Molecular Genetics Final
Even though living organisms can be highly conserved in gene sequence and functional metabolism, one reason there are major differences in the organisms themselves is
- because all the exact same genes are expressed amongst different organisms - because timing of gene expressions is highly conserved amongst organism -because location of expression is specific to different organism
Our understanding of molecular genetics has furthered our understanding of genes and their functions by
-allowing scientists to add a specific regulation method of a gene to be placed in front of visual reporter protein -allowing scientists to locate a specific gene location that was affected in a mutant phenotype -all of these answers -allowing scientists to specifically mutate sites within a single gene -allowing scientists to recombine genetic sequence to observe the resulting proteins new function
The position effect variegation (PEV) phenotype described in this chapter can be used to identify new genes that regulate heterochromatin formation. For instance, strains of Drosophila melanogaster with the White variegation phenotype have been subjected to mutagenesis to screen for dominant mutations (in other genes) that either enhance or suppress PEV, meaning the mutations result in either lower or higher red pigment production, respectively. Which of the following mutations is expected to be an enhancer of variegation? --A mutation that results in the loss of function of the fly's HP1 (heterochromatin protein 1) gene. --A gain-of-function mutation in a gene encoding a histone methyl transferase that trimethylates lysine 9 on histone H3, resulting in a hyperactive form of the enzyme. --A gain-of-function mutation in a gene encoding a histone acetyl transferase that normally acetylates lysine 9 on histone H3, resulting in higher expression of the protein. --A loss-of-function mutation in a gene encoding a histone deacetylase that deacetylates lysine 9 on histone H3.
A gain-of-function mutation in a gene encoding a histone methyl transferase that trimethylates lysine 9 on histone H3, resulting in a hyperactive form of the enzyme.
The nucleolus is a dynamic subcompartment within the nucleus and its size varies depending on the circumstances. In which of the following cells would you NOT expect to see the nucleoli? A mouse embryonic cell in the metaphase stage of mitosis A human neuron in a quiescent (G0) state A human macrophage active in phagocytosis A fruit fly embryonic nucleus in the G2 phase of the cell cycle A yeast cell undergoing DNA replication
A mouse embryonic cell in the metaphase stage of mitosis
Several mechanisms contribute to the diversity of the mRNAs and proteins encoded by a single gene in our genome. Which of the following is normally NOT one of them? Alternative choice of transcription initiation sites Alternative choice of translation initiation sites Alternative choice of splice sites Alternative choice of the reading frames Alternative choice of polyadenylation sites
Alternative choice of the reading frames
A portion of RNA-seq data obtained from two tissue samples is plotted in the following schematic diagram. Which region (A to E) corresponds to an alternative exon? A B C D E
D
Which of the following schematic drawings better depicts the end of mammalian chromosomal DNA? B D C A E
D
What group of mobile genetic elements is largely responsible for the resistance of the modern strains of pathogenic bacteria to common antibiotics? Retroviral-like retrotransposons DNA-only transposons Nonretroviral retrotransposons Site-specific recombinases
DNA-only transposons
Which of the following spontaneous lesions in DNA occurs most frequently in a mammalian cell? Cytosine deamination Depyrimidination Depurination Guanine alkylation Guanine oxidation
Depurination
All of the "ultraconserved" elements found in the human genome have been shown to encode long noncoding RNAs. -True -False
False
Which of the following nucleotides is hydrolyzed in both transcription and in translation elongation? GTP UTP TTP CTP
GTP
In assembling a nucleosome, normally the __________ histone dimers first combine to form a tetramer, which then further combines with two__________) histone dimers to form the octamer. -H2A-H2B; H3-H4 -H1-H2; H3-H4 -H2A-H2B; H1-H3 -H1-H3; H2A-H2B -H3-H4; H2A-H2B
H3-H4; H2A-H2B
Which of the following repair pathways can accurately repair a double-strand break? Homologous recombination Nonhomologous end joining Direct chemical reversal Nucleotide excision repair Base excision repair
Homologous recombination & Nonhomologous end joining
Which of the following better describes a typical, actively translated mRNA in its journey from the nucleus to the cytosol? -Initially linear, the mRNA enters the cytosol (5' end first), and adopts a circular conformation. -Initially in a circular conformation, the mRNA linearizes, enters the cytosol (5' end first), and remains linear. -Initially linear, the mRNA enters the cytosol (3' end first), and adopts a circular conformation. -Initially in a circular conformation, the mRNA linearizes, enters the cytosol (3' end first), and remains linear. -Initially linear, the mRNA enters the cytosol (3' end first), and remains linear.
