Gene cloning is crucial to any application involving one gene because _____. ( Concept 20.1)
A)naturally occurring DNA molecules are very long and contain many genes
B)it provides a means to produce large quantities of its protein product
C)genes occupy only a small proportion of the chromosomal DNA in eukaryotes, the rest being noncoding nucleotide sequences
D)it provides a means to produce many copies of a gene in short period of time
E)All of the listed responses are correct.
E
What is an advantage to using a bacterial artificial chromosome (BAC) for generating a genomic library compared to a plasmid or phage that has historically been used for this process? ( Concept 20.1)
A)BACs carry DNA fragments much larger than plasmids or phages and greatly minimize the number of clones needed to make up the genomic library.
B)The use of BACs reduces the frequency with which specific genes will be cut within the coding region by restriction enzymes and divided up among two or more clones.
C)Because of their size, BACs are much less difficult to work with in the lab than plasmids or phages.
D)The first and second responses listed are correct.
E)The first three listed responses are correct.
D
In which of the following would it be advantageous to create and work with a cDNA (complementary DNA) library rather than a genomic library? ( Concept 20.1)
A)a study of the role that noncoding RNA plays in regulating the expression of the coding genes of a genome
B)sequencing the enhancer region of a gene that regulates neural development of a frog
C)a study of a protein involved in eye development of a salamander and the regulation of the gene that expresses it
D)a comparison of the sequences of introns within a gene shared among different lineages of reptiles
E)A cDNA library would not be the appropriate choice for any of the listed responses.
C
The expression of the PAX-6 gene when vertebrate and fruit fly versions of the gene are exchanged between these animal groups illustrates _____. ( Concept 20.1)
A)that the same gene can have very different functions in different types of animals
B)that some coding genes have products other than proteins in different types of animals
C)the common ancestry in the evolution of these animal groups
D)that the mechanisms of gene expression vary among different animal groups
E)that a gene that plays a major role in the development of one type of organism often has a reduced role in another
C
Which of the following enzymes is key to the automation of PCR (polymerase chain reactions)? ( Concept 20.1)
A)DNA ligase
B)Taq polymerase
C)reverse transcriptase
D)restriction enzyme
E)human DNA polymerase
B
Bacteria use restriction enzymes to _____. ( Concept 20.1)
A)synthesize DNA
B)synthesize RNA
C)synthesize protein
D)destroy foreign protein
E)destroy foreign DNA
D
An enzyme that cuts DNA at a symmetrical sequence of bases is called _____. ( Concept 20.1)
A)reverse transcriptase
B)a restriction enzyme
C)cDNA
D)palindrome
E)ligase
B
When a typical restriction enzyme cuts a DNA molecule, the cuts are staggered so that the DNA fragments have single-stranded ends. This is important in recombinant DNA work because _____. ( Concept 20.1)
A)it allows a cell to recognize fragments produced by the enzyme
B)the single-stranded ends serve as starting points for DNA replication
C)the fragments will bond to other fragments with complementary single-stranded ends
D)it enables researchers to use the fragments as introns
E)only single-stranded DNA segments can code for proteins
C
In genetic engineering, "sticky end" refers to _____. ( Concept 20.1)
A)a technique for finding a gene of interest within a nucleus without destroying the cell
B)the ability of plasmids to stick to a bacterial cell wall and thus be taken up into the bacterium
C)short bits of single-stranded DNA left at the end of DNA molecules cut by restriction enzymes
D)the site on mRNA that sticks to the DNA during transcription
E)None of the listed responses is correct.
