Unit 3 Quizzes Bio 172

Enhancers are A) DNA sequences to which regulatory transcription factors bind B) Proteins located adjacent to promoters C) Proteins that bind to repressors to ensure that transcription does not occur D) Bacterial promoters

A

Which of the following would NOT be different between your brain cells and your skin cells? A) DNA sequences of enhancer elements B) The genes expressed in the two cells C) The pattern of chromatin packing in the nuclear DNA D) The methylation patterns of the DNA

A

A constitutively active gene is A) under negative transcriptional control. B) expressed continuously. C) does not need RNA polymerase for gene transcription. D) under positive transcriptional control.

B

Complete the following sentence: Acetylation of histones neutralizes the _____________ charges on histones, therefore phosphate groups on DNA are __________ attracted to them. A) negative, more B) positive, less C) negative, less D) positive, more

B

DNA wrapped around a group of histone proteins is called a A) nucleoid B) nucleosome C) supercoil D) scaffold

B

Histone acetyl transferases exert their effect on gene activity by A) Covalently binding to the DNA B) Neutralizing the positive charges of basic histones C) Attaching histones to the DNA D) Causing the DNA to condense

B

In DNA methylation in mammals, which nitrogenous base is most frequently methylated? A) adenine B) cytosine C) guanine D) thymine

B

Muscle cells and nerve cells in a single organism owe their differences to A) Having different chromosomes B) Expressing different genes C) Having different enhancer elements D) Using different genetic codes

B

Which mechanism of gene regulation is used only in eukaryotes and not in prokaryotes? A) Several genes acting in the same pathway are transcribed as one polycistronic RNA B) Regulation of chromatin structure by modifying histones C) A small molecule binding to a protein changes its conformation and activity D) DNA binding proteins bind to specific DNA sequences to regulate transcription

B

Which of the following is different between Pioneer regulatory transcription factors and non-pioneer regulatory transcription factors? A) One binds co-regulators and one binds the Mediator complex B) All options are correct (all are differences) C) One requires DNA looping while the other does not D) One requires a pre-existing open DNA conformation and the other does not

B

Which of the following is true of DNA methylation? A) DNA methylation blocks transcription by changing DNA nucleotide sequence B) DNA methylation is a chemical modification to the DNA which can influence gene expression C) Methyl groups when bound to the promoter, recruit RNA polymerase D) Heavy methylation of DNA activates transcription

B

Which one of the following statements about gene regulation is INCORRECT? A) Genes can be regulated at the level of transcription. B) Genes are regulated only in eukaryotes. C) Genes can be regulated at the level of chromatin structure. D) Genes can be regulated at the post-translational level. E) Genes can be regulated at the translational level.

B

Which statement about eukaryotic promoters is FALSE? A) A Promoter by itself is insufficient for transcription B) The eukaryotic RNA polymerase binds directly to Promoter DNA sequences C) The Basal Transcription Complex assembles at the Promoter D) General transcription factors bind to Promoter DNA sequences

B

A high throughput sequencing project yields the following sequence for a strand of DNA: 5'-GGTTTGGAGTAT-3'. Which of the following sequences overlap with the sequence above? ______________________________________________________________________________ A) None of the sequences overlaps with the sequence above. B) 5'-GGCTTGAGGTTA-3' C) 5'-GAGTATCCAAAT-3' D) 5'-GGTTTTTAGACT-3' E) 5'-GTGTTGGAGCTT-3'

C

A long string of codons for amino acids, uninterrupted by a stop codon is called A) a transposable element B) C-value paradox C) an open reading frame D) a tandem repeat

C

Positive transcriptional regulation means that A) transcription is definitely regulated in some way. B) transcription being turned on is a good thing for the cell. C) there is a regulatory factor that turns on transcription. D) there is a regulatory factor that turns off transcription.