Initially linear, the mRNA enters the cytosol (5' end first), and adopts a circular conformation.
It is a model organism used to study various eukaryotic cell and developmental processes such as cell division and cell death. Its hermaphrodite adult is composed of exactly 959 somatic (non-germ) cells, the lineage of each of which has been worked out with great precision. It is approximately 1 mm long. Which of the following describes this organism? -Its genome codes for a few thousand genes. -It is a vertebrate. -It is a plant pathogen that destroys many crops. -It can fly. -It can be frozen indefinitely in a state of suspended animation.
It can be frozen indefinitely in a state of suspended animation.
Which of the following is true about the molecule shown in the following drawing? -Its gene transcript normally undergoes alternative splicing. -It is normally composed of about 20 monomers. -This molecule normally undergoes various covalent modifications. -Its gene is transcribed by RNA polymerase I. -There are about 50 genes in our genome encoding this type of molecule.
It is normally composed of about 20 monomers.
This protein folds into a doughnut shape that can encircle DNA. It can load on the DNA only when the DNA is broken in both strands, so that the DNA can thread through the hole in the protein. Which of the following proteins do you think matches this description? -Topoisomerase II, which can create or relax superhelical tension in DNA -MCM, the helicase critical for the initiation and elongation of replication -Ku, the protein that recognizes DNA ends and can initiate nonhomologous end joining -RecA/Rad51, which carries out strand invasion in homologous recombination -PCNA, the sliding clamp for DNA polymerases at the replication forks
Ku, the protein that recognizes DNA ends and can initiate nonhomologous end joining
Which of the following is NOT correct regarding homologous recombination and its regulation? -Low usage of homologous recombination by human cells can lead to cancer. -Excessive use of homologous recombination by human cells can lead to cancer. -Loss of heterozygosity can occur if a broken chromosome is repaired using a sister chromatid instead of its homologous chromosome. -Homologous recombination can rescue broken or stalled replication forks in S phase. -Repair of double-strand breaks by homologous recombination is favored during or soon after DNA replication.
Loss of heterozygosity can occur if a broken chromosome is repaired using a sister chromatid instead of its homologous chromosome.
The bond energies associated with noncovalent attractions in the cell are too weak to resist disruption by thermal motion. However, cellular macromolecules can interact specifically AND strongly with each other (or fold by themselves) merely via such interactions. How is this possible?
Many weak bonds together in a complementary geometry can afford a strong binding.
Which of the following would most reliably suggest that a genomic sequence is functionally important? -Multispecies conservation of the sequence -Low copy number variation of the sequence -The presence of active chromatin marks over the sequence -The presence of a long open reading frame in the sequence
Multispecies conservation of the sequence
In humans, nearly 80% of proteins are acetylated on their N-terminal residue, a modification known to be recognized by a specific E3 enzyme, which directs the ubiquitylation of the protein for rapid degradation. Does this mean that all of these proteins are actively degraded at any given time? -No; the E3 enzyme recognizing this mark is inactive most of the time. -No; the destruction signal can be buried in the interior of the protein or bound to other proteins. -Yes; this high turnover rate ensures that their activity is under tight control. -Yes; but they are not fully degraded in this way and can still function as protein fragments.
No; the destruction signal can be buried in the interior of the protein or bound to other proteins.