C
Which of the following enzymes could seal a nick in one strand of a double-stranded DNA molecule by creating a sugar-phosphate bond between the adjacent, unjoined nucleotides? ( Concept 20.1)
A)DNA ligase
B)reverse transcriptase
C)restriction enzyme
D)terminator enzyme
E)DNA polymerase
A
To create recombinant DNA with long-term stability, it is necessary to have which of the following in the test tube? ( Concept 20.1)
A)hydrogen bonding
B)DNA ligase
C)reverse transcriptase
D)DNA polymerase
E)heat-resistant DNA polymerase
B
What two enzymes are needed to produce recombinant DNA? ( Concept 20.1)
A)a restriction enzyme and a topoisomerase
B)a restriction enzyme and a ligase
C)a restriction enzyme and a polymerase
D)a polymerase and a ligase
E)a polymerase and a topoisomerase
B
In recombinant methods, the term "vector" refers to _____. ( Concept 20.1)
A)the enzyme that cuts DNA into restriction fragments
B)the sticky ends of a DNA fragment
C)an RFLP marker
D)a plasmid or other agent used to transfer DNA into a living cell
E)a DNA probe used to locate a particular gene
D
Which arrangement of the following four enzymes represents the order in which they would be used in a typical gene-cloning experiment resulting in the insertion of a cDNA into a bacterial plasmid? Begin with the gene's mRNA transcript. ( Concept 20.1)
A)restriction enzyme, reverse transcriptase, DNA polymerase, DNA ligase
B)restriction enzyme, DNA ligase, reverse transcriptase, DNA polymerase
C)reverse transcriptase, DNA polymerase, restriction enzyme, DNA ligase
D)reverse transcriptase, DNA ligase, DNA polymerase, restriction enzyme
E)reverse transcriptase, restriction enzyme, DNA polymerase, DNA ligase
C
A scientist wishing to create an organism capable of breaking down several kinds of toxic waste combines genes from several species of bacteria to create a single "superbacterium." Which of the following would be needed to do this? ( Concept 20.1)
A)nucleic acid probes
B)DNA ligase
C)plasmids
D)restriction enzymes
E)All of the listed responses are correct.
E
A nucleic acid probe is used to _____. ( Concept 20.1)
A)clone genes
B)produce a large amount of DNA from a tiny amount of DNA
C)make exact copies of DNA sequences
D)identify genes that have been inserted into bacterial plasmids or separated by electrophoresis
E)make DNA from RNA
D
What is the source of the reverse transcriptase used in recombinant DNA technology? ( Concept 20.1)
A)retroviruses
B)plant cells
C)cultured fungal cells
D)cultured phage-infected mammalian cells
E)either retroviruses or cultured phage-infected mammalian cells
A
Because eukaryotic genes contain introns, they cannot be translated by bacteria, which lack RNA-splicing machinery. But if you want to engineer a bacterium to produce a eukaryotic protein, you can synthesize a gene without introns. A good way to do this is to _____. ( Concept 20.1)
A)alter the bacteria so that they can splice RNA
B)use a nucleic acid probe to find a gene without introns
C)work backward from mRNA to make a version of the gene without introns
D)use a phage to insert the desired gene into a bacterium
E)use a restriction enzyme to remove introns from the gene
C
DNA synthesized using an RNA template is called _____. ( Concept 20.1)
A)reverse transcriptase
B)a restriction enzyme
C)cDNA
D)a palindrome
E)a plasmid
C
In the polymerase chain reaction (PCR), the sequence of bases in the primers is important because it _____. ( Concept 20.1)
A)determines which segment of the genome will be amplified
B)always matches a stop codon
C)always causes a silent mutation
D)determines how many cycles of the reaction are needed to obtain a sufficient amount of amplified DNA
E)determines the number of tandem repeats in a genome
A
A molecular biologist has isolated a short segment of DNA that she wants to replicate in vitro. First she heats the DNA, which separates the two strands, and then she adds _____. ( Concept 20.1)
A)nucleotides, primers, and polymerase
B)ribosomes, nucleosomes, and messenger RNA
C)nucleotides and ligase
D)transfer RNA, matching amino acids, and messenger RNA
E)ribosomes, matching amino acids, and primers
A
In the polymerase chain reaction (PCR) technique, a heating phase and a cooling phase alternate. An original sample of DNA would have to pass through how many total rounds of heating and cooling before a sample is increased eight times in quantity? ( Concept 20.1)
A)two
B)three
C)four
D)six
E)eight
B
Single nucleotide polymorphisms (SNPs) _____. ( Concept 20.2)
A)are single base-pair variations in the genomes of the human population
B)are genetic markers used to study the genetic basis for disease
C)are small nucleotide differences among individuals located in coding and non-coding sequences in the genome
D)can be the molecular basis for different alleles
E)All of the listed responses are correct.
E
Separating DNA fragments by gel electrophoresis is useful for which of the following? ( Concept 20.2)
A)identifying DNA fragments for RFLP analysis
B)purifying specific DNA fragments
C)distinguishing between different alleles of a gene
D)identifying a plasmid or a virus by examining its restriction fragment pattern
E)All of the listed responses are correct.
