Question 1

Which of the following best describes the primary function of microRNAs (miRNAs) in gene regulation?

Accepted Answer

They negatively regulate gene expression by binding to target mRNAs and inducing degradation or inhibiting translation.

Question 2

A researcher is studying a non-coding RNA that is longer than 200 nucleotides, poorly conserved in sequence, and regulates gene expression at both transcriptional and posttranscriptional levels. Which class of ncRNA is most likely being investigated?

Accepted Answer

Long non-coding RNA (lncRNA)

Question 3

Which mechanism is responsible for the formation of circular RNAs (circRNAs) from exons, and what is a key structural feature that distinguishes circRNAs from linear RNAs?

Accepted Answer

Backsplicing; covalently closed continuous loop lacking 5' and 3' ends

Question 4

In the context of cardiac fibrosis, which microRNA is upregulated and promotes fibroblast activation via the ERK-MAP kinase pathway, and what is the effect of its pharmacological inhibition?

Accepted Answer

miR-21; inhibition reduces fibrosis and hypertrophy

Question 5

A scientist uses a luciferase assay to validate a predicted miRNA target. Which outcome would indicate that the miRNA binds to the 3' UTR of the target mRNA?

Accepted Answer

Decreased luciferase activity in the presence of the miRNA

Question 6

Which equation best represents the relationship between the number of non-coding RNAs (ncRNAs) and organismal complexity, as discussed in the study materials?

Accepted Answer

The number of ncRNAs is directly proportional to organismal complexity: $$N_{ncRNA} \propto C$$

Question 7

Which of the following best explains why lncRNAs can have conserved function despite poor sequence conservation?

Accepted Answer

Their three-dimensional structure, rather than primary sequence, determines molecular function.

Question 8

A patient with preeclampsia is found to have downregulated levels of the lncRNA Meg3 in placental samples. Based on the study materials, what is the most likely cellular effect of Meg3 downregulation?

Accepted Answer

Increased apoptosis and reduced migration of trophoblast cells

Question 9

Which of the following is a real-world example of a lncRNA acting as a molecular scaffold for chromatin-modifying complexes, and what is its effect?

Accepted Answer

HOTAIR; recruits PRC2 and LSD1 to repress HOXD locus gene expression

Question 10

Which equation describes the biogenesis of mature miRNA from its precursor, including the action of Drosha and Dicer?

Accepted Answer

pri-miRNA $$\xrightarrow{Drosha}$$ pre-miRNA $$\xrightarrow{Dicer}$$ mature miRNA

Question 11

Which of the following best describes the function of the lncRNA TINCR in human epidermal differentiation?

Accepted Answer

TINCR stabilizes differentiation-associated mRNAs by forming a complex with STAU1.

Question 12

A mouse model with Dicer deletion dies at embryonic day 7.5. What does this suggest about the role of miRNAs in development?

Accepted Answer

miRNAs are essential for the survival and differentiation of multipotent stem cells.

Question 13

Which of the following is a therapeutic approach for upregulating beneficial miRNAs in vivo, and what is a key consideration for tissue specificity?

Accepted Answer

Injection of miRNA mimics; use of cell-type specific promoters in adeno-associated viruses (AAV)

Question 14

Which equation represents the effect of miR-29 downregulation on extracellular matrix (ECM) gene expression in cardiac fibrosis?

Accepted Answer

ECM_{expression} \uparrow 	ext{ as } miR-29 \downarrow

Question 15

Which of the following best describes the function of circular RNA CDR1as (CiRS-7) in the brain?

Accepted Answer

CDR1as acts as a molecular sponge for miR-7, suppressing its activity.

Question 16

Which of the following is a real-world example of a lncRNA-based therapy currently in preclinical development, and what is its mechanism?

Accepted Answer

ASO targeting Ube3a-ATS to restore paternal Ube3a expression in Angelman syndrome

Question 17

Which of the following best explains why circulating ncRNAs are promising biomarkers for disease diagnosis?

Accepted Answer

They are stable due to association with vesicles and protein complexes, and their expression patterns correlate with disease states.

Non-coding RNAs: Biogenesis, Functions, and Roles in Development and Disease

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