Which of the following groups of living organisms has the highest variation in haploid genome size? Prokaryotes Fish Mammals Protozoa Fungi
Protozoa
In which phases of the eukaryotic cell cycle does homologous recombination often occur to repair DNA damage? S and G2 phases G1 and S phases G1 and G2 phases M and G1 phases G2 and M phases
S and G2 phases
If this protein complex does not function normally, the ends of the eukaryotic chromosomes would activate the cell's DNA damage response, causing chromosomal fusions and other genomic anomalies. What is this protein complex called? ORC Shelterin T-loop Telomerase RecA
Shelterin
Imagine a chromosome translocation event that brings a gene encoding a histone acetyl transferase enzyme from its original chromosomal location to a new one near heterochromatin. Which of the following scenarios is definitely NOT going to happen? --The level of the gene product decreases due to a position effect, leading to an imbalance in the chromatin state of the cell that results in the activation of programmed cell death. --The translocation event also brings along a chromatin barrier that can prevent heterochromatin expansion into the gene, and there is no phenotypic anomaly. --The gene gets silenced due to heterochromatin expansion, leading to the misregulation of gene expression for a number of critical genes. --Since the gene encodes a histone acetyl transferase, it resists heterochromatin expansion by acetylating its own histones.
Since the gene encodes a histone acetyl transferase, it resists heterochromatin expansion by acetylating its own histones.
Indicate true (T) and false (F) descriptions below regarding the nucleotide excision repair pathway. Your answer would be a four-letter string composed of letters T and F only, e.g. FFFF. ( ) It involves recognition of distortions in the DNA double helix rather than specific base changes. ( ) It involves endonucleolytic cleavage and helicase-mediated strand removal. ( ) It involves cleavage by the AP endonuclease. ( ) It is coupled to the DNA transcription machinery of the cell. TTFT TTFF FFTT TFTF
TTFT
An elongating ribosome is bound to appropriate tRNAs in both the A and the P sites and is ready for peptidyl transfer. What happens next? -The amino end of the amino acid is released from the A-site tRNA and joined to the free carboxyl group of the polypeptide chain linked to the P-site tRNA. -The carboxyl end of the polypeptide chain is released from the P-site tRNA and joined to the free amino group of the amino acid linked to the A-site tRNA. -The amino end of the polypeptide chain is released from the P-site tRNA and joined to the free carboxyl group of the amino acid linked to the A-site tRNA. -The carboxyl end of the amino acid is released from the A-site tRNA and joined to the free amino group of the polypeptide chain linked to the P-site tRNA.
The carboxyl end of the polypeptide chain is released from the P-site tRNA and joined to the free amino group of the amino acid linked to the A-site tRNA.
The eukaryotic chromosomes are organized inside the nucleus with a huge compaction ratio of several-thousand-fold. What is responsible for such a tight packaging? -The nuclear envelope which encapsulates the chromosomes -The various chromatin proteins that wrap and fold the DNA -The nuclear matrix that provides a firm scaffold
The various chromatin proteins that wrap and fold the DNA
Which of the following features is common between the bacterial and eukaryotic ribosomes in translation initiation? -They both interact with various translation initiation factors. -They both use an initiator tRNA that carries formylmethionine. -They both bind to the 5 end of the mRNA and move forward to find the start codon. -They both recognize the start codon by interacting with the Shine-Dalgarno sequence.
They both interact with various translation initiation factors.
Which of the following is NOT correct regarding both Cas9 and EcoRI? -They are both greatly useful in manipulating DNA and studying gene expression and function. -They are both part of bacterial defense mechanisms against foreign DNA. -They are both endonucleases. -They both recognize their target sequences with the help of guide RNAs. -They both create double-strand breaks in DNA.
They both recognize their target sequences with the help of guide RNAs.
Which of the following best describes the mechanism by which chromatin-remodeling complexes "loosen" the DNA wrapped around the core histones? -They remove histone H1 from the linker DNA adjacent to the core histone octamer. -They chemically modify core histones to alter the affinity between the histone octamer and the DNA. -They use energy derived from ATP hydrolysis to change the relative position of the DNA and the core histone octamer. -They chemically modify the DNA, changing the affinity between the histone octamer and the DNA.
