Deck 20: Dna Tools and Biotechnology

Question 1

How can a gene that contains introns be made shorter (but remain functional) for genetic engineering purposes?

A) using a restriction enzyme (endonuclease) to cut the gene into shorter pieces
B) using reverse transcriptase to reconstruct the gene from its mRNA
C) using DNA polymerase to reconstruct the gene from its polypeptide product
D) using DNA ligase to put together fragments of the DNA that code for a particular polypeptide

Answer 1

B

Question 2

A principal problem with inserting an unmodified mammalian gene into a plasmid and then getting that gene expressed in bacteria is that ________.

A) prokaryotes use a different genetic code from that of eukaryotes
B) bacteria translate only mRNAs that have multiple messages
C) bacteria cannot remove eukaryotic introns
D) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA

Answer 2

C

Question 3

Which of the following correctly lists the processes in order for one cycle of polymerase chain reaction (PCR)?

A) denature DNA; add fresh enzyme; anneal primers; add dNTPs; extend primers
B) anneal primers; denature DNA; extend primers
C) extend primers; anneal primers; denature DNA
D) denature DNA; anneal primers; extend primers

Answer 3

D

Question 4

The final step in a Sanger DNA sequencing reaction is to run the DNA fragments on a gel. What purpose does this serve?

A) It adds ddNTP to the end of each DNA fragment.
B) It changes the length of the DNA fragments.
C) It separates DNA fragments based on their charge.
D) It separates DNA fragments generated during the sequencing reaction based on one-nucleotide differences in their size.

Question 5

Which of the following methods would be most successful in attempting to introduce a particular piece of DNA into an animal cell?

A) electroporation followed by recombination
B) introducing a plasmid into the cell
C) infecting the mouse cell with a Ti plasmid
D) transcription and translation

Question 6

Use the figure to answer the following question. Which of the following enzymes was used to produce the molecule of DNA in the figure?

A) ligase
B) a restriction enzyme (endonuclease)
C) RNA polymerase
D) DNA polymerase

Question 7

Why is sequencing an entire genome, such as that of C. elegans, a nematode, important for genetic research?

A) It allows researchers to use the sequence to build a "better" nematode, which is resistant to disease.
B) It allows research on a group of organisms we do not usually care much about.
C) A sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates.
D) A sequence that is found to have no introns in the nematode genome is likely to have acquired the introns from higher organisms.

Question 8

For which of the following processes can dideoxyribonucleotides be used?

A) to separate different sized DNA fragments
B) to produce cDNA from mRNA
C) to sequence a DNA fragment
D) to visualise DNA expression

Question 9

Why is it so important to be able to amplify DNA fragments when studying genes?

A) Before amplification, DNA fragments are likely to bind to RNA and would no longer be able to be analysed.
B) A gene may represent only a millionth of the cell's DNA.
C) Restriction enzymes (endonucleases) cut DNA into fragments that are too small.
D) A clone requires multiple copies of each gene per clone.

Question 10

Use the figure to answer the following question. The segment of DNA shown in the figure has restriction sites I and II, which create restriction fragments A, B and C. Which of the gels produced by electrophoresis best represents the separation and identity of these fragments?

A)

B)

C)

D)

Question 11

Many identical copies of genes cloned in bacteria are produced as a result of which of the following processes?

A) plasmid replication
B) bacterial cell reproduction
C) transformation
D) plasmid and bacterial cell reproduction

Question 12

How have DNA microarrays made a huge impact on genomic studies?

A) They can be used to eliminate the function of any gene in the genome.
B) They can be used to introduce entire genomes into bacterial cells.
C) They allow the expression of many or even all of the genes in the genome to be compared at once.
D) They allow physical maps of the genome to be assembled in a very short time.

Question 13

What information is critical to the success of polymerase chain reaction (PCR) itself?

A) The DNA sequence of the ends of the DNA to be amplified must be known.
B) The complete DNA sequence of the DNA to be amplified must be known.
C) The sequence of restriction-enzyme recognition sites in the DNA to be amplified must be known.
D) The sequence of restriction-enzyme recognition sites in the DNA to be amplified and in the plasmid where the amplified DNA fragment will be cloned must be known.

Question 14

Which of the following sequences is most likely to be cut by a restriction enzyme?

