Biology M7 & 8
Which of the following are required for the small ribosomal subunit to be able to recognize and bind to an mRNA?
5' cap Several initiation factors Poly-A binding protein Poly-A tail
The lac operon genes are transcribed together in what order?
5'-lacZ-lacY-lacA-3'
What fields of study are included in bioinformatics?
Biology, computer science, and information technology
Select all of these that are posttranscriptional mechanisms that regulate gene expression.
Controlling mRNA stability Splicing of pre-mRNA Regulation of mRNA translation
In multicellular eukaryotes, what controls the elaboration of sex-related characteristics and behaviors?
Gene regulation
Match each eukaryotic RNA polymerase with the genes that it transcribes. RNA Polymerase I RNA Polymerase II RNA Polymerase III
Genes encoding the major ribosomal RNAs (rRNAs) Genes encoding proteins Genes encoding tRNAs and some other small RNA molecules
Eukaryotes have three RNA polymerases that are named RNA polymerase I, II, and III. Genes encoding proteins are transcribed by RNA polymerase _____. The major ribosomal RNAs are transcribed by RNA polymerase _____, while genes encoding the transfer RNAs (tRNAs) are transcribed by RNA polymerase _____.
II, I, III
How does the Xist lncRNA promote the formation of a Barr body in a human cell?
It binds the X chromosome from which it is transcribed, spreads along its length, and recruits histone modifying enzymes.
Scientists are currently exploring the possibility of targeting the quorum-sensing mechanism of pathogenic bacteria in the development of new antibiotics. What are advantages of this approach?
It might be more difficult for bacteria to develop resistance to such drugs. Quorum-sensing proteins do not resemble any human proteins.
How would the introduction of a chemical that interferes with quorum sensing help fight an infection by a pathogenic bacterium?
It might prevent pathogens from releasing toxins even though they have reached high densities.
It is induced by the presence of lactose.
Judging from this figure, which of the following statements is most likely true about gene X?
Transcription is the work of ______.
RNA polymerase
Eukaryotic promoters often contain a conserved sequence of approximately seven nucleotides that is located just upstream of the transcription initiation site. This sequence is called a(n) _____ box.
TATA
Which of the following statements about genomic imprinting is correct?
The allele of a gene inherited from one parent is transcriptionally active, and the allele from the other parent is transcriptionally inactive.
quorum sensing
This figure depicts how the mechanism of _____ _____ controls bioluminescence in Vibrio fischeri.
Select the steps at which gene regulation can occur in eukaryotes.
Transcription RNA processing Posttranslational modification Translation
What is the benefit of alternative splicing?
Two or more polypeptides can be derived from a single gene.
An epigenetic phenomenon is ______.
a heritable change in gene expression that is not caused by any type of DNA mutation
A CpG island is a DNA sequence that contains ________.
a higher than average frequency of CpG dinucleotides
An operon is a group of two or more genes under the transcriptional control of ______.
a single promoter
In Vibrio fischeri, the quorum-sensing genes are luxR, which encodes a transcriptional _____ protein and luxI, which encodes a enzyme that is used to make a molecule called a(n) _____.
activator, autoinducer
The term for the mechanism that enables two or more different polypeptide sequences to be produced from a single gene is _____ _____.
alternative splicing
Regulatory RNAs that are transcribed from the opposite DNA strand to that of the mRNA are called ______ RNAs.
antisense
Transcription begins but terminates before the entire mRNA is made during _____
attenuation
In the trp operon, the interaction between the translation machinery and a portion of the RNA leader called the _____ determines whether or not transcription will terminate prematurely.
attenuator
In this figure, the red structures represent a molecule called a(n)
autoinducer
What proteins bind to the promoter of a gene?
basal transcription factors
Because it is easy to measure the levels of ______-_______, the lacZ gene which encodes this enzyme can be used as a(n) _____ gene to detect the amount of transcription that occurs in response to any specific regulatory element.
beta galactosidase ; reporter
In order to be recognized by the small ribosomal subunit, a eukaryotic mRNA is circularized through the interaction of the poly-A _____ _____ and eIF4G.
binding protein
The positive regulator of the lac operon is the ______ _______ protein (CRP).
cAMP, receptor
The methylation of DNA at imprinting control regions (ICRs) ______.
