Bio Ch 14
Eukaryotic gene expression can be regulated at which levels?
RNA modification translation transcription
The lac repressor protein prevents the enzyme ____from transcribing the genes in the lac operon.
RNA polymerase
Why are interactions between RNA polymerase II and GTFs important for transcription in eukaryotes?
RNA polymerase II and GTFs must interact for the polymerase to bind properly at the core promoter site of the DNA.
In eukaryotes, the core promoter, by itself, results in low levels of transcription that is known as____transcription.
basal
hemoglobin
is the main protein that delivers oxygen to cells of a mammal's body.
Histone modifications can result in:
loosening of chromatin activation of transcription
Bacteria and eukaryotes can regulate genes at the level of transcription. In eukaryotes, gene expression is also commonly regulated at the levels of RNA ___and translation
modification
In the lac operon, the _______ is the DNA sequence at which the lac repressor binds.
operator
The lacO site of the lac operon is called the ____and is the site where the repressor protein binds.
operator
The catabolite activator protein (CAP) is involved in ______ control of the lac operon.
positive
Regulatory transcription factors influence the expression of genes by binding directly to DNA at or near the _____ site and affect the rate of transcription.
promoter
Regulation of prokaryotic gene expression typically involves all of the following mechanisms
regulation of translation; regulation of transcription; modifications to proteins after translation
RNA polymerase
synthesis of RNA from a DNA template
What is an operon?
A cluster of genes under the transcriptional control of a single promoter
What is cyclic AMP (cAMP)?
A small effector molecule involved in the positive control of the lac operon
What is an inducer?
A small effector molecule that increases the rate of transcription
Which of the following are key differences between eukaryotic and prokaryotic transcriptional regulation?
Combinatorial control of gene expression is more common in eukaryotes. The complexity of eukaryotic development requires that transcription be more coordinated and integrated than in prokaryotes. The majority of genes are organized individually in eukaryotes, but are organized as operons in prokaryotes.
only when lactose is present
In E. coli, the genes required to metabolize lactose are expressed:
The lac operon is an example of what type of operon?
Inducible operon
What are regulatory transcription factors?
Proteins that bind to DNA and affect the transcription of one or more genes
Which of the following are similarities between eukaryotic and prokaryotic transcriptional regulation?
Small effector molecules are involved in gene regulation. Proteins influence the ability of RNA polymerase to bind to the DNA.
energy
Some proteins are produced only when needed. This is an example of gene regulation that conserves
What are the two components of the core promoter?
TATA box transcriptional start site
DNA and its associated proteins form a compact structure called:
chromatin
Transcription of the trp operon is ______ when levels of tryptophan are low in the cell.
increased
An operon that can be turned on in the presence of a small effector molecule is said to be a(n) __ operon
inducible
The trp operon is regulated by a(n) ____protein that is encoded by the trpR gene.
repressor
general transcription factors
required for binding to the core promoter and initiating transcription
The two components that make up the core promoter are the___box and the transcriptional start___
tata; site
In order for transcription of protein coding genes in eukaryotes to begin, the promoter must have several key features. What are they?
TATA box, regulatory elements, transcriptional start site
What is the role of the corepressor in the expression of the trp operon?
The corepressor binds to the repressor protein and causes a conformational change, which allows the repressor to bind to the operator site.
gene expression
The functional product of genes arises from what process? The process in which the information in a gene is made into a functional gene product, such as an RNA molecule or a protein, is termed gene
What is cell differentiation?
The process by which cells become specialized in different types
The binding of the corepressor to the trp repressor results in what?
The repressor binds to the operator and prevents transcription.
What is the role of the repressor protein in the transcription of the trp operon?
The repressor protein binds to the operator site and prevents the transcription of the trp operon.
What is the CAP site for the lac operon?
The sequence of nucleotides that is recognized by an activator protein
The metabolism of lactose
What is the function of the genes that are expressed in the lac operon of E. coli?
In eukaryotes, the rate of transcription of genes is influenced by regulatory transcription factors called___.These proteins bind to regulatory elements and control the gene expression rate.
activators and repressors
When the sugar___binds to the repressor protein, this causes a conformational change that prevents the repressor from binding to the ___site
allolactose; operator or lacO
The process whereby different transcripts are made from a single gene is called
alternative splicing
Which of the following is a form of gene regulation in which a eukaryotic pre-mRNA can be processed to produce more than one mature RNA?
alternative splicing
activators
binding to enhancer sequences and interaction with other proteins
What small effector molecule is involved in the activation of the lac operon when glucose is absent?
cAMP
Proteins that use energy from ATP hydrolysis to change the locations and compositions of nucleosomes are called ATP-dependent ___ complexes
chromatin-remodeling
The enzyme____is responsible for covalently attaching methyl groups to DNA.
dna methyltransferase
Polycistronic mRNA:
encodes more than one protein
Many eukaryotic genes are flanked by a nucleosome-_____which is a site that is missing nucleosomes.
free region
The transcription of the lac operon genes is inhibited when the lac repressor protein binds to:
the lac operator
The function of the protein encoded by lacI is:
to repress transcription of the lac operon
In mammals, iron toxicity is prevented by regulating the ______ of ferritin.
translation
The genes in the trp operon encode enzymes that make the amino acid
tryptophan
The transcription of the trp operon is turned off when there are high levels of ____in the cell
tryptophan