Mbios 301 exam 2 book questions
DNA methyltransferase
5-methylcytosine is formed by ______.
cis acting
A DNA segment that must be adjacent to the gene(s) it regulates is a __________ ____________ element.
nucleosomes
A change in chromatin confirmation from closed to open often involves the movement of ______.
nuclear lamina
A fibrous layer of proteins lining the inner nuclear membrane of eukaryotic cells is called the ______.
operon
A group of two or more genes under the transcriptional control of a single promoter is called a(n) ___________.
Transcription factor
A protein that influences the ability of RNA polymerase to transcribe DNA into RNA is called a(n)
allosteric
A regulatory site on a protein where an effector molecule binds is called a(n) _________ site.
merozygote
A strain of bacteria containing F' factor genes is called a(n) _______ or a partial diploid.
upregulation
An enhancer is a DNA element that is bound by a regulatory transcription factor, which leads to ______.
a single promoter.
An operon is a group of two or more genes under the transcriptional control of ______.
repressible; inducible
Anabolic enzymes are usually encoded by ______ operons, and ______ operons usually encode catabolic enzymes.
complementary
Antisense RNA is an RNA strand that is _________ to an mRNA molecule.
higher-order
Any assemblage of nucleosomes that assumes a reproducible confirmation in three-dimensional space represents a(n) __________-____________ structure.
non coding
Besides DNA and histone proteins, ___________-__________ RNAs are a critical component of chromatin.
feedback inhibition
Consider a case where the end product of a metabolic pathway inhibits an enzyme that acts early on in the pathway. This mechanism of regulation is called ____________ _______________
Posttranslational
Control of proteins already present in the cell is called ___________ regulation.
covalent
DNA methylation is the ___________ attachment of methyl groups to DNA.
epigenetic
DNA methylation, chromatin remodeling, covalent histone modification, and localization of histone variants are all molecular mechanisms that contribute to ___________ gene regulation.
but is terminated before the entire mRNA is made
During attenuation, transcription begins ______.
constitutive, facultative
During cell division, from M phase in the mother cell to interphase in the resulting two daughter cells, a chromosome will usually retain the same pattern of ____________ and _______________ heterochromatin that was found in the mother cell.
epigenetic
During embryonic development, many genes undergo ____________ changes that enable them to be transcribed or cause them to be permanently repressed.
constitutive
Heterochromatic regions found in the same locations in all cell types are called ______ heterochromatin.
Transcription factors recruit chromatin modifying proteins, such as DNA methyltransferase.
How do transcription factors contribute to epigenetic modification?
methylated nonmethylated
If fully methylated DNA is introduced into a plant or animal cell, in subsequent generations the DNA will be ___________. If the same sequence of nonmethylated DNA is introduced into a cell, it will be __________ in daughter cells.
transferrin
In animals, the major protein that carries iron in the bloodstream is ______.
is stopped prematurely
In attenuation, transcription ______.
rate of transcription initiation
In bacteria, the most common way to regulate gene expression is by influencing the ______.
glucose
In catabolite repression, transcription is influenced by the presence of ______.
5 cytosine
In eukaryotes, DNA methyltransferase is an enzyme that attaches a methyl group to the __________ position of the __________ base.
transposable element movement transcription viral proliferation
In eukaryotic cells, which processes are prevented by heterochromatin formation?
lamina
In most eukaryotic cells, the inner nuclear membrane of the cell is lined by a fibrous layer of proteins called the nuclear
variants
Most histone genes encode standard histone proteins, but some have accumulated mutations that change the amino acid sequence of the histone proteins. These proteins are called histone ___________
RNA molecules that do not encode polypeptides
Non-coding RNAs are ______.
H2A.Z H2A
Nucleosomes containing the histone variant ____________, which are usually found at the +1 nucleosome, are thought to be more easily removed from the DNA than those containing the standard histone ________.
receptor
Once inside the cell, the glucocorticoid hormone binds to a glucocorticoid ______, releasing it from a protein known as HSP90.
1) binding of an activator to an enhancer in the NFR 2) recruitment of a chromatin-remodeling complex and a histone-modifying enzyme 3) recruitment of general transcription factors and RNA polymerase II to the core promoter allowing the formation of a preinitiation complex 4) eviction or destabilization of histone octamers, allowing RNA polymerase II to pass and elongation to occur
Place these steps in a simplified model for transcriptional activation of a eukaryotic gene in order, with the first step at the top.
control of proteins already in the cell
Posttranslational regulation refers to ______.
non-coding
RNA molecules that do not encode polypeptides are called ____________-____________ RNAs.
facultative
Regions of heterochromatin that vary among different cell types are called ______________ heterochromatin.
attenuation
Regulation of the trp operon involves the process of __________ in which transcription begins but terminates before the entire mRNA is made.
three
Studies indicate that the lac operon has ______ operator site(s) for the lac repressor.
TATA promoter
TFIID binds to the __________ box and helps recruit RNA polymerase II to the core _______
nucleosome, DNA, histone
The basic repeating unit of chromatin is the _________, composed of ____________ wrapped around an octamer of ____________ proteins.
enhancer up
The binding of a regulatory transcription factor to a(n) __________ can stimulate transcription 10- to 1000-fold, which is called _________ regulation.
nucleosome-free region
The core promoter of active genes is found in a(n) ________-free _________ which is a segment of DNA that is missing histones.
methylation
The covalent attachment of a -CH3 group to DNA is known as DNA ______.
bind to the TATA box and recruit RNA polymerase II to the core promoter
The function of TFIID is to ______.
at the proper time under the appropriate environmental conditions in the correct cell type
The function of regulatory transcription factors must be modulated to ensure that genes are turned on ______.
enzymes used in tryptophan biosynthesis
The genes in the trp operon encode ______.