A) 5′-AATTCT 3′ 3′-TTAAGA-5′
B) 5′-AATATT-3′ 3′-TTATAA-5′
C) 5′-AAAATT-3′ 3′-TTTTAA-5′
D) 5′-ACTACT-3′ 3′-TGATGA-5′

Question 15

What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium?
I) Transform bacteria with a recombinant DNA molecule.
II) Cut the plasmid DNA using restriction enzymes (endonucleases).
III) Extract plasmid DNA from bacterial cells.
IV) Hydrogen-bond the plasmid DNA to non-plasmid DNA fragments.
V) Use ligase to seal plasmid DNA to non-plasmid DNA.

A) II, III, V, IV, I
B) III, II, IV, V, I
C) III, IV, V, I, II
D) IV, V, I, II, III

Question 16

Why are yeast cells frequently used as hosts for cloning?

A) They easily form colonies.
B) They can remove exons from mRNA.
C) They do not have plasmids.
D) They are eukaryotic cells.

Question 17

Which of the following enzymes is required to make complementary DNA (cDNA) from RNA?

A) restriction enzymes (endonucleases)
B) helicase
C) DNA ligase
D) reverse transcriptase

Question 18

Which of the following characteristics of Taq polymerase make it useful in the PCR process?

A) It is heat stable and can withstand the heating step of PCR.
B) Only minute amounts are needed for each cycle of PCR.
C) It binds more readily than other polymerases to the primers.
D) It has regions that are complementary to the primers.

Question 19

Pax-6 is a gene that is involved in eye formation in many invertebrates, such as Drosophila. Pax-6 is also found in vertebrates. A Pax-6 gene from a mouse can be expressed in a fly and the protein (PAX-6) leads to a compound fly eye. This information suggests which of the following characteristics of this gene?

A) Pax-6 genes are identical in nucleotide sequence.
B) PAX-6 proteins have identical amino acid sequences.
C) Pax-6 is highly conserved and shows shared evolutionary ancestry.
D) PAX-6 proteins are different for formation of different kinds of eyes.

Question 20

Which of the following processes helps bacterial cells protect their own DNA from restriction enzymes (endonucleases)?

A) adding methyl groups to adenines and cytosines
B) using DNA ligase to seal the bacterial DNA into a closed circle
C) adding histones to protect the double-stranded DNA
D) forming "sticky ends" of bacterial DNA to prevent the enzyme (endonuclease) from attaching

Question 21

In a comparison of two DNA sequences found in the same location on homologous chromosomes, one of the homologues carries the sequence 5′-AACTACGA-3′, and the other homologue carries the sequence 5′-AACTTCGA-3′. Within a population, you discover that each of these sequences is common. Which of the following statements correctly describes theses sequences?

A) They contain a SNP that may be useful for genetic mapping.
B) They can identify a protein-coding region of a gene.
C) They may cause disease.
D) They may carry out RNA interference.

Question 22

Which of the following processes uses labelled probes to visualise the expression of genes in whole tissues and organisms?

A) RT-PCR
B) in situ hybridisation
C) DNA microarrays
D) RNA interference

Question 23

Suppose that a researcher is successful at producing induced pluripotent stem cells (iPS) for replacement of pancreatic insulin-producing cells for people with type 1 diabetes. Which of the following could still pose problems for this individual?
I) the possibility that, once introduced into the patient, the iPS cells produce non-pancreatic cells
II) the failure of the iPS cells to take up residence in the pancreas
III) the inability of the iPS cells to respond to appropriate regulatory signals

A) I only
B) II only
C) III only
D) I, II, and III

Question 24

Which of the following processes is most like the formation of identical twins?

A) cell cloning
B) therapeutic cloning
C) use of adult stem cells
D) organismal cloning

Question 25

Which of the following statements correctly describes how RNA interference (RNAi) silences selected genes?

A) Synthetic double-stranded RNA molecules stop transcription from occurring.
B) Synthetic double-stranded RNA molecules stop DNA replication from occurring.
C) Synthetic double-stranded RNA molecules trigger the breakdown of a gene's messenger RNA.
D) Synthetic double-stranded RNA molecules stop mitosis from occurring.

