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