MicroBio Chapter 11 Genetic Engineering and Biotechnology
18) 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
22) 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
29) 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
Electrophoresis can be used to separate molecules by size, shape, and charge. When DNA samples are run in an electrophoresis gel, the different bands produced generally represent fragments of different sizes. Why is the size of the fragment the most critical factor in determining how far it migrates on a gel when DNA fragments are compared? A DNA moves toward a positive charge due to the negative charge on its phosphate groups. The charge is consistent because all DNA nucleotides have a single phosphate group rather than having more diverse patterns of charges. Because the charge is relatively consistent, size is the most important factor determining how far fragments move. B The charge on DNA is so small that it has a minimal effect on movement in the gel. C The shape of the DNA fragments has an even greater effect on movement than size or charge, so charge is relatively unimportant. D A special type of gel is used for DNA electrophoresis to minimize the effects of charge.
A
13) Which of the following sequences would be cleaved by a type II restriction endonuclease? A) TTGCCGA AACGGCT B) GGGGGGG CCCCCCCC C) GTAATG CATTAC D) GAATTC CTTAAG
A inverted repeat sequence D) GAATTC CTTAAG
26) The enzyme that covalently links both strands of a vector and inserted DNA in molecular cloning is
A) DNA ligase.
11) 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.
19) Which statement is TRUE?
A) YACs are more likely than BACs to undergo recombination and rearrangement.
21) The principle behind a nucleic acid probe design is that the probe itself must contain
A) a key complementary part of the target gene sequence of interest.
10) To verify a gene was cloned into a vector successfully, sequencing the vector as well as ________ are commonly performed.
A) agarose gel electrophoresis
14) At which time period(s) during PCR thermocycling is/are hottest in temperature?
A) during DNA denaturation
17) 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 polymerase's proofreading C) nucleotide substitution when one is depleted D) transposase-induced base pair changes
A) flanking complementary bound nucleotides permit non-complementary base pairing
20) Which of those listed below is LEAST similar in what is measured and concluded? A) fluorescence in situ hybridization B) GFP fusion protein C) Northern blot D) RT-PCR
A) fluorescence in situ hybridization
6) One of the more formidable obstacles to mammalian gene cloning is the presence of
A) introns.
4) Expression vectors are designed to ensure that ________ can be efficiently ________.
A) mRNA / transcribed
1) If a foreign gene is cloned into an expression host, it is important that the host itself
A) not produce the protein being studied.
16) Which of the following is NOT a common step in creating a genomic library? A) Fragment DNA into small segments. B) Hybridize DNA sequences to form inserts of a target size range. C) Ligate DNA into vectors. D) Transform the vectors into a host.
B) Hybridize DNA sequences to form inserts of a target size range.
3) To discover a catabolic gene cluster, cloning large sequences of approximately 40 kbp requires the utility of
B) cosmids or fosmids.
31) If a protein to be overexpressed is toxic to the expression host, it is best to select an expression vector that A) is compatible with a binary vector able to be regulated. B) is inducible. C) has a relatively low copy number per cell. D) prevents folding of the overexpressed protein into its toxic form.
B) is inducible.
34) Polyvalent vaccines using vaccinia virus are highly favored by doctors and physicians but are especially challenging for those who develop them, because A) coat proteins form a relatively rigid structure and do not allow much space for additional proteins to be expressed. B) multiple foreign proteins simultaneously synthesized often disrupts each other's activity. C) vaccinia and most other viruses engineered for vaccines contain only one restriction site for cloning in their genome. D) virus genetic manipulation uses transfection, which is an inherently inefficient process.
B) multiple foreign proteins simultaneously synthesized often disrupts each other's activity.
33) The principle underlying how salmon were genetically engineered to grow faster is the
B) replacement of inducible to constitutive hormone production.
2) Detecting a specific protein with an antibody is considered a(n) ________ method.
B) screening
Restriction endonucleases are found in nature. They are extremely useful for genetic engineering. Why do organisms produce them?
