SB Chapter 14
The two nucleosomes flanking the NFR are termed ____ and _____.
-1; +1
A nucleosome-free region is typically about ______ in length.
150 bp
For initiation of eukaryotic transcription at the core promoter, three types of proteins are needed: RNA polymerase _____ , GTFs, and a large protein complex called ______.
2; mediator
Eukaryotes have ______ forms of RNA polymerases.
3
In mammals, approximately Blank______ of the DNA is methylated.
5%
Eukaryotic Structural Genes
A- Regulatory Elements B- Promoter C- Core Promoter D- TATA Box E- Transcriptional Start Site
How does gene regulation help conserve energy for an organism?
By only expressing the gene product when it is needed in the cell
How can faster regulation of gene expression be achieved in eukaryotes?
Controlling the steps in RNA processing Controlling the steps after an RNA is made
Methylated sequences attract a specific group of proteins, which when bound to DNA, recruit other proteins to the region that inhibit transcription. These DNA-attaching proteins are known as methyl-_____-binding proteins.
CpG
In vertebrates and flowering plants, many genes contain DNA sequences called Blank______ near their promoters that remain unmethylated.
CpG islands
The enzyme responsible for covalently attaching methyl groups to DNA is ___ ____
DNA methylase
What are regulatory elements?
DNA segments that can enhance or prevent transcription of eukaryotic genes
Regulatory elements are best defined as ______.
DNA segments that regulate eukaryotic genes
When and where might alternatively spliced gene products occur?
During different stages in animal development In different tissues in an animal
What is the function of general transcription factors (GTFs) in the initiation of transcription?
GTFs and RNA polymerase come together at the core promoter for the initiation of transcription
______ bind to the core promoter and are required for the initiation of transcription, while ______ bind to enhancers and regulate the function of RNA polymerase through interactions with other proteins. Multiple choice question.
GTFs; activators
During transcription in eukaryotes, the preinitiation complex forms at the TATA box. It is composed of RNA polymerase II and _____ . Another component needed for transcription in eukaryotes is a group of proteins called _____ complex. It partially wraps around the preinitiation complex.
GTFs; mediator
What proteins can bind to methylated DNA sequences and recruit other proteins that inhibit transcription?
Methyl-CpG-binding proteins
How can DNA methylation inhibit transcription?
Methylation can alter chromatin structure. Methylation can prevent an activator from binding to an enhancer.
Which eukaryotic RNA polymerase transcribes structural genes that encode proteins?
RNA Polymerase II
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
Match each protein or group of proteins with its role in transcription. Instructions
RNA polymerase- synthesis of RNA from a DNA template GTFs- required for binding to the core promoter and initiating transcription Activators- binding to enhancer sequences and interaction with other proteins
What molecules can influence transcription by binding to enhancers or silencers?
Repressors and activators
What are the two components of the core promoter?
TATA box Transcriptional Start Site
The two components that make up the core promoter are the _______ box and the transcriptional start _____.
TATA; site
How does the mediator protein interact with RNA polymerase and the GTFs during the initiation of transcription?
The mediator protein controls interactions between the pre-initiation complex and other regulatory elements.
Which is a result of alternative splicing?
The proteome size is increased and the genome size is minimized.
A nucleosome-free region (NFR) is
a site on a chromosome that is missing nucleosomes
How do activators and repressors regulate the function of RNA polymerase in eukaryotes?
activators and repressors interact with GTFs or mediator complex
Small effector molecules exert their effects by binding to two types of regulatory transcription factors: ______ and ______ . This binding causes conformational changes in these proteins that affect their ability to bind to DNA.
activators; repressors
Humans have only about 22,000 different protein-coding genes, yet their cells make well over 100,000 different polypeptides. This is due to the phenomenon of _____ _____ , which is much more prevalent in complex eukaryotic species.
aleternative splicing
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
In this schematic of the promoter of a eukaryotic structural gene: label C represents the _____ _______ , while label E represents the transcriptional _____ _____.
core promoter; start site
Eukaryotic DNA methylation typically occurs on the base
cytosine
In eukaryotes, which base is commonly methylated in DNA?
cytosine
Some proteins are produced only when needed. This is an example of gene regulation that conserves _______
energy
DNA methylation may prevent transcription by blocking a(n) Blank______ site or by altering the structure of Blank______.
enhancer ; chromatin
Gene regulation allows bacteria to survive in response to _______ changes, such as the availability of specific nutrients.
environmental
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 ______
expression
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
Many eukaryotic genes are flanked by a site that is missing nucleosomes. This site is known as a nucleosome- ____ _____ .
free region
The functional product of genes arises from what process?
gene expression
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
Multicellular organisms ensure that most proteins are produced at appropriate times and in appropriate cell types via the regulation of the _______ that encode these proteins.
genes
The nucleosomes flanking the NFR often contain ______.
histone variants
What are the three types of proteins that play a role in initiating transcription at the core promoter of eukaryotic structural genes?
mediator complex GTFs RNA polymerase II
Which of the following is a common modification that affects the structure of DNA?
methylation
What are small effector molecules?
molecules that bind to transcription factors and change their conformation
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.
processing
One benefit of regulating RNA processing in eukaryotes is the ability to Blank______.
produce more than one mRNA from a single gene
For active genes or those genes that can be activated, the associated nucleosome-free region (NFR) contains the core _____.
promoter
Regulatory transcription factors influence the expression of genes by affecting the rate of transcription. They do so by binding directly to DNA at or near the _______ site.
promoter
Which of the following are similarities between eukaryotic and bacterial transcriptional regulation?
proteins are the ability of RNA polymerase to bind to the DNA small effector molecules are involved in gene regulation
What are regulatory transcription factors?
proteins that bind to DNA and affect the transcription of one or more genes
Bacteria respond to changes in their environment by
regulating their genes
The ability of cells to control the expression of genes is termed gene ______
regulation
Regulation of bacterial gene expression typically involves all of the following mechanisms except ______.
regulation of RNA processing
Methylated CpG islands are usually associated with Blank______ genes, whereas unmethylated CpG islands are usually associated with Blank______ genes. Multiple choice question.
repressed; active
How can gene regulation be specific?
specific genes are expressed at different developmental stages specific genes are expressed only in certain cells specific genes differ in expression levels from cell to cell
What are two major benefits of gene regulation?
the conservation of energy expression of genes at appropriate times
Which of the following are key differences between eukaryotic and bacterial transcriptional regulation?
the majority of genes are organized individually in eukaryotes, but are organized as operons in bacteria the complexity of eukaryotic development requires that transcription be more coordinated and integrated than in bacteria combinatorial control of gene expression is more common in eukaryotes
What is the role of small effector molecules in transcriptional control?
they bind to transcription regulatory factors and alter how they bind to DNA
Small effector molecules bind to certain proteins and cause conformational changes that influence the ability of these proteins to bind to DNA. Such proteins are called regulatory ______ factors.
transcription
Eukaryotic gene expression can be regulated at which levels?
transcription RNA modification translation
At what levels does gene regulation occur in bacteria?
transcription translation post-translation
DNA methylation is common in which eukaryotes?
vertebrates and plants