E
Southern blotting is _____. ( Concept 20.2)
A)a method of DNA amplification
B)a technique used to study RFLPs
C)how bacteria take up DNA from the surrounding solution
D)the insertion of DNA into a plant's chromosomes
E)used to determine the product of a particular gene
B
Which of the following is the first step of the Southern blotting procedure? ( Concept 20.2)
A)hybridizing the DNA with a radioactive probe
B)digesting the DNA with a restriction enzyme
C)separating the DNA fragments using gel electrophoresis
D)transferring the DNA to a blot
E)using the blot to expose photographic film
B
The dideoxyribonucleotide chain-termination method _____. ( Concept 20.2)
A)produces a ladder of DNA fragments, with each individual band labeled with one of four different fluorescent tags
B)can be used to sequence entire eukaryotic chromosomes in a single reaction
C)is very slow, requiring several weeks to determine a sequence of about 200 nucleotides
D)does not involve electrophoresis
E)is difficult to automate and must be performed under close human supervision
A
The term "RFLP" stands for _____. ( Concept 20.2)
A)restriction fragment length polymorphism
B)reverse fragment ligated polymerization
C)really fast ligation protocol
D)restriction fragment ligation procedure
E)RNA fragment length pool
A
RFLPs have been tremendously useful for genomic mapping studies because _____. ( Concept 20.2)
A)they are found only in the coding sequences of genes
B)they are found only in the promoter regions of genes
C)they are found only in disease-causing genes
D)they are not restricted to genes, and are abundantly scattered throughout the genome
E)they are found only in expressed genes
D
The efficiency of cloning, and the ability to generate healthy cloned animals, has been largely hampered by the difficulty of _____. ( Concept 20.3)
A)completely reversing epigenetic alterations in donor cell nuclei such as DNA methylation and chromatin packing
B)inducing recombination in differentiated donor cells in order to restore the full genomic complement
C)transforming donor cells with genes encoding proteins required for normal embryonic development
D)physically removing the nucleus from the egg cell that will ultimately receive the donor cell nucleus
E)implanting the clone into the surrogate mother
A
"Therapeutic cloning" refers to _____. ( Concept 20.3)
A)the use of cloned embryos as a source of stem cells that could be used to treat disease
B)treating patients with therapeutic proteins made using recombinant DNA technology
C)cloning animals to obtain organs that could be used for transplantation into humans
D)treating a genetic disease by obtaining cells from an individual with the disease, introducing genes into the cells in order to repair the genetic defect, and then reintroducing the cells back into the individual
E)All of the listed responses are correct.
A
Nuclear transplantation involves _____. ( Concept 20.3)
A)inserting a sperm cell into an egg cell in vitro
B)placing the nucleus from an egg cell into an enucleated somatic cell
C)removing the nucleus of an egg cell and replacing it with the nucleus of a somatic cell
D)the use of microarray analysis and RNA interference
E)the use of reverse transcriptase to make copies of the genes that are being expressed.
C
_____ can give rise to any type of cell whereas _____ can give rise to a subset of cell types. ( Concept 20.3)
A)Heterozygous cells ... homozygous cells
B)Adult stem cells ... embryonic stem cells
C)Embryonic stem cells ... adult stem cells
D)Totipotent cells ... nerve cells
E)Adult stem cells ... totipotent cells
C
During the process of differentiation, cells _____. ( Concept 20.3)
A)lose genes
B)exchange DNA with other cells via the process of horizontal gene transfer
C)gain and lose genes, depending on what type of cell they will become
D)express different genes in response to cell signaling
E)randomly turn on and off genes until the right combination is reached
D
Dolly, the sheep, was cloned from an adult cell. She had a number of health problems and died at a relatively young age. Three mules that were born in 2003 were cloned from fetal cells. If it turns out that the mules remain healthy and live normal lives, how would this outcome tie in with Gurdon's observations with tadpoles? ( Concept 20.3)
A)Gurdon found no correlation between the age of the donor cells and the ability of the transplanted nucleus to direct development.
B)Gurdon found that nuclei from older donor cells were more likely to correctly direct differentiation and give rise to healthy tadpoles.
C)Gurdon found a positive correlation between the age of the donor nuclei and the ability of the nuclei to direct differentiation.
D)Gurdon found that the ability of a transplanted nucleus to direct normal development was inversely related to the age of the donor.
E)None of the listed responses is correct.