Because they cut only at specific sequences in DNA, they are useful in cutting harmful DNA (such as viral DNA) without harming the organism that produces them (which can protect those sequences in its own DNA).
39) Using a host defective in proteases is likely to be necessary when engineering A) a complete metabolic pathway requiring several different enzymes. B) overproducing proteins. C) production of a small protein. D) transgenic animals with immune systems.
C
32) Some proteins overexpressed at high levels resulting in the formation of inclusion bodies can abolish the goal of producing large quantities of active protein. What could be done to minimize this issue? A) Codon optimize the gene. B) Decrease the number of biobricks in the vector. C) Simultaneously produce intracellular chaperonins. D) Switch to an expression host with a larger intracellular volume.
C) Simultaneously produce intracellular chaperonins.
37) Which of the following is NOT an example of synthetic biology? A) assembling gene sequences together into genome and creating a living organism from it B) creating a new metabolic pathway that produces a previously unidentified compound C) developing a novel polyvalent vaccine D) making Escherichia coli phototrophic
C) developing a novel polyvalent vaccine Synthetic biology - using genetic engineering to create novel biological systems out of available parts (biobricks) • Examples • Self-replicating synthetic bacterium • Genetically modified E. coli that produces photographs )
25) What makes eukaryotic transcripts easier to isolate than transcripts in bacteria? 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) mRNA is polyadenylated in eukaryotes.
28) The Ti plasmid is best suited for genetically manipulating
C) plants.
30) Which construct would be MOST useful in studying translational control? A) gene fusion B) operon fusion C) protein fusion D) shuttle vector
C) protein fusion
27) Type II restriction endonucleases A) are heterodimers. B) natively function to methylate specific nucleotides and prevent foreign DNA from being incorporated into the genome. C) recognize nucleotide sequences that are palindromic. D) require ATP energy to cleave dsDNA.
C) recognize nucleotide sequences that are palindromic.
5) A(n) ________ gene is a gene that encodes a protein that is easy to detect and assay.
C) reporter
8) What type of vector can replicate and be maintained stably in two (or more) unrelated host organisms?
C) shuttle
35) Recognizing pathogens that contain multiple unique proteins which enable the human immune system to recognize just one and mount an effective response has opened the door on development of some vaccines only being A) attenuated carrier viruses. B) monovalent. C) subunit vaccines. D) purified protein administered.
C) subunit vaccines.
23) A shuttle vector is most useful for A) engineering a complete metabolic pathway. B) identifying the localization of a protein. C) knocking out a gene by cassette displacement. D) making a foreign protein in a mammalian cell.
D
7) Which of the following is NOT a characteristic of a type II restriction endonuclease? A) cleavage product can be either blunt or sticky ended but is always the same for an individual enzyme B) recognizes a specific palindromic site for cleavage C) recognition site length varies among enzymes but is always the same for an individual enzyme D) unable to cleave methylated DNA
D
When a DNA gel is run, a standard sample with fragments of known size is often run in one well. Why is it important to use a standard sample? A The standard sample is used to demonstrate that the apparatus is working properly; it is a control. b The standard sample is used to make sure that the electrical current is working properly. C The standard sample helps to make the other samples more visible. D When an electrophoresis gel is run, small differences in the environment (e.g., the gel composition and current) can influence how far the fragments travel. Having a standard sample allows one to compare the test fragments with fragments of known size that have been run under the same conditions.
D
24) After digesting a DNA sequence, a restriction endonuclease can generate
D) blunt ends, overhangs, or sticky ends.
36) A poorly immunogenic vaccine often suggests the foreign proteins were not properly recognized by the immune system due to a lack of ________ necessary, which can also be engineered to occur with additional molecular manipulations. A) complex folding B) methylation C) glucosylation D) glycosylation
D) glycosylation
38) 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) lacking a promoter site upstream of the insertion site.
12) A polymerase chain reaction (PCR) copies an individual gene segment in vitro with a(n) ________ primer(s).