C

Which of the following would a regulatory transcription factor most likely recruit to an enhancer? A) HDACs B) RNA polymerase C) HATs D) Basal transcription factors

C

Lactose is A) a transporter B) encoded by the gene LacZ C) a DNA-binding protein D) an energy source for a bacterial cell

D

Runner is a protein that can be used for cellular movement. The runner protein in white blood cells is 140 amino acids long while the runner protein in skin cells is 110 amino acids long. What can account for this difference? A) There are different transcription factors in white blood cells and skin cells. B) The transcripts for the runner gene are rapidly degraded in skin cells is transcribed differently. C) There is a miRNA that targets the runner mRNA in white blood cells but not skin cells. D)There is alternate splicing of the runner mRNA.

D

The gene E01G4.3 is regulated by a short RNA. You notice that when the short RNA is not present, mRNA levels levels of E01G4.3 increase. This short RNA is likely to be a A) snRNA B) tRNA C) mRNA D) miRNA

D

The human body contains approximately 200 major cell types. They look and function differently from one another because each: A) has a slightly different genome and each expresses a different set of genes. B) expresses the same set of genes, but in different orders at different times. C) has a slightly different genome. D) expresses a different set of genes.

D

What is the function of lactose permease? A) It transports lactose into the nucleus of the cell. B) It helps cleave lactose into glucose and galactose. C) It covalently modifies beta-galactosidase. D) It transports lactose into a cell.

D

Which of the following would a regulatory transcription factor most likely recruit to a silencer? A) Basal transcription factors B) HATs C) RNA polymerase D) HDACs

D

Using current DNA-sequencing technology, it is possible to sequence an entire chromosome (e.g., human chromosome 1, which contains approximately 250 million nucleotides) as one long molecule. False True

False

An operator is: A) a protein encoded by the structural genes of an operon B) is a different name for the repressor protein C) a region of DNA consisting of an operon, the promoter, and the coding sequences for the structural genes D) a regulatory region in DNA; the binding site for a transcription factor

Not A

Which best describes the process of high throughput sequencing? A) The use of firearms in sequencing DNA. B) Large scale sequencing of an organism's cDNA C) Automated sequencing of DNA D) Systematic sequencing of the genome, starting at one end of one chromosome and proceeding in order E) Sequencing many randomly created pieces of the genome, and then assembling the sequences into a finished product.

Not C, Probably E

(True or False) Positive regulation of transcription requires an activator protein to help RNA polymerase bind.

True

Replica plating was used to find mutant E. coli that cannot utilize lactose as a food source because A) It is better to have two copies of each experiment B) The E. coli colonies on the first plate became too old, and were unable to grow C) Bacteria with the desired mutation will not grow on lactose only plates D) Bacteria with the desired mutations will not grow on glucose only plates

c

Chromatin remodeling refers to the process by which: A) nucleosomes packing is altered to vary which stretches of DNA are accessible to DNA-binding proteins. B) DNA strands are "straightened out" to allow access to the proteins that carry out transcription. C) DNA strands are "unzipped" to allow access to the proteins that carry out transcription. D) methylation occurs in CpG islands. E) mutations change DNA structure and therefore chromatin structure.

A

Proteasomes A) help to regulate protein levels B) are proteins found in ribosomes. C) regulate ribosome function. D) package DNA around histones.

A

Proteins which bind to a gene's promoter to recruit factors necessary to recruit RNA Pol and start transcription are called A) general transcription factors B) enhancers C) introns D) regulatory transcription factors

A

The E. coli Trp operon is regulated by the Trp repressor. When Trp levels are high in the cell, Trp binds to the repressor and this allows the repressor to bind to the operator. What would be the result if the repressor was mutated in such a way that it could no longer bind Trp? A) Expression of the Trp operon genes in the operon would be high regardless of Trp levels in the cell B) Expression of the Trp operon genes in the operon would be low regardless of Trp levels in the cell C) Expression of the Trp operon genes in the operon would be high in the presence of Trp and low in the absence of Trp D) Expression of the Trp operon genes in the operon would be low in the presence of Trp and high in the absence of Trp in the cell

A

What characteristic of genes would classify them as belonging to the same operon? A) They are under the control of the same promoter and operator sequence. B) They would all require RNA polymerase to activate transcription. C) The genes are under the control of the same operator, but have their own promoters. D) They have the same coding sequence.

