Solutions
1. are boundary elements that function to prevent the enhancer
for one gene from activating the promoter of another gene.
2. are DNA sequences that can prevent packaging of a gene into
heterochromatin.
3. require the zinc-finger protein CTCF to function in higher
eukaryotes. Correct Answers Insulators:
1. Be devoid of nucleosomes
2. be deficient in histone H1.
3. contain sites hypersensitive to in vitro treatment with DNase
I. Correct Answers Transcriptionally active chromatin tends to:
1. Gene promoters are essentially inactive in the absence of
regulatory proteins.
2. Access to promoters is restricted by the structure of
chromatin.
3. Virtually every gene requires activation. Correct Answers
What are characteristics of the transcriptional ground state in
higher eukaryotes?
1. homeodomain
2. leucine zipper
3. helix-turn-helix Correct Answers What structural motifs are
commonly found in the DNA-binding motifs of proteins that act
as transcriptional regulators?
1. It contains several evenly spaced leucine residues that make
specific DNA contacts.
, 2. It is made up of a single alpha-helix.
3. It is only found in bacterial proteins. Correct Answers Which
of the following is NOT true of the leucine-zipper structural
motif?
1. Modification leads to chromatin condensation.
2. The RNA polymerase associated with the gene dissociates
from DNA when HDACs (Histone deacetylases) bind to the
corepressor.
3. Increased methylation of the nucleosomes occurs in the
vicinity of the gene. Correct Answers What is generally
involved in gene inactivation by histone modification?
1. Moving nucleosomes could cover a promoter resulting in
repression of transcription.
2. Moving nucleosomes could expose a promoter resulting in
activation of transcription. Correct Answers How can
repositioning nucleosomes affect transcription?
1. Specific factors are used to direct the polymerase to bind a
specific type of promoter sequence.
2. Abortive transcripts are formed prior to the elongation phase.
3. RNA polymerase interacts with DNA upstream from the
coding sequence in the template.
4.Transcription has distinct initiation, elongation, and
termination phases. Correct Answers What is true of both
bacterial transcription and eukaryotic transcription?
1. The 70S ribosome is a complex of 50S and 30S subunits.
2. Each ribosomal subunit contains at least one RNA molecule