Question 1

Which of the following best describes the principle behind the DNase I hypersensitivity assay used to detect open chromatin?

Accepted Answer

DNase I digests accessible chromatin, and the resulting fragments are purified and sequenced to identify open regions.

Question 2

A researcher uses ChIP-seq to study transcription factor binding in a cell type. What is the main advantage of ChIP-seq over DNase-seq in this context?

Accepted Answer

ChIP-seq reveals the specific DNA sequences bound by a particular transcription factor.

Question 3

Which of the following statements about pioneer transcription factors is CORRECT?

Accepted Answer

They can bind to their target DNA sequences even in closed chromatin and initiate chromatin opening.

Question 4

Which of the following is a general mechanism by which eukaryotic transcription factors can repress transcription?

Accepted Answer

Blocking or competing for binding sites with other transcription factors.

Question 5

The mediator complex in eukaryotic transcription regulation primarily functions to:

Accepted Answer

Serve as a molecular bridge between enhancers and the transcriptional machinery at promoters.

Question 6

Which of the following best explains why most transcription factors cannot bind DNA in heterochromatin?

Accepted Answer

The DNA is tightly packed and inaccessible to most transcription factors.

Question 7

A scientist wants to generate induced pluripotent stem cells (iPSCs) from differentiated fibroblasts. Which combination of transcription factors is commonly used for this process?

Accepted Answer

SOX2, KLF4, OCT4, c-MYC

Question 8

Which of the following is a function of the effector domain of a transcription factor?

Accepted Answer

Interacting with co-activators or co-repressors to modulate transcription.

Question 9

The GAL4/UAS system is widely used in Drosophila genetics because it allows researchers to:

Accepted Answer

Conditionally express genes in specific tissues or at specific times.

Question 10

Which of the following best describes the role of Polycomb group (PcG) complexes in development?

Accepted Answer

They help establish and maintain cell type-specific patterns of facultative heterochromatin, repressing genes not needed in a given cell type.

Question 11

A mutation in a gene encoding a mediator subunit results in reduced transcription of many genes. Which of the following best explains this observation?

Accepted Answer

Mediator is required for the recruitment of RNA polymerase II to promoters.

Question 12

Which of the following is a direct effect of thyroid hormone binding to its nuclear receptor?

Accepted Answer

The receptor dimerizes and binds to thyroid response elements (TREs) in DNA, regulating gene expression.

Question 13

Which of the following equations correctly represents the probability $$P of a $$transcription factor binding to a specific DNA sequence, given the concentration $$[TF]$$ and the dissociation constant $$K_d$$?

Accepted Answer

$$P = \frac{[TF]}{[TF] + K_d}$$

Question 14

Which of the following mechanisms is NOT a way that transcription factors can activate gene expression?

Accepted Answer

Blocking the binding of RNA polymerase to the promoter.

Question 15

In the context of induced pluripotent stem cells (iPSCs), which of the following best describes 'directed differentiation'?

Accepted Answer

Exposing iPSCs to signals and conditions that mimic normal embryonic development to generate specific differentiated cell types.

Question 16

Which of the following is a real-world application of iPSC technology as described in the lecture?

Accepted Answer

Generating patient-derived retinal pigment epithelial cells for age-related macular degeneration (AMD) treatment.

Question 17

Which of the following best describes the function of the Trithorax group (TrxG) proteins in chromatin regulation?

Accepted Answer

They add activating histone marks such as H3K4me3 to maintain gene expression.

Question 18

A mutation disrupts the DNA-binding domain of a transcription factor. Which of the following is the most likely consequence?

Accepted Answer

The transcription factor cannot bind to its target DNA sequences, reducing its regulatory activity.

Question 19

Which of the following best explains why thyroid hormone can regulate gene expression in multiple tissues during amphibian metamorphosis?

Accepted Answer

Thyroid hormone receptors are expressed in various tissues, and binding to TREs regulates tissue-specific gene expression.

Regulation of Eukaryotic Transcription: Mechanisms, Factors, and Applications

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