A

What components are necessary for a genetic screen? A) One would need a substance that induces mutations as well as a selection criteria for the mutants of interest. B) One only needs a substance that will induce mutations. C) One only needs a selection criteria for the mutants of interest. D) One only needs the proper types of replica plates.

A

What is a major role for the 3' UTR in mRNA? A) mRNA stability B) Aids in alternative splicing. C) Aids in enzymatic addition of poly A tail. D) Allows transcription initiation.

A

What is the major function of the mRNA 5' cap? A) Initiation of translation. B) Initiates mRNA processing. C) Transportation out of the nucleus. D) Control of mRNA degradation.

A

Which gene encodes the protein beta-galactosidase? A) lacZ B) lacI C) lacY D) lacA

A

Histone modification: A) can change over time in response to environmental cues, but this has no effect on gene expression. B) can change over time in response to environmental cues, allowing genes to be turned on or off as needed. C) is fixed, but this has no effect on whether genes are expressed. D) is random; sometimes the lysines are modified and sometimes they are not, but the state is independent of the environment or cell type. E) is fixed; once a histone is modified, it stays that way and the genes with which it is associated are turned on or off permanently

B

In eukaryotes, certain types of proteins are only made in certain types of cells. Which of the following does NOT contribute to this difference? A) Different cell types have different patterns of DNA methylation. B) Different cell types have different enhancers DNA sequences. C) Different cell types have different regulatory transcription factors.

B

Negative transcriptional regulation means that A)transcription is not regulated in any way. B)there is a regulatory factor that turns off transcription. C)certain genes are not likely to be useful. D)there is a regulatory factor that turns on transcription.

B

What sequence is present in cDNAs but not genomic DNA? A) Promoters B) PolyA tail C) Introns D) Exons

B

A transcription factor that binds to an enhancer might be expected to recruit which of the following factor or factors? A) A DNA methyltransferase or a histone acetyltransferase B) A DNA methyltransferase or a histone deacetylase C) Histone acetyltransferase D) DNA methyltransferase E) Histone deacetylase

C

The process whereby researchers identify the various types of sequences present within a genome is known as A) Sanger sequencing B) intron sequencing C) genome annotation D) shotgun sequencing

C

What is the purpose of DNA sequencing? A) Express foreign proteins in bacteria using plasmid vectors B) Separate DNA molecules from RNA molecules C) Determine the nucleotide sequence of DNA molecules D) Amplify a short piece of DNA using Taq polymarese

C

Whole genome sequencing is often approached by a shotgun sequencing technique in which large genomes are: A) randomly digested, short fragments are sequenced, and the overlapping sequences are assembled from smallest to largest. B) randomly digested, short fragments are sequenced, and the overlapping sequences are assembled in order. C) All of these choices are correct. D) digested in a few specific spots, large fragments are sequenced, and the overlapping sequences are assembled in order. E) randomly digested, short fragments are sequenced, and the overlapping sequences are assembled from largest to smallest.

D

Why does addition of a ddNTP terminate synthesis of the growing DNA chain? A) The 3' carbon in the ddNTP has a hydroxyl group B) The 5' carbon in the ddNTP lacks a hydroxyl group C )The 5' carbon in the ddNTP has a hydroxyl group D) There are not enough dNTPs available. E) The 3' carbon in the ddNTP lacks a hydroxyl group

E

Consider two E. coli mutants: Mutant 1 has mutation in LacI, such that the protein can no longer bind DNA. Mutant 2 has a mutation in the operator, such that LacI can no longer bind to it. What will be the phenotype of these mutants? (Assume there is no glucose present) A) Both mutants will express high levels of beta-galactosidase both in the presence and in the absence of lactose B) Neither mutant will express beta-galactosidase whether or not lactose is present C) Mutant 1 will express high levels beta-galactosidase both in the presence and in the absence of lactose; mutant 2 will not express beta-galactosidase whether or not lactose is present D) Mutant 1 will not express beta-galactosidase whether or not lactose is present; mutant 2 will express high levels beta-galactosidase both in the presence and in the absence of lactose