D) pair of DNA
9) The genes encoding luciferase, green fluorescent protein (GFP), and β-galactosidase are typically used in cloning as
D) reporter genes.
12) Engineering a metabolic pathway enables a researcher to use different genes from unrelated organisms.
F
18) Genomic libraries enable the discovery of individual gene(s) involved in a particular function of interest with cloning vectors in an expression host, such as Escherichia coli.
F
2) High expression levels of a eukaryotic gene in a bacterium such as Escherichia coli cannot be accomplished due to the presence of introns.
F
20) 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
7) The lacZ gene is commonly used as a reporter gene, because its substrate lactose is well known and easily measured.
F
8) One problem with both BACs and YACs is that genetic regions of these chromosomes cannot be subcloned.
F
If an electrophoresis gel is run with RNA and then a DNA probe is used to identify the fragments of interest, what is the process called? A Southern blotting B Northern blotting C Western blotting D Eastern blotting
Northern blotting
1) While other types exist, Type II restriction endonucleases are by far the most commonly used enzymes for genetic engineering.
T
10) One fundamental technique of genetic engineering includes the ability to cut DNA into random fragments.
T
11) Modification enzymes typically methylate specific bases within the recognition sequence to prevent digestion of the nucleotide sequence by restriction endonucleases.
T
13) Developing vaccines for humans relies heavily on manipulating and engineering vectors.
T
14) 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
15) Due to well developed molecular tools and careful screening designs, functional genes can be isolated directly by isolation from the environment rather than cultivating the diverse species in a microbial community.
T
16) 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
17) 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
19) Artificially synthesizing DNA strands (e.g., oligonucleotide primers) involves the careful attachment of one nucleotide at a time to an immobilized sequence.
T
21) One method to circumvent issues with introns when expression eukaryotic gene is a bacterium is to simply clone the mature transcript.
T
22) If vaccinia viruses were not both immunogenic and relatively benign, they would likely not be a favored vehicle for vaccinations.
T
3) 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
4) Strong promoters used for genetic manipulation are usually regulated by specific molecules.
T
5) DNA polymerases from Escherichia coli cannot be used to artificially copy gene sequences with a thermocycler.
T
6) Although various codons often code for the same amino acid, it is important to choose the codon preferred by the expression host itself.
T
9) In principle, a type II restriction endonuclease with an 8-nucleotide recognition sequence should cut 1 in every 48 nucleotide positions.
T
Many restriction enzymes produce sticky ends, which are very useful for genetic engineering. What makes the ends sticky? AWhen the restriction enzyme cuts, it cuts the two strands of a double-stranded DNA molecule unevenly. This produces overhanging DNA nucleotides on each fragment. These overhanging fragments are complementary to each other or to other fragments produced using the same restriction enzyme. B When the restriction enzyme cuts, it separates the two strands of DNA in a similar manner to the way that the strands separate in a replication bubble. Whenever the two strands of a DNA molecule are pulled apart, complementary bases are separated that can easily come back together again. C After the restriction enzyme cuts the DNA strands, additional steps are used to add nucleotides to the ends of each strand. These newly added nucleotides can form hydrogen bonds to join with other strands. D Restriction enzymes cut the phosphodiester backbone of the DNA molecule. The broken bonds can easily re-form, rejoining the separated fragments.
When the restriction enzyme cuts, it cuts the two strands of a double-stranded DNA molecule unevenly. This produces overhanging DNA nucleotides on each fragment. These overhanging fragments are complementary to each other or to other fragments produced using the same restriction enzyme.
15) To estimate the total concentration of a beneficial bacterial species in yogurt, ________ would provide the quickest results.
qPCR
hat might be a reason that a researcher would decide to use Northern blotting instead of Southern blotting? A to compare the proteins present in different cells B to determine the extent to which a gene is being transcribed in a particular tissue C to determine whether gene amplification was used to increase transcription of a gene in a particular organism D to determine the extent to which a gene is being translated in a particular tissue
to determine the extent to which a gene is being transcribed in a particular tissue
