Q: Which equation best represents the central dogma of molecular biology?

$$DNA \rightarrow RNA \rightarrow \text{Protein}$$

Question 1

Which of the following best explains how a single genome can give rise to multiple cell types with different structures and functions in a multicellular organism?

Accepted Answer

Differential gene expression allows different sets of genes to be expressed in different cell types.

Question 2

A heart cell and a skin cell from the same individual have identical DNA. However, they produce different proteins. What is the primary reason for this difference?

Accepted Answer

Different genes are expressed in each cell type due to regulation of gene expression.

Question 3

Which step in gene expression is most commonly regulated in eukaryotic cells?

Accepted Answer

Transcription

Question 4

Transcription factors play a critical role in gene regulation. What is their main function?

Accepted Answer

They bind to promoter regions to regulate the initiation of transcription.

Question 5

Which of the following scenarios best illustrates post-transcriptional regulation?

Accepted Answer

MicroRNAs bind to mRNA, causing it to be degraded before translation.

Question 6

MicroRNAs are important regulators of gene expression. Which statement about their function is correct?

Accepted Answer

MicroRNAs bind to specific mRNAs, leading to their degradation or preventing their translation.

Question 7

A cell needs to rapidly produce a protein in response to a stimulus. Which regulatory mechanism allows for quick translation of stored mRNA?

Accepted Answer

Stockpiling mRNA with microRNA and protein tags, which are removed when the protein is needed.

Question 8

Which equation best represents the central dogma of molecular biology?

Accepted Answer

$$DNA ightarrow RNA ightarrow 	ext{Protein}$$

Question 9

If a mutation occurs in the promoter region of a gene, which process is most likely to be affected?

Accepted Answer

Transcription initiation

Question 10

Which of the following is a direct result of up-regulation of gene expression?

Accepted Answer

More protein is produced.

Question 11

A scientist discovers a new protein that binds to mRNA and prevents its degradation, but also blocks its translation. What is the most likely function of this protein?

Accepted Answer

It allows the cell to stockpile mRNA for rapid future translation.

Question 12

Which of the following best describes the role of repressors in gene regulation?

Accepted Answer

Repressors bind to DNA and decrease transcription.

Question 13

In a scenario where a cell is exposed to a toxin that causes rapid degradation of double-stranded RNA, which regulatory mechanism is most likely to be affected?

Accepted Answer

Post-transcriptional regulation by microRNAs.

Question 14

Which of the following is NOT a pathway through which cells regulate gene expression?

Accepted Answer

Regulation of DNA sequence by removing genes from the genome

Question 15

A mutation causes a cell to produce a nonfunctional transcription factor. What is the most likely consequence?

Accepted Answer

Specific genes will fail to be transcribed, affecting cell specialization.

Question 16

Which of the following best describes the relationship between genome and phenotype?

Accepted Answer

Phenotype results from differential gene expression of the genome.

Question 17

Which process is most likely to be affected if a cell loses the ability to degrade double-stranded RNA?

Accepted Answer

Post-transcriptional gene silencing by microRNAs

Question 18

A researcher observes that a certain mRNA is present in high amounts in a cell, but the corresponding protein is not detected. Which regulatory mechanism could explain this observation?

Accepted Answer

Post-transcriptional inhibition of translation by microRNAs

Question 19

Which of the following equations represents the process of transcription?

Accepted Answer

$$DNA \rightarrow RNA$$

Question 20

Which of the following is a real-world example of gene regulation in response to external stimuli?

Accepted Answer

A skin cell increases production of melanin after exposure to UV light due to up-regulation of melanin-producing genes.

Regulation of Gene Expression and Cell Specialization in Eukaryotes

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