Chapter 12

At which time period(s) during PCR thermocycling is/are hottest in temperature? A) during DNA denaturation B) during primer annealing C) during primer extension/elongation D) Both the first and last cycles are hotter in temperature than all other cycles.

A

Expression vectors are designed to ensure that ________ can be efficiently ________. A) mRNA / transcribed B) DNA / transcribed C) mRNA / translated D) DNA / translated

A

If a foreign gene is cloned into an expression host, it is important that the host itself A) not produce the protein being studied. B) produce the protein in larger amounts than the vector. C) repress the genetic expression being studied. D) produce signal proteins to tag the host protein.

A

Inserting a kanamycin resistance cassette into a catabolic operon to confirm the gene is essential in degradation of a particular compound would involve all of the following EXCEPT A) a reporter gene. B) ligation. C) recombination. D) transformation.

A

It is possible to rapidly screen for mutations in regulatory genes using A) gene fusions. B) defective proteases. C) microinjection. D) Southern blotting.

A

One of the more formidable obstacles to mammalian gene cloning is the presence of A) introns. B) exons. C) repressors. D) integrators.

A

The enzyme that covalently links both strands of a vector and inserted DNA in molecular cloning is A) DNA ligase. B) DNA phosphatase. C) DNA hydrolase. D) DNA transferase.

A

The principle behind nucleic acid probe design is that the probe itself must contain A) a key complementary part of the target gene sequence of interest. B) all of the nucleotide sequence of the gene of interest to conclusively identify the gene. C) an antibody to specifically bind to the gene of interest. D) at least three separate complementary regions of the gene of interest.

A

To verify a gene was cloned into a vector successfully, sequencing the vector as well as ________ are commonly performed. A) agarose gel electrophoresis B) fluorescence in situ hybridization C) protein purification D) northern blots

A

What molecular mechanism/feature does site-directed mutagenesis exploit to introduce a mutation at a specific site? A) flanking complementary bound nucleotides permit non-complementary base pairing B) methylated nucleotides disrupt DNA polymeraseʹs proofreading C) nucleotide substitution when one is depleted D) transposase-induced base pair changes

A

Which objective would be best to use a Southern blot rather than a Northern blot? A) Determine if a gene is present in a genome. B) Discover gene function. C) Identify regulatory gene-protein interactions. D) Quantify expression profiles of a gene.

A

Which of the following terms is used to describe a synthetic DNA fragment? A) DNA cassette B) DNA hybrid C) recombinant DNA D) artificial chromosome

A

Which of those below is NOT an important consideration when designing a fusion protein construct? A) Avoid hybridization of the fusion gene in the artificial construct. B) Reading frame is the same for both the fusion gene and reporter gene. C) Transcriptional start and stop signals are shared. D) Translational start and stop signals are shared.

A

Which of those listed below is LEAST similar in what is being studied and concluded? A) fluorescence in situ hybridization B) GFP fusion protein C) Northern blot D) RT-PCR

A

Which statement is TRUE? A) YACs are more likely than BACs to undergo recombination and rearrangement. B) BACs are more likely than YACs to undergo recombination and rearrangement. C) YACs and BACs undergo recombination and rearrangement at about the same rate. D) It is impossible to state with any certainty whether YACs or BACs are more likely to undergo recombination and rearrangement, because environmental factors play a major role in the probability of one or the other occurring.

A

Cells that have "insertional inactivation" of the lacZ gene are A) blue. B) white. C) yellow. D) fluorescent green.

B

Cosmids are a type of A) bacterial artificial chromosomes (BACs). B) cloning vector. C) heat stable polymerase. D) RNA/DNA hybrid.

B

If a protein that could be toxic to the expression host needs to be expressed in large quantities, then it is best to select an expression vector that A) is not able to be replicated. B) is inducible. C) is attached to a normal cell promoter. D) allows continual expression of the protein.

B

The principle underlying how salmon were genetically engineered to grow faster is the A) removal of a gene responsible for feeling full after eating. B) replacement of inducible to constitutive hormone production. C) resistance to bacterial infections which waste metabolic energy in the salmon to fight off. D) addition of genes to enhance blood circulation and tissue development.

B

To estimate the total concentration of a beneficial bacterial species in yogurt, ________ would provide the quickest results. A) fluorescence in situ hybridization B) qPCR C) RT-PCR D) a Southern blot

B

Which of the following is NOT a common step in molecular cloning using plasmids? A) Fragment DNA into small segments. B) Hybridize DNA sequences with slightly mismatched oligonucleotides. C) Ligate DNA into vectors. D) Insert the vectors into a host.

B

A(n) ________ gene is a gene that encodes a protein that is easy to detect and assay. A) encoder B) translational C) reporter D) recorder

C

Some proteins expressed at high levels form inclusions that are relatively insoluble. What is the most effective way to facilitate purification of these proteins? A) Use a reporter gene to locate the inclusion. B) Decrease the number of insertions in the vector. C) Produce the protein as a fusion protein. D) Switch to an expression host with a larger intracellular volume.