They use energy derived from ATP hydrolysis to change the relative position of the DNA and the core histone octamer.
Studying the expression of a transcription regulatory protein in two cell types, you have performed experiments showing that the mRNA encoding the protein is present at comparable levels in the cytosol of both cell types. However, based on the expression of its target genes, you suspect that the protein activity might be significantly different in the two cell types. Which of the following steps in expression of the gene encoding this protein is more likely to be differentially controlled in these cell types? transcription translation mRNA degradation mRNA transport
Translation
You have carried out a genetic screen in a species of fish, and have identified a new gene in this organism. You have cloned and sequenced the gene, but do not know anything about the biochemical function of the gene product. Which of the following is the most sensible next step in order to get clues about the function? -Using MS/MS to sequence the gene product without the need for purification -Purifying the protein product and determining its structure by x-ray diffraction -Screening for small molecules that perturb gene function -Mutating the gene and performing reverse genetics -Using the BLAST algorithm to scan sequence databases for similar sequences
Using the BLAST algorithm to scan sequence databases for similar sequences
Compared to the human genome, the yeast genome typically has
a higher fraction of coding DNA
The post-translational modification of phosphorylation always -activates a molecule -inhibits a molecule -adds a phosphate group to the substrate -adds a phosphate atom to the substrate
adds a phosphate group to the substrate
A DNA-binding protein binds cooperatively to DNA by fairly weak homodimerization. The binding of this protein to DNA ... -occurs in more of an all-or-none manner, compared to a protein that is a constitutive dimer. -occurs despite the fact that the protein molecules are -----predominantly monomers in solution. -shows a sigmoidal binding curve.
all above
A common theme among the paper is -data analysis can be hypothesis generating which means we go in with an exploratory approach to look at what changes were made globally within the cell -all cells have the DNA and ability to have heir gene expression changed because the DNA was present and accounted for even after differentiation -changing signaling pathway expression can have drastic effects on the livelyhood of the cell
all above
Although quite inefficient, cloning by nuclear transplantation can be successful, as exemplified by cloning of the famous Dolly. Such a success implies that ... -even a differentiated nucleus contains a complete genome, capable of supporting the development of an entire organism. -nuclei can be reprogrammed by cytoplasmic factors in a foreign cytoplasm. -epigenetic changes in somatic cells are not functionally irreversible.
all above
Enzymes allow for chemical reactions to occur in the cell that may not naturally occur at the right place at the right time. They are exceptionally useful as -their activity can be regulated by post-tranlational modifications -they can be localized within a cell to increase localized activity -their active site can be highly specific to distinguish between molecules
all above
How is tRNA splicing different from mRNA splicing in eukaryotic cells? -tRNA splicing does not proceed via transesterification reactions. -tRNA splicing does not create a lariat intermediate. -tRNA splicing involves RNA endonuclease and RNA ligase activities. -tRNA splicing is carried out by proteins only.
