Chapter 20 Review

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

5'-AATATT-3' 3'-TTATAA-5'

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

A gene may represent only a millionth of the cell's DNA.

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

A pattern shared among some or all of the samples that indicates gene expression differing from control samples.

In DNA technology, the term vector can refer to ______________.

A plasmid used to transfer DNA into a living cell.

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 restriction enzyme (endonuclease)

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 retrovirus is used to introduce four specific master regulatory genes.

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

A sequence that is found to have a particular function in the nematode is likely to have a closely related function in the nematode is likely to have a closely related function in vertebrates.

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

A somatic plant cell can often give rise to a complete plant.

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

Abnormal gene regulation due to variant methylation.

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

Adding methyl groups to adenines and cytosines.

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

Bacteria cannot remove eukaryotic introns

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

By isolating the patient's bone marrow cells, infecting them with genetically engineered viruses, and injecting them back into the patient's bone marrow.

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?

Cloning to produce embryonic stem cells may lead to great medical benefits for many.

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

DNA copies of retroviral genomes become integrated into the genome of the infected cell.

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

DNA ligase-cutting DNA, creating sticky ends of restriction fragments.

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

Denature DNA; anneal primers; extend primers

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

Electroporation followed by recombination

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

Embryonic stem cells can give rise to all cell types in the organism, and adult stem cells cannot.

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

GGCC CCGG

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

Gene editing by the CRISPR-Cas9 system in viable human embryos to correct genetic diseases.

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?

Genetically engineer several genotypes within single crop types.

Suppose that a researcher is successful at producing induced pluripotent stem cells (iPS) for the 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

I, II, and III.

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.

III, II, IV, V, I

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

In situ hybridization

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

It is the heat stable and can withstand the heating step of PCR.

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

It separates DNA fragments generated during the sequencing reaction based on one-nucleotide differences in their size.

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

It was produced from pre-mRNA using reverse transcriptase.

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?

Microorganisms used in recombinant DNA experiments must be genetically crippled to ensure that they cannot survive outside of the laboratory.

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?

Negative - C ___A__B - Positive

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.

Nutrient broth to which ampicillin has been added.

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

Organismal cloning

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?

Pax-6 is highly conserved and shows shared evolutionary ancestry.

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

Plasmid and bacterial cell reproduction.

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?

Polymerase chain reaction (PCR)

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 ________________________.

Post-transcriptional processing.

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

Retroviral vectors integrate recombinant DNA into the genome in ways that may misregulate the expression of genes at or near the site of integration.

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

Reverse transcriptase

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

SNPs where one allele is found more often in persons with a particular disorder than in healthy controls.

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

Synthetic double-stranded RNA molecules trigger the breakdown of a gene's messenger RNA.

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

The DNA sequence of the ends of the DNA to be amplified must be known.

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

The ability to introduce the normal allele into the patient.

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?

The cells from the two sources exhibit different patterns of DNA methylation.

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

The number of repeats is highly variable from person to person or animal to animal.

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

Therapeutic cloning supplies cells for repair of diseased or injured organs.

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

They allow the expression of many or even all of the genes in the genome to be compared at once.

Why are yeast cells frequently used as hosts for cloning?

They are eukaryotic cells.

In a comparison of two DNA sequences found in the same location on homologous chromosomes, one of the homologs carries the sequence 5′-AACTACGA-3′, and the other homolog carries the sequence5′-AACTTCGA-3′. Within a population, you discover that each of these sequences is common. Which of the following statements correctly describes theses sequences?

They contain a SNP that may be useful for genetic mapping.

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

They include transgenic rice plants that can grow in water more salty than seawater.

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?

To decrease the production from a harmful mutated gene.

For which of the following processes can dideoxyribonucleotides be used?

To sequence a DNA fragment.

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

Transfer of an adult cell's nucleus into an enucleated sheep egg, followed by incubation in a surrogate.

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

Transferred genes may not have appropriately controlled activity.

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?

Use of plant cells to translate non-plant-derived mRNA.

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

Using reverse transcriptase to reconstruct the gene from its mRNA.

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 the correct aspect of the two processes of restriction digest and gel electrophoresis.

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.

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?

X chromosome inactivation in the embryo is random and produces different patterns.

Transgenic mice are useful to human researchers because they ________.

can be valuable animal models of human disease.