answer

The miRNA will bind to the complementary mRNA, leading to its degradation or preventing its translation, resulting in a decrease in the amount of XYZ protein made.

Question 5

Compare and contrast the mechanisms of splicing for nuclear pre-mRNA introns, group I introns, group II introns, and tRNA introns.

Accepted Answer

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Question 6

Which of the following regulatory RNA types is different from the rest in terms of its length?

Accepted Answer

lncRNA is the only regulatory RNA type that is longer than 200 nucleotides, while the others are typically less than 30 nucleotides in length.

Question 7

Which class of RNA is MOST abundant in cells?

Accepted Answer

Ribosomal RNA (rRNA) is the most abundant type of RNA in cells, as it makes up the major component of ribosomes, which are essential for protein synthesis.

Question 8

Which of the following small RNA types is unique to prokaryotes?

Accepted Answer

crRNA (CRISPR RNA) is unique to prokaryotes as it is part of the CRISPR-Cas system used by bacteria and archaea for adaptive immunity against viruses.

Question 9

What is the similarity between miRNAs, siRNAs, and piRNAs?

Accepted Answer

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Question 10

A drug that destroyed small nucleolar RNA (snoRNA) would inhibit which process?

Accepted Answer

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Question 11

Which of the following classes of RNAs is unique to eukaryotes?

Accepted Answer

Small nuclear RNAs (snRNAs) are unique to eukaryotes and are involved in the splicing of pre-mRNA.

Question 12

Which of the following rRNA components originates from a separate gene transcript rather than as a cleaved product of a long single precursor rRNA transcript?

Accepted Answer

Eukaryotic 5S rRNA is transcribed from a separate gene by RNA polymerase III, unlike other rRNAs which are transcribed as part of a precursor by RNA polymerase I.

Question 13

A scientist is studying a gene known as the ABC gene in bacteria. Into a bacterial cell, she inserts an miRNA that is complementary to a portion of the ABC mRNA found in the cell. What result would you predict?

Accepted Answer

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Question 14

What attributes make miRNA a potent agent for silencing gene expression by allowing it to silence a large number of genes simultaneously?

Accepted Answer

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Question 15

A microbiologist isolated a mutant strain of E. coli that is extremely susceptible to bacteriophage infection, by a wide range of bacteriophages. Which of the following genes might she explore as a possible site of the mutation that results in this phenotype?

Accepted Answer

The Cas protein is part of the CRISPR-Cas system, which provides bacteria with adaptive immunity against bacteriophages. A mutation in a gene encoding a Cas protein could impair this defense mechanism, making the bacteria more susceptible to phage infection.

Quiz 14: Rna Molecules and Rna Processing