Question 1

Which of the following best describes the role of chromatin in eukaryotic gene regulation?

Accepted Answer

Chromatin generally acts as a repressor of transcription initiation, making the default state of many eukaryotic genes 'off'.

Question 2

In eukaryotes, which of the following is NOT a function of transcription activator proteins?

Accepted Answer

They directly synthesize mRNA from DNA.

Question 3

Which of the following statements about enhancers in eukaryotic gene regulation is TRUE?

Accepted Answer

Enhancers can function at flexible distances and orientations relative to the gene they regulate.

Question 4

A mutation in the TATA-binding protein (TBP) would most directly affect which process in eukaryotic cells?

Accepted Answer

Formation of the preinitiation complex at the promoter.

Question 5

Which of the following best explains why only 1-2% of the human genome codes for proteins?

Accepted Answer

Most of the genome consists of introns, regulatory sequences, and repetitive DNA.

Question 6

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

Accepted Answer

Eukaryotic genes involved in the same process are not physically linked, unlike prokaryotic operons.

Question 7

A researcher finds a eukaryotic gene that is only expressed in liver cells. Which of the following best explains this observation?

Accepted Answer

The gene has liver-specific enhancer sequences that bind liver-specific transcription factors.

Question 8

Which of the following mechanisms is used by eukaryotic transcription repressors to inhibit gene expression?

Accepted Answer

They can recruit enzymes that modify chromatin to make it less accessible to the preinitiation complex.

Question 9

The GAL genes in yeast are regulated by the interaction of GAL4, GAL80, and GAL3. What happens when galactose is present?

Accepted Answer

Galactose binds GAL3, which then binds GAL80, releasing GAL4 to activate transcription.

Question 10

Which of the following is a property of steroid hormone receptors that allows them to regulate gene expression?

Accepted Answer

They have a ligand-binding domain that binds hormone, a DNA-binding domain, and a transcription activation domain.

Question 11

Which of the following best describes the function of the Mediator complex in eukaryotic transcription?

Accepted Answer

It acts as a bridge between transcription activators and RNA polymerase II, facilitating assembly of the preinitiation complex.

Question 12

A mutation that prevents the addition of a 5' cap to eukaryotic mRNA would most likely result in which of the following?

Accepted Answer

Reduced stability and translation of the mRNA.

Question 13

Which of the following is TRUE regarding the organization of eukaryotic genomes compared to prokaryotic genomes?

Accepted Answer

Eukaryotic genomes have larger genes with introns and extensive regulatory regions.

Question 14

Which of the following best explains how eukaryotic cells can express different genes in different cell types?

Accepted Answer

Different cell types express different sets of transcription factors that bind to cell-type specific enhancers.

Question 15

Which of the following is a correct statement about the default state of most eukaryotic genes?

Accepted Answer

The default state is 'off' due to chromatin structure repressing transcription initiation.

Question 16

A steroid hormone enters a target cell and binds its receptor. What is the next step in activating gene expression?

Accepted Answer

The hormone-receptor complex releases from HSP90, enters the nucleus, and binds a specific DNA response element.

Question 17

Which of the following is a multi-step process unique to eukaryotic gene expression, not found in prokaryotes?

Accepted Answer

Pre-mRNA processing including 5' capping, splicing, and polyA tail addition.

Question 18

Which of the following best describes the function of insulator sequences in eukaryotic genomes?

Accepted Answer

They prevent enhancers from activating the transcription of nearby unrelated genes.

Question 19

Which of the following equations correctly represents the relationship between the number of genes and genome size in E. coli and humans?

Accepted Answer

$$	ext{E. coli:} \, 1 \, 	ext{gene} / 1000 \, 	ext{bp}$$

Regulation of Gene Expression in Eukaryotes

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