A

In positive regulation: A) A regulatory molecule binds to the protein in order to activate transcription of the mRNA corresponding to the bound protein B) A regulatory molecule (usually protein) binds to the DNA near the gene in order for transcription to take place C) A regulatory molecule (usually a protein) binds to the DNA near the gene in order for transcription to be prevented D) A regulatory molecule binds to the protein in order to prevent transcription of the mRNA corresponding to the bound protein

B

The basal transcription complex assembles at the _______________, while regulatory transcription factors bind to the __________________. A) enhancer, enhancer B) promoter, enhancer C) promoter, promoter D) enhancer, promoter

B

In general, when cytosine bases in CpG islands are methylated: A) translation is active and rapid. B) transcription is active and rapid. C) transcription is repressed. D) translation is repressed. E) transcription is active, but slow.

C

Positive and negative transcriptional regulation differ in that: A) positive regulation requires that a promoter be present; a promoter is not necessary in negative regulation. B) in positive regulation, the binding of a regulatory protein to the DNA is necessary for transcription to occur; in negative regulation, no such protein is necessary. C) in positive regulation, the binding of a regulatory protein to the DNA is necessary for transcription to occur; in negative regulation, such binding prevents transcription. D) in positive regulation, the absence of a regulatory protein promotes transcription; in negative regulation, the absence of a regulatory protein promotes transcription. E) None of the answer options is correct.

C

When present in small amounts in sequencing reactions, ddNTPs terminate the sequencing reactions at different positions in the growing DNA strands. ddNTPs stop a sequencing reaction because they A) permanently bind to the active site of DNA polymerase B) lack a 5' phosphate group C) lack a hydroxyl group at their 3' D) cause DNA polymerase to fall off the template strand

C

Which condition would create the highest expression of beta-galactosidase for an E. coli cell? A) The cell growing in the presence of acetate B) The cell growing in the presence of galactose C) The cell growing in the presence of lactose D) The cell growing in the presence of glucose

C

Which of the following changes may lead to a decrease in expression of a regulated gene? A) a decrease in DNA methylation at the gene B) an increase in histone acetylation in the chromatin of the gene C) chromatin remodeling to open up the promoter of the gene D) an increase in HDAC activity

D

Which of the following is likely to be the same between a liver cell and a skin cell in a multicellular organism? A) mRNA transcripts in the cytoplasm B) chromatin condensation patterns C) DNA methylation patterns D) general transcription factors E) regulatory transcription factors

D

Which one of the following statements MOST accurately describes methylation? A) Methyl groups are most often added to guanine-cytosine base pairs because they are held by three hydrogen bonds, and this decreases the probability of gene expression. B) Methyl groups are most often added to adenine-thymine base pairs because they are held by only two hydrogen bonds, and this increases the probability of gene expression. C) Methyl groups are added to most bases in the promoter region of a specific gene so that RNA polymerase and its associated proteins will bind more efficiently. D) Methyl groups are most often added to cytosines increasing the probability of gene expression. E) Methyl groups are most often added to cytosines decreasing the probability of gene expression.

E

A histone acetyltransferase might be recruited to a _____________, while a histone deacetylase might be recruited to a ______________. Operator, silencer Enhancer, silencer Enhancer, enhancer Silencer, operator Silencer, enhancer

Enhancer, Silencer

Which of the following modes of gene regulation is used in both prokaryotes and eukaryotes? A) Transcription factors binding to enhancers B) Regulatory proteins binding to specific DNA elements C) Organizing genes into operons D) Chromatin remodeling E) Modification of histones

Not A

A LINE is an example of A) a transposable element B) a simple sequence repeat C) an open reading frame D) a palindrome

Not B or C

The whole genome shotgun sequencing approach depends primarily on A) sequencing repeated sequences within the genome B) methodical sequencing of a few large cloned fragments of DNA C) rapidly sequencing thousands of small, randomly cloned fragments D) sequencing an entire chromosome while it is still intact

C

Transposable elements are: A) proteins that can move into the nucleus. B) DNA sequences that can insert themselves into RNA. C) DNA sequences that can insert themselves into new positions within the genome. D) proteins that can move outside of the nucleus. E) None of the other answer options is correct.