all above
How is the gene that is about to be turned on located within the nucleus? (consider a quick search on the purpose and function of a nuclear lamin) -within the center of the nucleus -due to binding of lamin and lamin receptors via the cytoskeleton -by the addition and removal of lipid to the lamin protein
all above
In the induced pluripotent stem cell paper, the authors needed to provide figure 1A -because you must report the types of inducing agents that were used so others can -because you must report the order of inducing agents that were used so others can replicate
all above
In the neurobalstoma paper, the authors attempt to visualize the effect of vasculature because -Blood vessels are recruited to the site of a tumor via cell signaling -the cancer has been associated with loss of vascular integrity
all above
In the neuroblastoma paper, figure 4A is important because -it demonstrates a difference in cell adhesion when they express the miRNA -there are a large number of cells still present although some could be migrating out of frame -it demonstrates the researchers can induce the expression of their miRNA
all above
In the primary research article the authors -were determining if the source of regeneration cells came from one localized area or throughout -use telomerase as a read-out of replicating cells -did not identify markers outside of telomerase that were specific to regenerating cells
all above
In the primary research article the authors utilized the LoxP system to -use telomerase transcription factors to initiate Cre expression -to initiate cre expression which then shifted mCherry into frame for transcription -to label cells that had transcription factors available for telomerase activity
all above
In the primary research article, what was the purpose of making the final figure with the micro CT-scan that was color coded? -to demonstrate how cool they looked -to demonstrate where the tissues finally landed after development -to demonstrate where the gene expression was tied in relation to the developing organs
all above
In the research paper, the author used BrdU -to visualize where dividing cells are -to allow for incorporation into the DNA during synthesis -because she worked with squid, and since not many people worked with squid there are not many antibodies for squids
all above
In the tet mutant zebrafish paper, the authors maintained most of their focus on the double mutants (tet 2 -/- and tet 3 -/-). They even stated that they did not see drastic phenotypes in single mutants, or 1 mutant and het for the other gene. What is a possible reason they made this observation? -when tet 3 is missing making more tet 2 can do the job -the tet proteins work in a regulation loop in order to ensure there is a proper level of ANY tet protein -when tet 2 is missing making more tet 3 can do the job -Since the enzymes are family members it is possible they can do similar functions
all above
In the tet paper, the researchers used the GO analysis because it would look for links between genes that they knew were expressed based on their RNA sequencing data to get an idea of what possible groups of genes had been affected in the mutant as a hypothesis generating method
all above
Nucleosomes that are positioned like beads on a string over a region of DNA can interact to form higher orders of chromatin structure. Which of the following factors can contribute to the formation of the 30-nm chromatin fiber from these nucleosomes? -Binding of proteins to DNA or the histones -Interactions that involve the histone tails of neighboring nucleosomes -Interaction of the linker histone H1 with each nucleosome -ATP-dependent function of chromatin remodeling complexes
all above
Polymerase Chain Reaction (PCR) amplification -originally started with scientists moving tubes from a hot water bath, to a cool water bath, to a medium water bath by hand every 30 seconds for 3 hours -requires that you know the DNA sequence in which you are attempting to amplify -can be used to amplify RNA sequences with some slight differences to the protocol -requires that dNTPs be added to the tube as the cell is not present to provide them
all above
Some of the side effects of using lipophillic dies for lineage tracing experiments is, --you do not need to make a transgenic but can look at a cell immediately --the lipophillic dye can spread to any neighboring cell or future daughter cell --the cell can leave a trail behind itself as it moves through an organism which can confound data
all above
The chromatin remodeling complexes play an important role in chromatin regulation in the nucleus. They ... -can remove or exchange core histone subunits. -have ATPase activity. -can slide nucleosomes on DNA. -interact with histone chaperones.
all above
To ensure the fidelity of splicing, the spliceosome... -examines the splicing signals on the pre-mRNA several times. -takes advantage of "exon definition." -hydrolyzes ATP to undergo complex rearrangements. -assembles on the pre-mRNA co-transcriptionally.
all above
Upon heavy damage to the cell's DNA, the normal replicative DNA polymerases may stall when encountering damaged DNA, triggering the use of backup translesion polymerases. These backup polymerases ... -lack 3-to-5 exonucleolytic proofreading activity. -are replaced by the replicative polymerases after adding only a few nucleotides. -can create mutations even on undamaged DNA. -may recognize specific DNA damage and add the appropriate nucleotide to restore the original sequence.
