Q: In the context of RNA interference (RNAi), which equation best represents the effect of miRNA binding to its target mRNA?

$$\text{miRNA} + \text{target mRNA} \rightarrow \text{degraded mRNA}$$

Question 1

Which of the following best describes the primary function of microRNAs (miRNAs) in eukaryotic cells?

Accepted Answer

They regulate gene expression by promoting mRNA degradation or inhibiting translation.

Question 2

siRNAs and miRNAs are both produced from double-stranded RNAs. Which process is most directly responsible for generating these double-stranded RNAs from DNA?

Accepted Answer

Transcription of inverted repeat sequences in DNA.

Question 3

In the context of RNA interference (RNAi), which equation best represents the effect of miRNA binding to its target mRNA?

Accepted Answer

$$	ext{miRNA} + 	ext{target mRNA} ightarrow 	ext{degraded mRNA}$$

Question 4

You are studying the gene FOXP2. If miRNAs complementary to FOXP2 mRNA are present, what would you expect to happen to FOXP2 mRNA and protein levels?

Accepted Answer

FOXP2 mRNA degradation increases; FOXP2 protein production decreases.

Question 5

Which of the following statements about intragenic miRNAs is correct?

Accepted Answer

They are encoded within the introns or exons of a protein-coding host gene.

Question 6

Where do miRNAs typically exert their regulatory effects?

Accepted Answer

In the cytoplasm of the cell producing the miRNA.

Question 7

Some plants secrete miRNAs that can be taken up by fungi. What is the most likely function of these secreted miRNAs?

Accepted Answer

To communicate with other organisms.

Question 8

Why might using dsRNA-based RNAi as a pesticide be preferable to traditional chemical pesticides?

Accepted Answer

It can target specific genes in pests, reducing off-target effects and environmental impact.

Question 9

Which of the following is a potential risk when applying dsRNA-based RNAi in agriculture?

Accepted Answer

Off-target effects on non-target organisms and endogenous genes.

Question 10

How do miRNAs recognize and bind to their target mRNAs?

Accepted Answer

Through complementary base pairing between the miRNA and the target mRNA sequence.

Question 11

Which of the following best describes the difference between XY and ZW sex determination systems?

Accepted Answer

In XY systems, males are heterogametic (XY) and females are homogametic (XX); in ZW systems, females are heterogametic (ZW) and males are homogametic (ZZ).

Question 12

Which mechanism do placental mammals use to compensate for differences in X chromosome gene dosage between sexes?

Accepted Answer

X-inactivation, where one X chromosome in females becomes transcriptionally inactive.

Question 13

What role does miRNA play in the process of X-inactivation in placental mammals?

Accepted Answer

miRNAs help regulate the silencing of genes on the inactivated X chromosome.

Question 14

Which of the following equations represents the complementary base pairing used by CRISPR for gene editing?

Accepted Answer

$$	ext{gRNA} + 	ext{target DNA} ightarrow 	ext{Cas9-mediated cleavage}$$

Question 15

Gene expression in eukaryotes can be regulated at multiple levels. Which of the following is NOT a level of gene expression control?

Accepted Answer

Lipid synthesis control

Question 16

A researcher uses RNAi to knock down a gene in Drosophila. Which result would best indicate the gene's function?

Accepted Answer

Observing changes in the organism's phenotype after gene knockdown.

Question 17

Which of the following is true about the relationship between host gene mRNA and target mRNA for miRNA regulation?

Accepted Answer

Host gene mRNA and target mRNA are usually the same.

Question 18

Which of the following scenarios best illustrates the use of RNAi in a laboratory setting to study gene function?

Accepted Answer

Introducing siRNA specific to a gene and observing the resulting phenotype.

Question 19

Which of the following is a correct statement about the production of miRNAs?

Accepted Answer

miRNAs are processed from double-stranded RNA hairpins transcribed from DNA.

RNA Interference (RNAi), microRNAs, and Genetic Sex Determination: Study Notes

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