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Q:
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A biologist has isolated the mRNA used for the translation of a particular protein. He wants to transform the gene for the protein into another organism, for which he needs DNA strands. Which of the following enzymes is most adequately suited to this task? |
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A
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reverse transcriptase |
B
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DNA polymerase |
C
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topoisomerase |
D
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transcriptomerase |
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Tags:
Genetic Code, Transcription, Translation | Recombinant DNA and Biotechnology | Viruses | |
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| 4 |
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Q:
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Fermentation of recombinant eukaryotic proteins is often done in prokaryotes. Which of the following is not a problem or risk associated with using prokaryotic systems for expression of eukaryotic proteins? |
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A
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Prokaryotes do not post-translationally modify their proteins and cannot perform glycosylation or specialized folding tasks. |
B
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Prokaryotes contain endotoxin which must be extracted thoroughly before it can be used for human applications. |
C
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Prokaryotes may not use the same codons as found on the eukaryotic DNA and thus may not have certain tRNAs, resulting in premature termination of translation. |
D
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Prokaryotes have a high frequency of integrating DNA into their chromosomes which blocks transcription almost entirely. |
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Tags:
Recombinant DNA and Biotechnology | Prokaryotes | |
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| 5 |
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Q:
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Competent bacteria cells are capable of taking up plasmids. A scientist in a lab intends to amplify a specific plasmid by transforming a competent strain of bacteria with the plasmid in question and then letting the bacteria divide. The scientist can then isolate the bacterial genetic material, which includes now includes the plasmid. The plasmid also encodes a gene for ampicillin resistance (which is not encoded in the competent bacteria cells), allowing transformed bacteria to grow on agar plates containing ampicillin. A negative control is used to determine if a confounding variable is affecting an experiment's results. Negative controls are groups in which we would not expect a result when applying all of the experiment`s conditions except for the independent variable. Which of the following can act as a negative control to ensure that the bacteria that grow on the agar containing ampicillin are transformed bacteria? |
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A
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Just distilled water |
B
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Just competent bacteria cells |
C
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Just plasmid |
D
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Just bacterial cells and plasmid |
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Tags:
Recombinant DNA and Biotechnology | Prokaryotes | |
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| 6 |
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Q:
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Recombinant plasmids are used to clone gene fragments encoding desired proteins. They are constructed by cutting the plasmid vector (containing an ampicillin resistance gene) and gene insertion fragments with restriction enzymes such that the end fragments of the cut sites match with each other. The cut plasmid vector and insertion fragment are then ligated together with the enzyme ligase to form the recombinant plasmid. This recombinant plasmid can be transformed into competent bacteria and plated onto agar plates with ampicillin, where only bacterial colonies with the recombinant plasmids can grow. Colonies can then be picked and have their recombinant plasmids amplified via PCR (polymerase chain reaction).
In which the following experimental conditions will we not expect bacteria colonies to grow on agar plates with ampicillin?
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A
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Competent bacteria mixed with a plasmid vector which has been cut with two different restriction enzymes (resulting in nonidentical cut sites), and reacted with ligase. |
B
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Competent bacteria mixed with uncut plasmid vector. |
C
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Competent bacteria mixed with cut plasmid vector and insertion fragment with ligase. |
D
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Competent bacteria mixed with plasmid vector cut with a single restriction enzyme and reacted with ligase. |
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Tags:
Recombinant DNA and Biotechnology | Prokaryotes | |
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| 7 |
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Q:
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A bacterium has been genetically transformed with human Gene A which consists of approximately 800 nucleotides. During expression, researchers notice that the protein is not being translated; only fragments of approximately 50 amino acids are formed. Genetic sequencing shows there are no nonsense mutations in the gene sequence. Which of the following is a plausible explanation for the observation? |
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A
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The bacterium lacks the tRNA that corresponds to the particular codon for the 51st amino acid. |
B
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The bacterial ribosome is incompatible with the human mRNA and cannot properly translate the protein. |
C
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The bacterium is unable to glycosylate the protein, terminating translation early. |
D
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The human gene is too long; bacteria can only synthesize proteins up to approximately 50 amino acids. |
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Tags:
Recombinant DNA and Biotechnology | Prokaryotes | |
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| 8 |
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Q:
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A plasmid contains genes for ampicillin and kanamycin resistance. A restriction endonuclease is used to cut the plasmid within the ampR gene before ligating in a gene fragment, that shares the same restriction sites cut by the endonuclease, encoding green fluorescent protein (GFP). The product from this plasmid construct experiment is then transformed into competent bacteria, which are allowed to grow and replicate over a period of time. These bacteria are then smeared on agar plates containing kanamycin. The next day, several bacterial colonies are observed to grow on the plates. Viewed under a fluorescent microscope, fluorescence is observed. Which of the following is true about all of the bacterial colonies that are growing on the agar plates? |
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A
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They all contain the plasmid construct containing GFP. |
B
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They all exhibit ampicillin resistance. |
C
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They all have kanamycin antibiotic resistance |
D
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None of the above is true. |
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Tags:
Recombinant DNA and Biotechnology | |
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| 9 |
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Q:
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Two different restriction enzymes cut at specific sequence sites on DNA fragments. The cut DNA fragments are then placed with DNA ligase to ligate compatible fragments. Which of four fragments will ligate with the following fragment:
-C
-GTTACA
Note: The dashes indicate continuing sequence. |
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A
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-CTGTAA
-G
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B
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-AATGT
-T
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C