all above
What is the purpose of an RFLP sequence site? -It is a sequence that naturally occurs in DNA due to chance and is specific for bacterial nucleases -it is regularly used for a verification of method of gene knock out -Due to the palindromic nature it allows for DNA to have a guide for re-sealing the DNA to help avoid errors in recombining the DNA after a break
all above
When considering whether to use Zn finger cutters, TALEN or Cas 9, what is/are the caveat(s) that need to be considered? The efficiency of the method The efficacy of the method Whether it is effective in your model organism
all above
Which of the following is directed by transcription activators in eukaryotic cells in order to provide a more accessible DNA for the transcription machinery? Histone removal Nucleosome remodeling Histone replacement Histone modifications
all above
Which of the following is directed by transcription activators in eukaryotic cells in order to provide a more accessible DNA for the transcription machinery? Nucleosome remodeling Histone replacement Histone removal Histone modifications
all above
Which of the following processes takes place in the nucleoli within the eukaryotic nucleus? Telomerase assembly rRNA gene transcription tRNA processing Ribosome assembly
all above
You genetically removed the C-terminal coding region of your favorite protein/enzyme. When attempting to identify how your protein's function is affected by the loss of the C-terminal, you could -run a co-immunoprecipitation where you remove your favorite protein from suspension and all other proteins that are bound. Follow this step with running an SDS-PAGE gel and then visualizing the number of bands when compared to the wildtype version could demonstrate increased binding partners (additional bands) or decreased binding partners (less bands) -run an affinity collumn assuming you knew a ligand which can pull out your protein of choice and whatever proteins are bound to it. Follow this with eluting all bound proteins and run a mass spec to identify which protein are present and if they have changed with the C-terminus missing -discover the proper conditions to crystalize your protein and determine if the overall structure changes
all above
Which of the following DNA-binding motifs uses beta-sheets to recognize DNA bases? The helix-turn-helix motif The zinc finger motif The leucine zipper The helix-loop-helix motif
all above - This highlights how the structure needs to bind the outer backbone of the DNA and dimerize with another transcriptional regulator. In this case, a beta-sheet structure is not conducive to these functions.
In the induced pluripotent stem cell paper, the researchers observed calcium levels utilizing a fluorescent read-out. -This was done because calcium is required to create insulin -milk does the body good -none of these answers because potassium efflux is required for vessicle fusion with the plasma membrane -an increase of calcium could indicate the vesicles filled with insulin to fuse with the plasma membrane
an increase of calcium could indicate the vesicles filled with insulin to fuse with the plasma membrane
Lampbrush chromosomes .... -are transcriptionally inactive. -have thousands of duplicated DNA molecules arranged side by side. -are mitotic chromosomes with two sister chromatids attached together only at the centromere. -are thought to have a structure that is relevant to mammalian chromosomes in interphase.
are thought to have a structure that is relevant to mammalian chromosomes in interphase.
Horizontal gene transfer is namely observed in -bacteria -tomatoes -fish -mammals
bacteria
Western Blot analysis is limited -because you must have an antibody to every protein that exists in a cell -because if you used a whole cell lysate without -centrifugation you would know your protein is present but not where is lives inside the cell -There are no limitations to western blot analysis because it is hard to do
because if you used a whole cell lysate without -centrifugation you would know your protein is present but not where is lives inside the cell
Due to their high transcription rate, active ribosomal RNA (rRNA) genes can be easily distinguished in electron micrographs of chromatin spreads. They have a characteristic "Christmas tree" appearance, where the DNA template is the "trunk" of the tree and the nascent RNA transcripts form closely packed "branches." At the base of each branch is an RNA polymerase extending that branch, while RNA processing complexes at the tip of the branch form terminal "ornaments." The top of the tree represents the ... of the rRNA gene, and the "ornaments" are at the ... end of the nascent rRNA molecules. end; 3' end: 5' beginning; either 3' or 5' beginning; 3' beginning; 5'
beginning; 5'
The structural formulas for a few antibiotics that target the ribosome are shown below. Which one do you think is that of puromycin? Hint: puromycin mimics the structure of an amino acid linked to a tRNA molecule. C E B D A
c
The acetylation of lysines on the histone tails -can be performed on methylated lysines only after they are first demethylated. -is sufficient for the formation of an open chromatin structure. -is a covalent modification and is thus irreversible. recruits the heterochromatin protein HP1, resulting in the establishment of heterochromatin. -loosens the chromatin structure because it adds positive charges to the histone.
can be performed on methylated lysines only after they are first demethylated.