can either activate or repress transcription
Breakdown of sugars occurs via ______ pathways, whereas the synthesis of amino acids occurs via ______ pathways.
catabolic; anabolic
Antisense RNA is an RNA strand that is _____ to an mRNA molecule.
complementary or reverse-complementary
When DNA in a human cell is methylated, methyl groups are added to some _______.
cytosines
Positive regulation and negative regulation typically refer to mechanisms that _____.
enhance or inhibit RNA polymerase activity, respectively
The genes in the trp operon encode ______.
enzymes used in tryptophan biosynthesis
Any heritable, self-perpetuating change in gene expression that is not caused by DNA mutation is a(n) _____ phenomenon.
epigenetic
According to the parental conflict hypothesis, imprinting in mammals occurs as a way to balance the _______.
father's interest in producing large babies with the mother's need to balance her needs with the needs of the fetus.
The Tra protein regulates the splicing of the _____ and _____ primary transcripts.
fru or fruitless, dsx or doublesex
Which of the following genes encode primary RNAs whose splicing is regulated by the Tra protein?
fruitless (fru) doublesex (dsx)
The cAMP receptor protein (CRP) _______ of the lac operon.
functions as an activator
In order to use lacZ as a reporter gene, scientists use recombinant DNA technology to create a _____ gene which contains the coding region of lacZ and the cis-acting regulatory regions of a different gene.
fusion
The synthesis of RNAs and proteins according to the instructions encoded in DNA is a process called ______.
gene expression
In order for imprinting patterns to be reset and passed on to the next generation in a sex-specific way, the methyl groups on DNA must be removed and then replaced on the DNA in ______.
germ-line cells
Prader-Willi syndrome and Angelman syndrome are examples of human developmental disorders associated with _______.
imprinting
The phenomenon in which the expression of an allele depends on which parent transmits it is known as genomic _____
imprinting
Programmed epigenetic phenomena occur ______
in all individuals of a species
The addition of lactose to a bacterial medium causes a 1000-fold increase in the synthesis of the two proteins Lac permease and β-galactosidase. This phenomenon is termed _______.
induction
The process by which a specific molecule stimulates synthesis of a given protein is called ______
induction
A DNA element that organizes chromatin so that enhancers have access only to particular promoters is called a(n)
insulator
Which Vibrio fischeri genes encode the quorum-sensing proteins?
luxI luxR
Genomic imprinting patterns are erased and then reestablished in a sex-specific way as germ-line cells go through _____.
meiosis
The three classes of small regulatory RNAs that have been identified are ____.
miRNA, siRNA, and piRNA
When a new daughter cell is produced in mitosis, most genes that were off in the mother cell ______.
must "learn" that they should be off after mitosis is completed, depending on the presence of specific transcription factors in the cell
The inhibition of RNA polymerase activity is termed ______ regulation, whereas the enhancement of RNA polymerase activity is known as _____ regulation.
negative, positive
The lac operon control region can help produce protein drugs in bacteria. The first step in this process is the creation of a recombinant plasmid in which the lac regulatory region is fused to the _____ _____ _____ encoding the protein to be expressed.
open reading frame
A(n) _____ is a group of two or more genes under the transcriptional control of a single promoter
operon
One of the explanations for why imprinting occurs in mammals is that it balances the paternal interest in fathering large, robust babies with the maternal need to balance resources between herself and the developing fetus. This is called the_____ _____ hypothesis.
parental conflict
The lac operon structural genes are transcribed as _____.
part of a single polycistronic mRNA with three independent ribosome binding sites
In many organisms, cells can transmit information about the silenced transcriptional status of particular genes to their daughter cells through mitosis, but not to subsequent generations of individuals through the gametes. The transmission of these cellular "memories" occurs in all individuals of a species and is therefore said to be _____.
programmed
Basal transcription factors bind to ______.
promoter
In multicellular eukaryotes, the differentiation of tissues and organs is controlled by gene _____.
regulation
When Dsx-M binds to an enhancer upstream of the yp1 gene, transcription of yp1 is _____. When Dsx-F binds to the same enhancer, transcription of yp1 is _____.
repressed, activated
To initiate translation, ribosomes attach to the mRNA at a site called the ____ - _____ site.
ribosome-binding or Shine-Dalgarno
Which of the following types of RNA are small regulatory RNAs that affect the expression of other genes?