C

Fill in the blanks. Regulatory transcription factors bind to ________________, while general transcription factors bind to _________________. A) enhancers, enhancers B) promoters, enhancers C) promoters, promoters D) enhancers, promoters

D

In terms of gene expression, what is a repressor molecule? A) A molecule that inhibits enzymatic activity. B) A molecule that promotes translation. C) A molecule that recruits RNA polymerase. D) A molecule that does not allow transcription to occur.

D

Which of the following statements about enhancers is correct? A) They are located only in introns B) They contain a unique base sequence called the TATA box C) They bind to general transcription factors to recruit RNA polymerase to the promoter D) They are found in a variety of locations in the DNA and are functional in any orientation

D

What is a eukaryotic promoter? A) The site where RNA polymerase associates with the DNA B) DNA sequences that promote transcription in specific cell types. C) The DNA bound by regulatory transcription factors

Not B

Why is it necessary to clear out DNA methylation during the production of gametes? A) To prevent the methylation from creating mutations B) Because methylated DNA cannot be replicated C) DNA methylation is NOT cleared out during gamete production D) To allow for expression of the entire genome in the next generation

Not C

In E. coli, lactose binds with the lactose operon ... A) LacI repressor, preventing it from binding to the operator. This allows the lacZ and lacY genes to be transcribed. B) operator, preventing it from binding to the repressor. This allows the lacZ and lacY genes to be transcribed. C) LacI repressor, helping it bind to the operator. This prevents the lacZ and lacY genes from being transcribed. D) operator, preventing RNA polymerase from being recruited. This prevents the lacZ and lacY genes from being transcribed. E) operator, recruiting RNA polymerase. This allows the lacZ and lacY genes to be transcribed.

Not D, Not C

GLD-1 is an RNA binding protein which binds to the 3' UTR of the MES-3 mRNA. If GLD-1 is not functional, MES-3 mRNA levels do not change, but MES-3 protein levels increase. The size of the MES-3 protein does not change, only its quantity. What is the function of GLD-1? A) inhibits translation B) enhances mRNA degradation C) promotes mRNA stability D) promotes alternative splicing E) promotes translation

Not E

Which of the following components of gene regulatory mechanisms is NOT used in eukaryotes. A) polycistronic operons B) DNA methylation C) histone methylation D) alternative splicing E) regulatory proteins binding to DNA sequences

A

Which of the following genes might not be constitutively expressed? A) The gene encoding stress hormone. B) The gene encoding the enzyme needed for the first step of glycolysis. C) The gene encoding the repressor protein (lacI). D) The gene encoding RNA polymerase.

A

Energy is required in order to add a nucleotide to the growing strands of DNA during DNA sequencing. Where does that energy come from? A) DNA polymerase B) DNA ligase C) DNA helicase D) Primer E) the incoming dNTP

E

Which of the following elements of the prokaryotic lac operon model could be considered analogous to a eukaryotic silencer? A) LacI gene B) LacI protein (Lac repressor) C) glucose D) CRP binding site E) Lac operator

E

DNA methylation patterns can be inherited from cell generation to the next because... A) An enzyme called DNA methyltransferase recognizes hemimethylated DNA and methylates the other strand B) All cytosines are methylated in eukaryotic DNA C) During the production of gametes DNA methylation is erased D) DNA polymerase can copy methylated DNA to produce another methylated copy

A

In an E.coli mutant beta-galactosidase is not expressed whether or not lactose is present. Which of the following can explain this phenotype? A) A mutation in the LacI protein which prevents binding to lactose B) A mutation in the LacI proteins which prevents binding to DNA C) A mutation in the operator which prevents LacI binding to it.