HOTAIR
The ncRNA Hox transcript antisense intergenic RNA is also known as _________________
adaptation
The observation that a particular enzyme appears within a cell only after a cell has been exposed to the enzyme's substrate is called enzyme __________
regulation
The phenomenon in which the level of gene expression can vary under different conditions is gene ________
regulation
The phenomenon where gene expression is controlled so that genes can be expressed at high or low levels is called gene ___________
dependent chromatin
The process that uses the energy of ATP hydrolysis to change the position or composition of nucleosomes is called ATP- ____________ ____________ remodeling.
catabolite repression
The somewhat imprecise term that describes how transcriptional regulation is influenced by glucose is ____________ ____________
controlling the switch from the initiation to the elongation stage of transcription regulating the binding of the transcriptional complex to the core promoter
Transcription factors that affect the ability of RNA polymerase to begin the transcription process may work by ______.
False
True or false: Gene expression is always the same.
False
True or false: Gene regulation may be related to epigenetic events such as the binding of transcription factors to certain genes, which induce permanent mutations in the DNA.
False
True or false: On a regulatory protein, an allosteric site is the same as the active site.
True
True or false: The function of regulatory transcription factors is modulated in order to control the timing of gene expression.
True
True or false: The methylation state of DNA is inherited during cell division.
False
True or false: The rate of transcription initiation rarely influences overall gene expression.
H1, H2A, H2B, and H3
Variants have been identified for which of the following histones?
epigenetics
Variation of gene expression that is transmissible and reversible but not related to the variation in the DNA is called
antisense RNA
What do you call an RNA strand that is complementary to an mRNA molecule?
both activation and repression
What effect can ATP-dependent chromatin remodeling have on transcription?
merozygote
What is the name for a strain of bacteria containing an F' factor?
150 bp
What is the size of the nucleosome-free region found at the core promoter of active genes?
Trans-acting factor
What type of regulator does not need to be adjacent to the gene(s) it is regulating?
makes the Shine-Dalgarno sequence available to the ribosome
When TPP levels are low, the mRNA of the E. coli thiMD operon forms a stem-loop structure that ______.
nucleosome
Whether a gene is active or inactive often depends on the placement of __________ at or near its promoter region.
scaffold, guide, protein function or stability, ribozyme, blocker, decoy
Which functions are commonly carried out by ncRNAs?
trpA, trpB, trpC, trpD, and trpE
Which genes in the trp operon encode enzymes involved in tryptophan biosynthesis? hint there's 5
splicing, transcription, RNA stability, and translation
Which of the following can be regulated by riboswitches?
preventing movement of transposable elements preventing viral proliferation silencing genes
Which of the following represent key functional roles for heterochromatin in eukaryotic cells?
30-nm fiber
Which of the following represents a higher-order structure found in chromatin?
X-chromosome inactivation in female mammals
Which of the following represents a programmed epigenetic change that occurs during development?
DNA, RNA, proteins, and small molecules
ncRNAs commonly bind to which of the following molecules?
scaffold
what role is played by the ncRNA?
gene expression can be controlled so that genes can be expressed at high or low levels
Gene regulation means that ______.
epigenetic changes that enable specific genes to be transcribed epigenetic changes that cause specific genes to be permanently repressed
Identify changes that can occur during embryonic development that will lead to a pattern of differential gene expression unique to a specific cell type.
Translation
If a riboswitch controls access to the Shine-Dalgarno sequence, which of the following will be regulated?
inhibits an enzyme that acts early in the pathway
In feedback inhibition, the final product in a metabolic pathway ______.
Barr
In somatic cells of female mammals, one of the two X chromosomes becomes a condensed _____________ body, where the genes are inactivated.
somatic; female
X-chromosome inactivation occurs in ______ cells of ______ mammals.
a particular enzyme appears within a cell only after the cell has been exposed to the substrate for that enzyme
Enzyme adaptation refers to the observation that ______.
ferritin
Excess iron in animal cells is stored within a hollow, spherical protein known as
operator
It has been shown that the lac operon has three ________ sites to which the lac repressor can bind.
acetyltransferases
Lysine residues on core histone proteins can be acetylated by enzymes called histone
gametogenesis embryogenesis
Many epigenetic modifications are programmed changes that occur during developmental stages such as __________ or __________.
imprinting control, differentially methylated
This figure shows the region of a chromosome that contains the Igf2 and H19 genes in mammals. ICR refers to _________ __________ region, while DMR stands for __________ ___________region.
DNA methylation localization of histone variants covalent histone modification chromatin remodeling
Which of these are molecular mechanisms that underlie epigenetic control of gene expression?
Epigenetic changes may be transmitted to offspring. Variations of gene expression are unrelated to variations in the DNA base sequence. Variations are reversible from one generation to the next. Epigenetic changes are transmissible from cell to cell.
Which of these are true regarding epigenetics?
causes attenuation
In the thi operon in B. subtilis, when levels of TPP are high, the mRNA folds into a stem-loop structure that ______.
antiterminator
In the thi operon in B. subtilis, when levels of TPP are low, the 5' end of the mRNA forms a stem-loop structure called a(n) _______________ that allows transcription to continue.
histone acetyltransferase
Which type of enzyme can add acetyl groups onto the lysines of core histone proteins?
antisequestor
In the E. coli thiMD operon, the 5' end of the mRNA folds into a structure with a stem-loop called the Shine-Dalgarno _______________ that keeps the Shine-Dalgarno sequence accessible to the ribosome.
attenuation
The trp operon is regulated by a repressor protein and by _____________ in which transcription is stopped prematurely.
