chapter 14

What are the three features common to most promoters that are needed for the initiation of transcription of protein coding genes in eukaryotes?

- regulatory elements- transcriptional start site- TATA box

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

A(n) ____ is a cluster of genes that are part of a single transcription unit that is under the control of a single promoter.

?

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

The enzyme ___________ is responsible for covalently attaching methyl groups to DNA.

Blank 1: DNA Blank 2: methylase or methyltransferase

Proteins that use energy from ATP hydrolysis to change the locations and compositions of nucleosomes are called ATP-dependent _______________ complexes.

Blank 1: chromatin Blank 2: remodeling

Which of the following describe the TATA box? Choose all that apply.

The TATA box is a sequence upstream of the transcriptional start site. The TATA box determines the precise starting point for transcription.

What are the three major functions of the enzymes encoded by the lac operon?

The breakdown of lactose The modification of lactose and lactose analogues The transport of lactose across the cell membrane

What is chromatin?

The complex formed by DNA and its associated proteins

The transcription of the lac operon genes is inhibited when the lac repressor protein binds to_________

The lac operator

What is the function of the genes that are expressed in the lac operon of E. coli?

The metabolism of lactose

What is cell differentiation?

The process by which cells become specialized in different types

_________are regulatory transcription factors that bind to DNA and decrease the rate of transcription.

repressors

Histone modifications primarily affect:

the degree of chromatin compaction

Chromatin-remodeling complexes may change chromatin structure in three main ways: (a) binding to chromatin and changing the positions of ,__________ (b) removing ___________ from the DNA, or (c) replacing standard histones with histone variants.

Blank 1: nucleosomes Blank 2: histones, histone, histone octamers, or octamers

What is an example of cell differentiation in humans?

Cells develop the structure and function specific to nerve cells.

Which of the following are ways by which ATP-dependent chromatin-remodeling complexes change chromatin structure?

Evicting histone octamers, thereby creating gaps where no nucleosomes are found Binding to chromatin and changing the positions of nucleosomes Changing the composition of nucleosomes by replacing standard histones with histone variants

What is the process by which a cell controls the level of expression of a specific gene or set of genes in a biological pathway?

Gene regulation

The lac operon is an example of what type of operon?

Inducible operon

What does the lac operon region contain?

Promoter, operator, and three structural genes

Regulation of prokaryotic gene expression typically involves all of the following mechanisms EXCEPT:

Regulation of RNA processing

What are silencers?

Regulatory elements that can prevent or decrease transcription.

Which of the following best describes the organization of sequences in a typical eukaryotic promoter?

Regulatory elements — TATA box — Transcriptional start site — Structural gene

_________________ are regulatory DNA elements that can prevent or decrease the rate of transcription of a gene.

Silencers FYI: Repressors are proteins that decrease gene transcription. Silencers are DNA elements to which repressors bind.

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

Which of the following are key differences between eukaryotic and prokaryotic transcriptional regulation?

The majority of genes are organized individually in eukaryotes, but are organized as operons in prokaryotes. 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.

What is the function of the genes encoded by the trp operon?

The synthesis of the amino acid tryptophan

What is the function of ATP-dependent chromatin-remodeling complexes?

They cause a change in the locations and/or compositions of nucleosomE they loosen it

Why is the lac operon considered inducible?

When allolactose is produced, this causes the transcription of the lac operon.

The molecule that serves as the inducer of the lac operon is

allolactose

In humans, a cell can become a muscle cell, kidney cell, skin cell, neuron, etc. This is an example of the process of cell____

differentiation

DNA methylation may prevent transcription by blocking a(n) ______ site or by converting ______ to a closed conformation.

enhancer ; chromatin

In eukaryotic DNA, regulatory elements known as ____________ play a role in the ability of RNA polymerase to begin transcription, thereby increasing the rate of transcription.

enhancers

Gene regulation allows bacteria to survive in response to _____ changes, such as the availability of specific nutrients.

enviormental

The morphologies of different cell types, such as skin cells and nerve cells, is strikingly different. This is due to the fact that the cells:

express different genes

True or false: In multicellular organisms, genes are regulated in the same way to ensure that gene expression levels are constant regardless of cell type or developmental stage.

false

The functional product of genes arises from what process?

gene expression.

Different cell types, such as skin cells and nerve cells, have different morphologies because ___________ are expressed and regulated in different ways in different cells.

genes

An operon that can be turned on in the presence of a small effector molecule is said to be a(n) ___________ operon.

inducible

The lac operon is said to be a(n) ___________operon because the binding of an effector molecule increases the rate of transcription

inducible

Which of the following genes encodes the lac repressor protein?

lacI

The genes found in the lac operon of E.coli are used for the metabolism of

lactose

Histone modifications can result in:

loosening of chromatin activation of transcription

Match the type of transcription factor with the proper form of transcriptional regulation.

match- neg control activator- pos control Regulatory transcription factors- Both positive and negative control

How can DNA methylation inhibit transcription?

methylation can convert DNA from an open confirmation to a closed one methylation can prevent an activator from binding to an enhancer

In E. coli, the genes required to metabolize lactose are expressed:

only when lactose is present

In the lac operon, the _______ is the DNA sequence at which the lac repressor binds.

operator

an mRNA that encodes more than one protein is called ____ mRNA

polycistronic

Repressor proteins are used for _____ control of gene expression, and activator proteins are used for _________ control of gene expression.

positive negative

The protein encoded by the lacI gene functions to:

prevent transcription of the lac operon repressor protein^^

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

What are the basic components of the lac operon?

promoter lacA lacY lacZ

Bacteria respond to changes in their environment by:

regulating their genes

Gene ____ expression, Incorrect Unavailable is the ability of cells to control the expression of genes.

regulation

The lacI gene encodes the lac ___

repressor

The most common organization of sequences for the promoter of eukaryotic structural genes is the regulatory elements, ________ box and ___________ start site.

tata transcriptional

when are the genes involved in lactose metabolism in E. coli expressed and when are they turned off

the genes for lactose metabolism are expressed when lactose is present and turned off when it is absent

The function of the protein encoded by lacI is:

to repress transcription of the lac operon

at what levels does gene regulation occur in prokaryotes?

translation transcription post translation

Match each protein expressed by the lac operon and its function in the breakdown of lactose.

β-galactosidase- break down lactose permease- transport galactoside transacetylase- modify