Question 26

Reproductive cloning of human embryos is generally considered unethical. However, on the subject of therapeutic cloning, there is a wider divergence of opinion. Which of the following statements provides a likely explanation?

A) The use of adult stem cells is likely to produce more cell types than the use of embryonic stem cells.
B) Cloning to produce embryonic stem cells may lead to great medical benefits for many.
C) Cloning to produce stem cells relies on a different initial procedure than reproductive cloning.
D) A clone that lives until the blastocyst stage does not yet have human DNA.

Question 27

The first cloned cat, called Carbon Copy, was a calico, but she looked significantly different from her female parent. Why was this the case with this clone?

A) The cloning was done poorly and it was likely that some contaminating cat DNA became part of Carbon Copy's genome.
B) Fur colour genes in cats is determined by differential acetylation patterns.
C) Cloned animals have been found to have a higher frequency of transposon activation.
D) X chromosome inactivation in the embryo is random and produces different patterns.

Question 28

For a particular microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumour biopsies. Which of the following types of evidence will researchers be looking for in order to determine if the cells are cancerous?

A) a particular gene that is amplified in all or most of the patient samples
B) a pattern of fluorescence that indicates which cells are over proliferating
C) a pattern shared among some or all of the samples that indicates gene expression differing from control samples
D) a group of cDNAs that match those in non-breast cancer control samples from the same population

Question 29

Scientists developed a set of guidelines to address the safety of DNA technology. Which of the following safety measures is one that has been adopted by researchers?

A) Microorganisms used in recombinant DNA experiments must be genetically crippled to ensure that they cannot survive outside of the laboratory.
B) Genetically modified organisms are not allowed to be part of our food supply.
C) Transgenic plants are engineered so that the plant genes cannot hybridise.
D) Experiments involving HIV or other potentially dangerous viruses have been banned.

Question 30

One possible use of transgenic plants is in the production of human proteins, such as vaccines. Which of the following issues is a possible hindrance that must be overcome in order for this process to work properly?

A) prevention of transmission of plant allergens to the vaccine recipients
B) prevention of vaccine-containing plants being consumed by insects
C) use of plant cells to translate non-plant-derived mRNA
D) inability of the human digestive system to accept plant-derived protein

Question 31

Which of the following statements describes one of the technical reasons why gene therapy is problematic in humans?

A) Most cells with an engineered gene do not produce gene product.
B) Cells with transferred genes are unlikely to replicate.
C) Transferred genes may not have appropriately controlled activity.
D) mRNA from transferred genes cannot be translated.

Question 32

Which of the following statements correctly describes one of the main differences between embryonic stem cells and adult stem cells?

A) Embryonic stem cells only differentiate into only eggs and sperm, and adult stem cells differentiate into any type of cell.
B) Embryonic stem cells can give rise to all cell types in the organism, and adult stem cells cannot.
C) Embryonic stem cells can continue to reproduce for an indefinite period, and adult stem cells cannot.
D) One aim of using embryonic stem cells is to provide cells for repair of diseased tissue.

Question 33

In large scale, genome-wide association studies in humans, what types of genetic markers do researchers look for?

A) lengthy sequences that might be shared by most members of a population
B) SNPs where one allele is found more often in persons with a particular disorder than in healthy controls
C) SNPs where one allele is found in families with a particular introns sequence
D) SNPs where one allele is found in two or more adjacent genes

Question 34

In animals, what is the difference between reproductive cloning and therapeutic cloning?

A) Reproductive cloning uses totipotent cells, whereas therapeutic cloning does not.
B) Reproductive cloning uses embryonic stem cells, whereas therapeutic cloning does not.
C) Therapeutic cloning uses nuclei of adult cells transplanted into enucleated unfertilised eggs.
D) Therapeutic cloning supplies cells for repair of diseased or injured organs.

Question 35

Which of the following statements correctly describes one characteristic of genetically engineered plants?

A) They are more difficult to develop than genetically engineered animals.
B) They include transgenic rice plants that can grow in water more salty than seawater.
C) They are used in research but not yet in commercial agricultural production.
D) They are banned throughout the world.

Question 36

RNAi methodology uses double-stranded pieces of RNA to trigger breakdown of a specific mRNA or inhibit its translation. For which of the following processes might this technique be useful?