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-TGTAA
-A
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D
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-CAATGT
-G
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Tags:
DNA Replication and Repair | Recombinant DNA and Biotechnology | |
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| 10 |
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Q:
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Enzymatic DNA sequencing reactions are prepared primarily by adding DNA Polymerase, deoxynucleotide phosphates (dNTPs), double-deoxynucleotide phosphates (ddNTPs), and a DNA template. A ddNTP serves to terminate the polymerization reaction once it is added to the growing chain. Since this occurs randomly, various fragment lengths are generated which are then observed using PCR. What is the most likely mechanism by which ddNTPs terminate the polymerization reaction? |
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A
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ddNTPs lack a 5' OH in addition to a 2' OH. Thus, ddNTPs cannot be added to the growing DNA molecule, and polymerization terminates. |
B
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ddNTPs lack a 5' OH in addition to a 2' OH. Thus, they can only be added to the growing end of the DNA molecule via their 3' OH, and polymerization terminates because DNA synthesis can only occur 5' to 3'. |
C
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ddNTPs lack a 3' OH in addition to a 2' OH. Thus, once they are added to the growing end of the DNA molecule, there is no OH on which to add new nucleotides and polymerization terminates. |
D
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ddNTPs lack a 3' OH in addition to a 2' OH. Thus, once they are added to the growing end of the DNA molecule, only ddNTPs can continue to be added. The reaction terminates due to the lack of further ddNTPs present in the reaction mixture. |
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Tags:
DNA Replication and Repair | Recombinant DNA and Biotechnology | |
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| 11 |
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Q:
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Which of the following is true regarding using dideoxynucleotides (ddNTPs) for DNA sequencing?
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A
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Restriction enzymes cut the target DNA into fragments, which are then separated and visualized with electrophoresis
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B
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The template strand is tagged with a radioactive isotope
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C
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ddATPs, ddCTPs, ddGTPs, and ddTTPs must be utilized in a separate environment from the dATPs, dCTPs, dGTPs, and dTTPs
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D
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A ddTTP can randomly and occasionally terminate the synthesis of DNA where an adenine occurs in the template strands
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Tags:
Recombinant DNA and Biotechnology | Nucleic Acid Structure and Function | DNA Replication and Repair | |
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| 12 |
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Q:
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Which of the following is not a step in polymerase chain reaction (PCR)? |
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A
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Addition of a DNA polymerase |
B
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Addition of restriction enzymes to cleave DNA |
C
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Applying heat to denature the DNA |
D
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Lowering of temperature to allow annealing of primers to DNA |
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Tags:
Recombinant DNA and Biotechnology | |
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| 13 |
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Q:
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Which of the following best describes the difference between embryonic stem cells and adult stem cells in animals? |
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A
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Embryonic stem cells have fewer genes than adult stem cells
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B
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Embryonic stem cells only undergo meiosis whereas adult stem cells can undergo meiosis and mitosis
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C
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Embryonic stem cells give rise to more tissue types than adult stem cells do
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D
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Compared to adult stem cells which are spread throughout the entire body, embryonic stem cells are localized to specific sites within the embryo
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Tags:
Eukaryotic Cells | Recombinant DNA and Biotechnology | |
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| 14 |
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Q:
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A cDNA library differs from a genome in that it:
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A
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Contains only coding sequences of DNA. |
B
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Contains only the complementary strands of coding DNA sequences. |
C
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Contains only introns with the exons removed. |
D
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Contains only foreign DNA fragments and none of the native host fragments. |
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Tags:
Recombinant DNA and Biotechnology | |
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| 15 |
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Q:
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How many copies of a DNA fragment would be expected to be created after 5 cycles of PCR, assuming that the process began with a single fragment? |
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Tags:
Recombinant DNA and Biotechnology | |
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| 16 |
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Q:
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Restriction enzymes are responsible for: |
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A
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termination of translation. |
B
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termination of transcription. |
C
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methylation of DNA. |
D
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cleavage of DNA strands. |
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Tags:
Recombinant DNA and Biotechnology | |
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| 17 |
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Q:
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Which of the following holds true regarding polymerase chain reaction (PCR)? |
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A
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Primers are absolutely necessary in PCR experiments. |
B
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After 8 rounds of PCR, there will be 9 total copies of DNA. |
C
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Non-human DNA polymerases must be utilized. |
D
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The first step in PCR is to drastically decrease the temperature of a solution of DNA fragments. |
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Tags:
Recombinant DNA and Biotechnology | |
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| 18 |
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Q:
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Which of the following is true regarding cDNA (complementary DNA) as used in gene cloning? |
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A
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reverse transcriptase is required to make DNA from the mRNA of interest |
B
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they are typically used to clone prokaryotic genes in eukaryotes |
C
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cDNA contains RNA bases |
D
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cDNA is synthesized from single stranded DNA |
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Tags:
Recombinant DNA and Biotechnology | |
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