DNA-only transposons ... -often encode a transposase that mediates the transposition process. -leave double-strand breaks in the donor chromosome. -can move by a cut-and-paste mechanism. -can be recognized by the presence of short inverted repeats at each end.
can be recognized by the presence of short inverted repeats at each end.
snRNAs _________. are translated into snRNPs. are important for producing mature mRNA transcripts in bacteria. are removed by the spliceosome during RNA splicing. can bind to specific sequences at intron-exon boundaries through complementary base-pairing.
can bind to specific sequences at intron-exon boundaries through complementary base-pairing.
Polysomes... -are mostly translationally inactive and are normally used by the cell to store the ribosomes and their associated mRNAs for future use. -are large cytoplasmic assemblies made of several ribosomes each translating their exclusive mRNA. -are only found in the eukaryotic cytoplasm. -can take advantage of the circularization of eukaryotic mRNA (by interactions between the 5' and 3' ends of the mRNA) to further speed up the rate of protein synthesis.
can take advantage of the circularization of eukaryotic mRNA (by interactions between the 5' and 3' ends of the mRNA) to further speed up the rate of protein synthesis.
In the zebrafish genome methylation paper, the authors deteremined when hydroxymethylation marks are not allowed to be formed via the tet enzyme -neural genes became ectopically expressed -all genes expressed normally, the phenotype was solely due to over proliferation -all genes expressed normally, the phenotype was solely due to increased apoptosis -cardiac genes became ectopically expressed
cardiac genes became ectopically expressed
Eukaryotic pre-mRNAs undergo a number of modifications such as capping at the 5' end. A 5' cap... is identical for all mRNAs that are transcribed by RNA polymerase II. -contains a triphosphate bridge between the terminal base and the 5' end of the pre-mRNA. -has a 3'-to-5' linkage between the terminal nucleotide and the 5' end of the pre-mRNA. -carries a negative charge in the terminal base due to methylation. -consists of a modified terminal adenine nucleotide.
contains a triphosphate bridge between the terminal base and the 5' end of the pre-mRNA.
Which of the processes listed below is NOT thought to contribute significantly to the evolution of new genes? -mutation of existing genes to create new functions -formation of new gene de novo (from scratch) from noncoding DNA in the genome -horizontal transfer of DNA between cells of different species -duplication of genes to create extra copies that can aquire new functions -shuffling of domains of one gene by gene rearrangement
formation of new gene de novo (from scratch) from noncoding DNA in the genome
What is an organism' total genetic information which embodies its complete DNA sequence?
genome
The concept of a hertiable molecule (that we now know is DNA) between cells -began in the 80s when we could copy DNA -had long been theorized before it could be demonstrated -occurred in the 1920s occurred in the 1940s
had long been theorized before it could be demonstrated
The telomerase enzyme in human cells ... has an RNA component. -removes telomeric DNA from the ends of the chromosomes. -creates the "end-replication" problem. -extends the telomeres by its RNA polymerase activity. -polymerizes the telomeric DNA sequences without using any template.
has an RNA component.
Polytene chromosomes are useful for studying chromatin because they -have distinct visible banding patterns. -are smaller than regular chromosomes and easier to manipulate. -can make polyploid cells. -lack heterochromatin.
have distinct visible banding patterns.
The human genome project demonstrated - how little of our DNA we have a known function for -that our genome was never attacked by transponable elements of DNA -that our genome is roughly 1 million nucleotides long
how little of our DNA we have a known function for
The beauty of complimentary base pairing is.... (One answer is better than the other) -if you know one side you know the other exact nucleotide -you can narrow down the opposing sides sequence to one of the other three nucleotides -Either side can be used to make the exact same RNA despite which direction the gene is read in
if you know one side you know the other exact nucleotide
Total nucleic acids are extracted from a culture of yeast cells and are then mixed with resin beads to which the polynucleotide 5'-TTTTTTTTTTTTTTTTTTTTTTTTT-3' has been covalently attached. After a short incubation, the beads are then extracted from the mixture. When you analyze the cellular nucleic acids that have stuck to the beads, which of the following is most abundant? rRNA tRNA DNA mRNA
mRNA
It has been shown that inhibition of a key chromatin remodeling complex known as NuRD, by deleting one of its subunits, can result in a significant increase in the efficiency of reprogramming of somatic cells into pluripotent stem cells. The reprogramming is normally done by the induced expression of a battery of transcription factors in the somatic cells, but is typically not very efficient. Such an observation suggests that the NuRD complex is normally involved in ... -preventing DNA replication. -formation of extended loops from chromosome territories. -maintaining the epigenetic memory in somatic cells. -erasing the epigenetic memory in somatic cells.
maintaining the epigenetic memory in somatic cells.