A

In negative regulation: A) A regulatory molecule (usually a protein) binds to the DNA near the gene in order to prevent transcription B) A regulatory molecule (usually a protein) binds to the DNA near the gene in order to for transcription to take place C) A regulatory DNA binds to an RNA molecule in order for transcription to take place D) A regulatory DNA binds to an RNA molecule in order to prevent transcription

A

You wish to identify a bacterial mutant that cannot utilize galactose as a sugar source. How would you perform the replica plating? A) First plate the bacteria on glucose, then replica plate onto a galactose only plate. B) First plate the bacteria on galactose, then replica plate onto a glucose only plate. C) First plate the bacteria on glucose, then replica plate on a lactose only plate. D) First plate the bacteria on a galactose plate, then replica plate on a glucose only then a lactose only plate.

A

What is the function of the enzyme beta-galactosidase? A) It regulates transcription of the lacY gene. B) It transports galactosidase into a cell. C) It cleaves lactose into glucose and galactose. D) It regulates transcription of the lacZ gene.

C

When looking for a possible eukaryotic open reading frame in a double stranded DNA molecule, how many frames must you check? A) 8 B) 2 C) 6 D) 4

C

Which of the following is NOT a DNA binding protein? A) CRP B) regulatory transcription factors C) HDACs D) the repressor LacI

C

Which of the following statements about DNA methylation is false? A) DNA methylation patterns can be copied following DNA replication. B) DNA methylation is associated with condensed chromatin. C) DNA methyltransferases add methyl groups to histones. D) Most DNA methylations are reset during gametogenesis.

C

Sequences of genomic DNA, and its corresponding messenger RNA (mRNA), are often compared to obtain valuable information for genome annotation. Why is this comparison useful? A) The genomic DNA is longer because the exons are spliced together. B) The sequences of genomic DNA and mRNA are identical, which serves as independent validation. C) The genomic DNA is shorter because the exons are spliced together. D) The open reading frame of the mRNA includes the introns of the genomic DNA. E) The exclusion of introns in mRNA reveals the intron-exon structure of many protein coding genes.

E

What is one reason that makes the identification of open reading frames harder in eukaryotes than it is in prokaryotes? A) In prokaryotes, only one strand of the DNA needs to be checked for the presence of open reading frames, while in eukaryotes, both strands need to be checked. B) The presence of operons in prokaryotes C) ATG is the start codon in prokaryotes, but not in eukaryotes D) Prokaryotes have more genes than eukaryotes E) The presence of introns in eukaryotes

E

Which one of the following can lead to changes in chromatin structure and is often associated with activation of transcription? A) methylation of RNA polymerase B) the presence of cytosine and guanine in a repeating sequence in the histone tail C) addition of lysine to cytosines along the histone tail D) methylation or acetylation of the phosphodiester link between cytosine and guanine E) addition of acetyl groups to lysines located in the histone tail

E

Which statement describes the proper order of steps leading to regulation by miRNAs? A) Synthesis of hairpin miRNA precursor, cleavage of miRNA, formation of the RISC complex, inhibition of translation. B) Synthesis of hairpin miRNA precursor, formation of the RISC complex, inhibition of translation, cleavage of miRNA. C) Synthesis of hairpin miRNA precursor, formation of the RISC complex, cleavage of miRNA, inhibition of translation. D) Formation of the RISC complex, Synthesis of hairpin miRNA precursor, cleavage of miRNA, inhibition of translation.

A

Whole genome sequencing is often approached by a high throughput sequencing technique in which large genomes are: A) randomly digested, short fragments are sequenced, and the overlapping sequences are assembled in order. B) randomly digested, short fragments are sequenced, and the overlapping sequences are assembled from smallest to largest. C) randomly digested, short fragments are sequenced, and the overlapping sequences are assembled from largest to smallest. D) digested in a few specific spots, large fragments are sequenced, and the overlapping sequences are assembled in order. E) All of these choices are correct.

A

Which one of the following statements about an open reading frame is TRUE? A) A long open reading frame may be protein coding. B) An open reading frame is uninterrupted by a stop codon. C) All of these choices are correct. D) An open reading frame consists of a long string of codons for amino acids.