A) to decrease the production from a harmful mutated gene
B) to destroy an unwanted allele in a homozygous individual
C) to form a knockout organism that will not pass the deleted sequence to its progeny
D) to raise the concentration of a desired protein

Question 37

In 1997, Dolly the sheep was cloned. Which of the following processes was used?

A) replication and dedifferentiation of adult stem cells from sheep bone marrow
B) separation of an early stage sheep blastula into separate cells, one of which was incubated in a surrogate ewe
C) transfer of an adult cell's nucleus into an enucleated sheep egg, followed by incubation in a surrogate
D) isolation of stem cells from a lamb embryo and production of a zygote equivalent

Question 38

In recent times, it has been shown that adult cells can be induced to become pluripotent stem cells (iPS). To make this conversion, what has been done to the adult cells?

A) A retrovirus is used to introduce four specific master regulatory genes.
B) The adult stem cells must be fused with embryonic cells.
C) Cytoplasm from embryonic cells is injected into the adult cells.
D) The nucleus of an embryonic cell is used to replace the nucleus of an adult cell.

Question 39

A researcher is using adult stem cells and comparing them to other adult cells from the same tissue. Which of the following findings is likely from this comparison?

A) The cells from the two sources exhibit different patterns of DNA methylation.
B) Adult stem cells have more DNA nucleotides than their counterparts.
C) The two kinds of cells have virtually identical gene expression patterns in microarrays.
D) The non-stem cells have fewer repressed genes.

Question 40

Which of the following problems with animal cloning might result in premature death of the clones?

A) use of pluripotent instead of totipotent stem cells
B) use of nuclear DNA as well as mtDNA
C) abnormal gene regulation due to variant methylation
D) the indefinite replication of totipotent stem cells

Question 41

One predicted aspect of climate change is that climates, including precipitation and temperature, over most of Earth will become more variable. Which of the following is a good strategy for genetically engineering crops if this is true?

A) Use only plant crops that are genetically engineered.
B) Genetically engineer most crops to withstand very long droughts.
C) Genetically engineer several genotypes within single crop types.
D) Genetically engineer the fastest growing crops possible.

Question 42

Why might using retroviral vectors for gene therapy increase the patient's risk of developing cancer?

A) Retroviral vectors may introduce proteins from the virus.
B) Retroviral vectors do not express the genes that were introduced into a patient's cells.
C) Retroviral vectors do not integrate their recombinant DNA into the patient's genome.
D) Retroviral vectors integrate recombinant DNA into the genome in ways that may misregulate the expression of genes at or near the site of integration.

Question 43

Use the following information to answer the question.
In an experiment, DNA from the linear form of the bacteriophage Lambda was cut into fragments using the restriction enzyme Hind III. Hind III cuts the Lambda DNA between the adenine nucleotides on the complementary strands in a specific sequence, as indicated in the diagram, producing eight different size fragments. These fragments are then separated with an electrical current based on size after the DNA fragments are placed in a porous gel, a process called gel electrophoresis.
Select an observation that best describes a correct aspect of the two processes of restriction
Digest and gel electrophoresis.

A) When separated on a gel, the pattern of DNA bands will be characteristic of those cut with Hind III; different restriction enzymes will not produce these same fragments.
B) The sequence 5′-AAGCTT-3′ is found eight times in the Lambda genome, and the restriction enzyme Hind III finds each location.
C) If an electrical current is not used, eight separate DNA bands would be visible, but they would not be separated as much as when an electrical current is used.
D) Only the restriction enzyme Hind III can be used to cut Lambda DNA since restriction enzymes are specific to the type of DNA they can cut.

Question 44

In the form of gene therapy used successfully for severe combined immunodeficiency syndrome, SCID-X1, how is the genetic engineering of human cells achieved?

A) by injecting engineered viruses into the patient's bloodstream
B) by injecting engineered viruses into the patient's bone marrow
C) by treating a relative's cultured bone marrow cells with genetically engineered viruses and then injecting these cells into the patient's bone marrow
D) by isolating the patient's bone marrow cells, infecting them with genetically engineered viruses, and injecting them back into the patient's bone marrow

Question 45

Plants are more readily manipulated by genetic engineering than are animals because

A) plant genes do not contain introns.
B) more vectors are available for transferring recombinant DNA into plant cells.
C) a somatic plant cell can often give rise to a complete plant.
D) plant cells have larger nuclei.