Which proteins do you predict are bound to the promoter in experiment #8? only G and J only G and H only J only H and J
only G and J
The acetylation of lysines on the histone tails.... loosens the chromatin structure because it adds positive charges to the histone. -recruits the heterochromatin protein HP1, resulting in the establishment of heterochromatin. -can be performed on methylated lysines only after they are first demethylated. -is sufficient for the formation of an open chromatin structure. is a covalent modification and is thus irreversible.
recruits the heterochromatin protein HP1, resulting in the establishment of heterochromatin.
The two chromosomes in each of the 22 homologous pairs in our cells ... -show identical banding patterns after Giemsa staining. -have the exact same DNA sequence. -usually bear different sets of genes. -are derived from one of our parents.
show identical banding patterns after Giemsa staining.
Our understanding of RNA -was non-existent until 2000 -started with the identification of a tRNA which suggested a method of converting DNA to protein began to identify that DNA-->protein--> RNA -stopped growing after it's original discovery in the 70s
started with the identification of a tRNA which suggested a method of converting DNA to protein began to identify that DNA-->protein--> RNA
In the primary research article, the authors ruled out migration as a possible mechanism of how the increased number of red cells appeared by -checking before and after all of the different locations these cells could be migrating from -They made in vivo (live) imaging videos and watched that the cells did not move -both serial sections of livers before and after induction of tomato fate mapping AND live imaging -the authors did not test this but instead stated since no one has ever see this happen it is not the method
the authors did not test this but instead stated since no one has ever see this happen it is not the method
Molecular genetics focuses moreso on hydrophillic molecules because -membrane bound organelles are useless in the cell -the central dogma processes occur in the nucleus and cytosol -the central dogma processes occur in the nucleus -the central dogma processes occur in the cytosol
the central dogma processes occur in the nucleus and cytosol
In the neuroblastoma paper, the data from Figure 2A represents -the number of cells present after treatment -the life span of the mouse that was treated with the particular miRNA -The concentration of miRNA that the mouse was treated with at different times in its life -the changes in gene expression of the particular miRNA
the number of cells present after treatment
Consider a cis-regulatory enhancer sequence in the Escherichia coli chromosome that is located thousands of nucleotide pairs upstream of the gene that it regulates. If the regulatory sequence is mutated to become nonfunctional, the introduction of the wild-type enhancer on a plasmid fails to regulate the gene. This implies that ... -the regulatory sequence can bind directly to the RNA polymerase. -the regulatory sequence cannot bind to a protein. -the regulatory sequence encodes a regulatory protein that binds near the promoter of the target gene and controls RNA polymerase binding. -the regulation of the target gene involves looping out of --the intervening DNA, and the promoter of the cis-regulatory sequence must be on the same chromosome.
the regulation of the target gene involves looping out of --the intervening DNA, and the promoter of the cis-regulatory sequence must be on the same chromosome.
The distinct characteristics of different cell types in a multicellular organism result mainly from the differential regulation of the _________________. proteins that directly bind the TATA box of eukaryotic genes. replication of specific genes. transcription of housekeeping genes. transcription of genes transcribed by RNA polymerase II.
transcription of genes transcribed by RNA polymerase II.
The process of sorting human chromosome pairs by size and morphology is called karyotyping. A modern method employed for karyotyping is called chromosome painting. -How are individual chromosomes "painted"? -with a laser -using green fluorescent protein -using fluorescent antibodies -using fluorescent DNA molecules
using fluorescent DNA molecules