D
All of the following are true regarding induced pluripotent stem (iPS) cells except _____. ( Concept 20.3)
A)iPS cell technology may provide a more morally acceptable approach to therapeutic cloning
B)iPS cells have been demonstrated to function identically to embryonic stems cells
C)the reprogramming of diseased cells in humans to form iPS cells could provide model systems for studying the origins of the disease
D)iPS cell technology could offer the potential to regenerate nonfunctional or diseased tissues and avoid the risk of transplant rejection in the diseased patient
E)iPS cells are formed by added genes to the genome of differentiated skin cells
B
All of the following are current applications of DNA technology in medicine except _____. ( Concept 20.3)
A)clinical use of iPS cells harvested from organ-impaired individuals for the culturing and transplantation of a functioning organ in the diseased individual
B)use of genome-wide association studies to identify SNPs (single-nucleotide polymorphisms) linked to disease
C)use of microarray assays to analyze the expression patterns of genes associated a type of cancer
D)use of retroviruses to introduce normal alleles of genes into diseased cells for disorders involving one defective gene
E)genetically engineering organisms, from bacteria to goats, into protein factories that produce vital human proteins such as insulin, anticlotting agents, and human growth hormone
A
A genetic marker is _____. ( Concept 20.4)
A)a place where a restriction enzyme cuts DNA
B)a chart that traces the family history of a genetic trait
C)a particular nucleotide sequence at a particular locus whose inheritance can be followed
D)a radioactive probe used to find a gene
E)an enzyme used to cut DNA
C
Human nerve cells differ from human muscle cells because different sets of genes are expressed; in each type of cell, different genes are transcribed into mRNA and translated into protein. Which of the following techniques would be the most efficient way to identify the genes that these cells express? ( Concept 20.4)
A)gel electrophoresis of DNA fragments
B)DNA microarray assays
C)isolating and analyzing all the proteins from each type of tissue
D)PCR
E)chromosome walking
B
Gene therapy involves _____. ( Concept 20.4)
A)adding a functioning version of a defective gene to the cells of an individual
B)allowing individuals to follow the natural progression of a genetic disorder, accompanied by psychological counseling, then drug treatment when the condition becomes life-threatening
C)no serious ethical questions
D)replacing organs affected with genetic disorders by transplants
E)All of the listed responses are correct.
A
A molecular biologist used a retroviral vector to introduce a gene coding for a certain human enzyme into mouse cells. One cell line was isolated that was able to make the human enzyme, but it had lost the ability to express an endogenous, normally expressed gene in the process. What is the best explanation for these results? ( Concept 20.4)
A)The virus caused the mouse cells to become diseased.
B)The virus had transferred a gene from one mouse cell to another.
C)The virus inserted the gene encoding the human enzyme within the sequence of a normally expressed endogenous gene.
D)The virus was too small to carry the entire gene.
E)The enzyme acted as a nuclease enzyme, cutting up mouse DNA.
C
DNA fingerprints are used to determine whether Sam could be the father of Becky's baby. Sam is not the father if _____ genetic fingerprint shows some bands not present in _____ genetic fingerprint. ( Concept 20.4)
A)Sam's ... the baby's
B)Becky's ... the baby's
C)the baby's ... Sam's
D)the baby's ... Becky's
E)the baby's ... Sam's or Becky's
E
DNA fingerprints used as evidence in a murder trial look something like supermarket bar codes. The pattern of bars in a DNA fingerprint shows _____. ( Concept 20.4)
A)the order of bases in a particular gene
B)the presence of various-sized fragments of DNA
C)the presence of dominant or recessive alleles for particular traits
D)the order of genes along particular chromosomes
E)the exact location of a specific gene in a genomic library
B
Which of the following would be considered a transgenic organism? ( Concept 20.4)
A)a bacterium that has been treated with a compound that affects the expression of many of its genes
B)a human treated with insulin produced by E. coli bacteria
C)a fern grown in cell culture from a single fern root cell
D)a rat with rabbit hemoglobin genes
E)All of the listed responses are correct.
D
Transgenic organisms can be scientifically or commercially useful only if _____. ( Concept 20.4)
A)the inserted ("foreign") gene is drawn from the human genome
B)the inserted ("foreign") gene is expressed in the host organism
C)the host organism is a microorganism
D)the vector is a plasmid
E)All of the listed responses are correct.
B
In genetic engineering, the highly active plasmid from Agrobacterium tumefaciens is used to _____. ( Concept 20.4)
A)insert genes of interest into plant chromosomes
B)cut DNA at a specific base sequence
C)locate specific genes on animal chromosomes
D)detect and correct mistakes in DNA replication
E)All of the listed responses are correct.
A