Question 46

Which of the following characteristics of short tandem repeats (STRs) DNA makes it useful for DNA fingerprinting?

A) The number of repeats is highly variable from person-to-person or animal-to-animal.
B) The sequence of DNA that is repeated varies significantly from individual-to-individual.
C) The sequence variation is acted upon differently by natural selection in different environments.
D) Every racial and ethnic group has inherited different short tandem repeats.

Question 47

Which of the following tools of DNA technology is incorrectly paired with its use?

A) electrophoresis-separation of DNA fragments
B) DNA ligase-cutting DNA, creating sticky ends of restriction fragments
C) DNA polymerase-polymerase chain reaction to amplify sections of DNA
D) reverse transcriptase-production of cDNA from mRNA

Question 48

Use the following information to answer the question.
Organisms share many conserved core processes and features, including transcription and translation, using a uniform genetic code. Scientists have used these shared processes and features in biotechnology. For example, for the process of some transformations, a plasmid is constructed when a eukaryotic gene of interest is added with an antibiotic resistant gene such as beta-lactamase, which is used for ampicillin resistance. This plasmid is then inserted into a prokaryotic bacterial cell, such as E. coli, through a transformation process that leads to the production of the product protein from the eukaryotic organism. To culture the bacteria and obtain the protein product, the bacteria must grow.
Select the appropriate condition to determine if the plasmid has entered the E. coli bacterial cell.

A) nutrient broth to which no antibiotic has been added
B) water to which ampicillin has been added
C) nutrient broth to which ampicillin has been added
D) nutrient broth to which other resistant bacteria have been added

Question 49

DNA technology has many medical applications. Which of the following is not done routinely at present?

A) production of hormones for treating diabetes and dwarfism
B) analysis of gene expression for more informed cancer treatments
C) gene editing by the CRISPR-Cas9 system in viable human embryos to correct genetic diseases
D) prenatal identification of genetic disease alleles

Question 50

Which of the following information or processes does gene therapy require?

A) the knowledge and availability of the defective gene but not the normal allele
B) the ability to introduce the normal allele into the patient
C) the ability to express the introduced gene at any time in the tissue site within the patient
D) the ability to introduce a defective allele into a patient

Question 51

What is the most favourable characteristic of retroviruses that makes them useful in gene therapy applications?

A) Retroviruses have an RNA genome.
B) Retroviruses possess reverse transcriptase.
C) DNA copies of retroviral genomes become integrated into the genome of the infected cell.
D) Retroviruses mutate often.

Question 52

Expression of a cloned eukaryotic gene in a bacterial cell involves many challenges. The use of mRNA and reverse transcriptase is part of a strategy to solve the problem of

A) post-transcriptional processing.
B) post-translational processing.
C) nucleic acid hybridisation.
D) restriction fragment ligation.

Question 53

A paleontologist has recovered a bit of tissue from the 400-year-old preserved skin of an extinct dodo (a bird). To compare a specific region of the DNA from a sample with DNA from living birds, which of the following would be most useful for increasing the amount of dodo DNA available for testing?

A) SNP analysis
B) polymerase chain reaction (PCR)
C) electroporation
D) gel electrophoresis

Question 54

Which of the following is not true of cDNA produced using human brain tissue as the starting material?

A) It can be amplified by the polymerase chain reaction.
B) It was produced from pre-mRNA using reverse transcriptase.
C) It can be labelled and used as a probe to detect genes expressed in the brain.
D) It lacks the introns of the pre-mRNA.

Question 55

In DNA technology, the term vector can refer to

A) the enzyme that cuts DNA into restriction fragments.
B) the sticky end of a DNA fragment.
C) a SNP marker.
D) a plasmid used to transfer DNA into a living cell.

Question 56

Transgenic mice are useful to human researchers because they ________.

A) can be valuable animal models of human disease
B) are essential for mapping human genes
C) are now used in place of bacteria for cloning human genes
D) were instrumental in pinpointing the location of the huntingtin gene

Question 57

Which of the following sequences in double-stranded DNA is most likely to be recognised as a cutting site for a restriction enzyme?

A) AAGG TTCC
B) GGCC CCGG
C) ACCA TGGT
D) AAAA TTTT