$$\text{Cys}-X_3$-\text{Cys}-X_{3-5}-\text{Phe}-X_{2-4}-\text{Leu}-X_2$-\text{His}-X_3$-\text{His}$$

Question 1

Which of the following best explains why the default state of transcription in eukaryotes is 'OFF'?

Accepted Answer

Eukaryotic DNA is associated with nucleosomes and supercoiled chromatin, making it inaccessible to the transcription machinery without activators.

Question 2

A mutation prevents the nuclear localization of a transcriptional activator in liver cells. What is the most likely consequence?

Accepted Answer

Target genes regulated by this activator will not be expressed in liver cells.

Question 3

Which of the following is a key difference between gene regulation in prokaryotes and eukaryotes?

Accepted Answer

Prokaryotes primarily use repressors to regulate gene expression, while eukaryotes rely more on activators.

Question 4

A gene is described as 'poised' in a eukaryotic cell. Which of the following best characterizes its state?

Accepted Answer

It is accessible and displays epigenetic markers for both activation and repression, but is not currently transcribed.

Question 5

Which protein domain is responsible for binding to promoters or enhancers and providing specificity in true activators?

Accepted Answer

DNA binding domain (DBD)

Question 6

Steroid hormone receptors are classified as which type of DNA binding domain motif?

Accepted Answer

Cys2/Cys2 zinc finger proteins

Question 7

Which of the following mechanisms is NOT a way that repressors regulate gene expression in eukaryotes?

Accepted Answer

Directly binding to the promoter to block RNA polymerase in the absence of activators

Question 8

A transcription factor contains a leucine zipper motif. What is the primary function of the leucine zipper region?

Accepted Answer

Dimerization of the transcription factor

Question 9

Which equation best represents the consensus sequence for a classical C2H2 zinc finger protein?

Accepted Answer

$$	ext{Cys}-X_3$-	ext{Cys}-X_{3-5}-	ext{Phe}-X_{2-4}-	ext{Leu}-X_2$-	ext{His}-X_3$-	ext{His}$$

Question 10

During embryonic development, the expression of certain genes changes over time. This is best explained by which concept?

Accepted Answer

Divergent temporal patterns due to changes in transcription regulatory sequences

Question 11

Which of the following is a function of architectural proteins in gene regulation?

Accepted Answer

Bind DNA to bring together or separate proteins in a cooperative complex

Question 12

A researcher discovers a transcription factor that binds DNA only after phosphorylation. Which regulatory mechanism is this an example of?

Accepted Answer

Regulation of activator activity by post-translational modification

Question 13

Which of the following statements about gene-specific transcription regulation is correct?

Accepted Answer

Core promoter is necessary but not sufficient for physiological levels of gene expression.

Question 14

Which of the following is NOT a property of true activators?

Accepted Answer

They always require coactivators to bind DNA.

Question 15

Which of the following best describes the role of co-activators in transcription regulation?

Accepted Answer

They do not bind DNA directly but mediate interaction between true activators and the basal transcription apparatus.

Question 16

Which of the following is a common feature of all zinc-finger transcription factors?

Accepted Answer

The C2H2 motif is important for structure but does not determine DNA binding specificity.

Question 17

Which of the following is a mechanism by which gene regulatory networks contribute to tissue and cell specification during development?

Accepted Answer

They coordinate the expression of sets of genes through interactions among multiple transcription factors.

Question 18

Which of the following statements about DNA binding domain (DBD) classes is correct?

Accepted Answer

Proteins of the same motif may have similar structures but do not necessarily recognize the same DNA sequences.

Eukaryotic Transcription Regulation: Mechanisms, Activators, and DNA Binding Domains

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