small interfering RNAs (siRNAs) micro-RNAs (miRNAs) Piwi-interacting RNAs (piRNAs)
Constitutive mutants ______.
synthesize certain proteins all the time
In Drosophila, sex is determined by the _____.
the number of X chromosomes
Ribosome profiling is conceptually similar to DNA footprinting in that it identifies locations on mRNA where ribosomes are bound because ______.
those RNA sequences are protected from digestion with RNase
DNA methylation at different imprinting control regions (ICRs) can either repress or activate the _____ of nearby genes.
transcription or expression
The base sequences of all the RNAs that a cell produces under a particular set of conditions is known as the _____
transcriptome
The entire set of RNAs produced by a cell is called its ______.
transcriptome
Small RNA (sRNA) molecules regulate _____.
translation in trans by base-pairing with mRNAs
In Drosophila, the activation of transcription of the Sxl gene during embryogenesis requires the presence of _____.
two X chromosomes
The ribosome-binding site is a special initiation site located ______.
upstream (near the 5' end) of the open reading frame
The development of a fruit fly as male or female is determined by the number of _____ chromosomes that are present.
x
The normal housekeeping sigma factor is _______.
σ70
Which of the following are mechanisms that ensure that certain genes that were off in a parental cell will remain off in daughter cells after mitosis?
Certain histone modifications that repress transcription are copied inefficiently at the replication fork. Certain activators and repressors are retained in the daughter cell cytoplasm.
Stretches of DNA up to a few thousand bp in length that contain a high number of CpG dinucleotides are called _____ _____
CpG Islands
The addition of a methyl (-CH3) group to the cytosine in a 5' CpG 3' dinucleotide pair is called _____ _____
DNA Methylation
Which version(s) of the Dsx protein will activate transcription of the yp1 gene?
Dsx-F only
There are two versions of the Drosophila Doublesex protein: Dsx-M and Dsx-F. How would you expect a gene that promotes the development of male sexual characteristics to be affected by Dsx?
Dsx-M would activate the gene, but Dsx-F would repress it.
Which of the following statements best describes gene regulation in multicellular eukaryotes?
Each gene may contain several enhancer elements each with binding sites for several different transcription factors.
Where is the TATA box of a eukaryotic gene located?
In the promoter
How can gene regulation mechanisms be limited to only a particular gene and not its neighbors?
Insulators between genes organize chromatin and limit enhancer access to promoters.
Which of the following human disorders involve mutations of imprinted genes?
Prader-Willi syndrome Angelman syndrome
If gene regulation occurs at the level of translation such that translation is stopped, what molecules in the pathway will NOT be produced?
Protein Phosphorylated protein
______ is a bacterial communication system that allows them to adjust their behavior according to their population density.
Quorum sensing
The enzyme that transcribes a gene's DNA into RNA is called _____ _____.
RNA Polymerase
How do the wild-type and peloria alleles of the Lcyc gene in toadflax differ?
The peloria allele is extensively methylated.
What is required for activation of transcription of the Sxl gene during embryogenesis in Drosophila?
The presence of two X chromosomes
How are the two sigma factors σ70 and σ32 in E. coli different from each other?
They bind to different promoter sequences. They denature at different temperatures.
Choose all statements that describe nonprogrammed epigenetic phenomena.
They occur by chance. They occur in response to specific environmental influences.
The field of science that combines biology, computer science, and information technology into a single discipline is called
bioinformatics
A(n) _____ mutant is an organism that synthesizes certain proteins all the time, regardless of environmental conditions.
constitutive
In fruit flies and humans, one possible mechanism for a weak cellular memory of heterochromatin is the propagation of a histone mark in which the K9 amino acid on the tail of H3 is ______.
methylated
The enhancer of a eukaryotic gene may interact with _______.
several different activators and repressors that bind to the enhancer with varying affinities
Splicing of pre-mRNA, altering mRNA stability and controlling the rate of translation are all examples of ______.
posttranscriptional gene regulation
In ribosome profiling, the location of ribosomes along mRNAs are determined based on the fact that _____.
ribosomes protect from RNA nucleases sequences to which they are bound
The term sRNAs refers to ____ RNA molecules that regulate translation by base-pairing with mRNAs in bacteria.
small
Select the genes in the trp operon.
trpE trpC trpA trpD trpB