C

The Ti plasmid is best suited for genetically manipulating A) Agrobacterium spp. B) fish. C) plants. D) viruses.

C

Using a host defective in proteases is likely to be necessary when A) engineering a complete metabolic pathway requiring several different enzymes. B) overproducing proteins. C) producing a small protein. D) engineering transgenic animals with immune systems.

C

What is the difference between PCR and RT-PCR? A) Only PCR makes many copies of DNA rapidly. B) RT-PCR uses an RNA template whereas PCR uses a DNA template. C) Only PCR produces cDNA. D) PCR uses a single stranded template whereas RT-PCR uses a double-stranded template.

C

What makes eukaryotic transcripts easier to isolate than bacterial transcripts? A) Eukaryotic transcripts are not methylated but their genes are often methylated. B) Larger transcript size in eukaryotes enables easy size-selection methods. C) mRNA is polyadenylated in eukaryotes. D) Transcripts are the most abundant RNAs in eukaryotes.

C

Which process results in the production of a hybrid polypeptide? A) vector fusion B) operon fusion C) protein fusion D) translational fusion

C

A polymerase chain reaction (PCR) copies an individual gene segment in vitro with a(n) ________ primer(s). A) individual RNA B) individual DNA C) pair of RNA D) pair of DNA

D

After digesting a DNA sequence, a restriction endonuclease can generate A) blunt ends. B) overhangs. C) sticky ends. D) blunt ends, overhangs, or sticky ends.

D

Cloning vectors can be distinguished from expression vectors by A) carrying ori genes for replication of the cloned sequence. B) having a multiple cloning site (MCS). C) having a high copy number per cell. D) lacking a promoter site upstream of the insertion site.

D

One challenge in cloning human somatotropin is that A) it consists of multiple polypeptides, making synthesis complex. B) its gene cannot be cloned as cDNA. C) it can only be expressed by eukaryotic cells. D) it is susceptible to digestion by bacterial proteases because it is a small protein hormone.

D

The genes encoding green fluorescent protein (GFP) and β-galactosidase are typically used in cloning as A) transcription regulators. B) global control genes. C) promoter sequences. D) reporter genes.

D

What is the most important advantage of Pfu polymerase over Taq polymerase? A) Unlike Taq polymerase, Pfu polymerase functions well at relatively high temperatures. B) It is from a bacterium, not an archaean, so it is more effective for replicating eukaryotic DNA. C) Pfu polymerase removes the need for primers during PCR. D) Unlike Taq polymerase, Pfu polymerase has proofreading activity.

D

Which of the following sequences is a palindrome, characteristic of many recognition sequences for restriction endonucleases? A) TTGCCGA AACGGCT B) GGGGGGG CCCCCCCC C) GTAATG CATTAC D) GAATTC CTTAAG

D

Genetically modified plants resistant to the herbicide glyphosphate contain a gene from Bacillus thuringiensis.

F

Green fluorescent protein (GFP) is used for detecting translational activity of a fused protein, whereas lacZ reporters are used to detect transcriptional activity of a fused gene.

F

High expression levels of a eukaryotic gene in a bacterium such as Escherichia coli cannot be accomplished due to the presence of introns.

F

One problem with both BACs and YACs is that genetic regions of these chromosomes cannot be subcloned.

F

PCR rapidly produces many copies of entire DNA molecules.

F

The lacZ gene is commonly used as a reporter gene, because its substrate lactose is well known and easily measured.

F

A common reporter protein is green fluorescent protein (GFP).

T

Although various codons often code for the same amino acid, it is important to choose the codon preferred by the expression host itself.

T

An effective way to introduce DNA into plant cells is using the Ti plasmid, which comes from a plant pathogen.

T

An operon fusion has a transcriptional signal from one gene fused with the translational start and coding sequence from another.

T

DNA ligase mediates the insertion of foreign DNA into a vector, but it will only be able to do so if the inserts and vector have matching sticky or blunt ends.

T

DNA polymerases from Escherichia coli cannot be used to artificially copy gene sequences with a thermocycler.

T

Modification enzymes typically methylate specific bases within the recognition sequence to prevent digestion of the nucleotide sequence by restriction endonucleases.

T

One fundamental technique of genetic engineering includes the ability to cut DNA into random fragments.

T

One important advantage of eukaryotic cells as hosts for cloning vectors is that they already possess the complex RNA and posttranslational processing systems required for the production of eukaryotic proteins.

T

One method to circumvent issues with introns when expressing a eukaryotic gene in a bacterium is to simply clone the mature transcript.

T

Regardless of the DNA polymerase used in PCR, such as Taq or Pfu, they all have an inherent inability to perfectly copy the template strand, which means the polymerases themselves occasionally make mutations in the sequences they copy.

T

Strong promoters used for genetic manipulation are usually regulated by specific molecules.

T

The key steps in cloning a foreign gene into a vector, regardless of the application, involve isolating the insert fragment, ligating the insert into a vector, and transforming it into a host.

T