C

An operon is a: A) gene coding for a repressor protein. B) region of DNA consisting of the promoter and operator sequences needed to regulate one or more structural genes. C) region of DNA consisting of the operator and coding sequences for structural proteins. D) region of DNA consisting of the promoter, the operator, and coding sequences for structural proteins. E) single molecule of RNA coding for more than one protein.

D

How do miRNAs regulate a specific mRNA? A) Through alternate splicing. B) By inhibiting the spliceosome C) By enhancing RNA editing. D) Through complementary base pairing with the mRNA.

D

Insulin is needed to regulate sugar levels in the blood. While every cell in the body contains genes for the production of insulin, it is only produced by a specialized subset of cells in the pancreas. Therefore: A) the genes for insulin production must be mutated except in the specialized cells of the pancreas. B) only the specialized cells of the pancreas have functional genes for insulin production. C) insulin production is not regulated because the genes for it are present in every cell. D) every cell must regulate its own sugar production. E) there must be mechanisms of gene regulation that promote insulin expression in the specialized pancreatic cells and prevent insulin expression in all other cells.

E

What modification takes place when lactose is present in a bacterial cell? A) Lactose induces a conformational change in the repressor protein. B) Lactose causes degradation of the repressor protein. C) Lactose promotes the association between cAMP and CRP. D) Lactose allosterically regulates the enzyme that produces cAMP.

A

What is a nucleosome? A) The site of transcription B) A component of DNA, made up of a ribose sugar, a base and a phosphate group C) DNA wrapped around a group of histone proteins D) An organelle found in eukaryotic cells, containing all chromosomes of the cell.

C

Which of the following has an inhibitory effect on transcription? A) Acetylation of histones B) Moving nucleosomes around to open up the promoter region of DNA C) Methylation of cytosines in DNA

C

Why does DNA fingerprinting assay 13 different VNTRs? A) to account for errors in the VNTR analysis process B) Some VNTRs are hard to amplify C) because individuals can share some VNTR alleles, but the likelihood of sharing all alelles at 13 VNTRs is 1 in 500 trillion

D

Gene Htz1 is expressed at high level in yeast cells. While studying regulation of Htz1 gene expression you find a protein, Wzt1, which binds to the Htz1 mRNA in the cytoplasm. Which of the following might Wzt1 do to regulate Htz1 expression? A) transport the Htz1 protein to the proteasome for degradation B) mediate the formation of a loop between the enhancer and the promoter C) posttranslationally modify the Htz1 protein D) recruit chromatin remodeling enzymes to the Htz1 gene E) regulate translation of Htz1

Not E or B

One difference between Sanger DNA sequencing and PCR is: A) Sanger DNA sequencing uses dideoxy nucleotides, while PCR does not B) Primer(s) is/are needed for PCR, but not for Sanger DNA sequencing C) Primer(s) is/are needed for Sanger DNA sequencing, but not for PCR D) PCR uses dideoxy nucleotides, while Sanger DNA sequencing does not

A

Packaging of DNA into chromatin... A) inhibits transcription by blocking Transcription Factor binding to their target DNA B) has no effect on transcription C) is identical in different cells of the body D) promotes transcription by opening up chromatin

A

In eukaryotic cells, why are certain genes expressed only in certain types of cells? A) Different cell types have the same genes but different enhancers B) Different cell types have different genes C) Different cell types have the same genes but different promoters D) Different cell types have different active regulatory transcription factors

D

Which mechanism of gene regulation is used only in prokaryotes and not in eukaryotes? A) A small molecule binding to a protein changes its conformation and activity B) Regulation of chromatin structure by modifying histones C) DNA binding proteins bind to specific DNA sequences to regulate transcription D) Several genes acting in the same pathway are transcribed as one polycistronic RNA

D

Choose the one correct statement from the choices below. A) Histone acetylation represses translation. B) Histone acetylation activates translation. C) Histone acetylation correlates with repression of transcription. D) Histone acetylation is random and has no effect on gene expression. E) Histone acetylation correlates with active transcription

E

Sequence assembly is accomplished by aligning the fragments: A) on paper. B) None of the other answer options is correct. C) in the laboratory by running them through gel electrophoresis. D) by joining histones. E) by using a complex computer program.

E