Ch.9
To allow primers to bind to the DNA template strands
After the 94∘C step, why must the thermocycler reduce the temperature to 55∘C? To allow primers to bind to the DNA template strands To allow the DNA template strands to bind to each other To separate the DNA template strands To optimize DNA polymerase activity
Insects that normally destroy non-toxin-producing crops will be killed when they eat plants that do produce the toxin.
Bt crops are engineered in the lab to produce Bt toxins due to the presence of a bacterial gene from B. thuringiensis. Why is it advantageous for the plants to produce the Bt toxin? The Bt toxin will protect the plant from pathogenic bacteria. The plant will release chemicals that will repel all nearby insects. People who eat the food produced by a Bt crop will be resistant to bacterial infections. Insects that normally destroy non-toxin-producing crops will be killed when they eat plants that do produce the toxin.
Genetically engineered crops have an advantageous gene from another organism inserted into their genome.
Bt crops, including potatoes and cotton, are genetically engineered using laboratory techniques. Which of the following utilizes recombinant DNA technology to produce advantageous traits in the crops that are produced? Genetically engineered crops have natural characteristics that give them a genetic advantage. Genetically engineered crops have a genetic advantage because the parent strains have advantageous traits. Genetically engineered crops have an advantageous gene from another organism inserted into their genome. Genetically engineered crops naturally produce larger plants and bountiful products.
electroporation
Foreign DNA can be inserted into cells using a variety of different methods. Which method involves the formation of microscopic pores in the cell's membrane? transformation heat shock electroporation protoplast fusion
The Bt gene could ultimately make the plants pathogenic to humans. The Bt toxin could negatively affect the taste of the food that is produced from these crops. The Bt toxin could result in the death of non-pest species of insects.
GM crops have raised issues among communities in which they are produced. Which of the following are concerns raised by the public about genetically engineered crops? Select all that apply. The Bt gene could ultimately make the plants pathogenic to humans. Genetically engineered crops could harm the economy. The Bt toxin could negatively affect the taste of the food that is produced from these crops. The Bt toxin could result in the death of non-pest species of insects.
They cut DNA at sites, called recognition sites, that have specific nucleotide sequences.
How do restriction enzymes cut DNA sequences? They cut DNA at sequences that have lots of adenine bases. They cut DNA at sites, called recognition sites, that have specific nucleotide sequences. They have the ability to cut DNA randomly.
The high heat of the denaturation step breaks the hydrogen bonds between the two strands.
How do the strands separate during PCR? The cycling of the temperatures breaks the hydrogen bonds between the two strands. The DNA polymerase breaks the hydrogen bonds between the two strands. The high heat of the denaturation step breaks the hydrogen bonds between the two strands. The primers separate the strands during the annealing step.
after exposure to 94∘C
In PCR, it is important to use Taq DNA polymerase, as opposed to other DNA polymerases. This is because Taq is capable of synthesizing DNA _________. at 94∘C from user-provided DNA and primers after exposure to 94∘C at 55∘C
To insert a desirable gene, remove an undesirable gene, or replace a defective gene with a functioning gene
In general, how might recombinant DNA technology be used to prevent a genetic disorder caused by a mutation in a single gene? To insert a desirable gene, remove an undesirable gene, or replace a defective gene with a functioning gene To insert a desirable gene To replace a defective gene with a working gene To remove an undesirable gene
5' to 3'
In which direction does DNA polymerase synthesize the new DNA strand? 3' to 5' 5' to 3' Both 5' to 3' and 3' to 5'
polymerase chain reaction.
PCR stands for polymerization copying rapidly. polymerase chain reaction. polymerase copy reaction.
Producing a clone generates many copies of the gene of interest.
Recombinant DNA techniques typically involve generating a clone. Why? A clone is generated when a cell takes up the vector. Recombining the clone produces the recombinant DNA. Producing a clone generates many copies of the gene of interest. A clone is used to get the gene of interest into a suitable cell.
Amplify the gene using PCR. Insert the gene into a plasmid vector. Transform the vector into the bacteria.
Scientists like to use fluorescent proteins for various types of recombinant DNA procedures. You have a very small amount of the gene for a fluorescent protein. You'd like to make a fluorescent bacterium. Which of the following represents the correct sequence of procedures that you would use? Amplify the gene using PCR. Transform the vector into the bacteria. Insert the gene into a plasmid vector. Insert the gene into a plasmid vector. Amplify the gene using PCR. Transform the vector into the bacteria. Transform the vector into the bacteria. Amplify the gene using PCR. Insert the gene into a plasmid vector. Amplify the gene using PCR. Insert the gene into a plasmid vector. Transform the vector into the bacteria.
DNA polymerase would synthesize DNA more slowly.
Suppose the thermocycler is INCORRECTLY programmed to omit the 72∘C step in each cycle of an otherwise normal PCR run. Which of the following would most likely occur? DNA template strands would bind to each other. DNA polymerase would synthesize DNA more slowly. Primers would NOT bind to DNA template strands. DNA polymerase would be active at 94∘C.
Subjects samples to temperature changes
What does a thermocycler do? Monitors the synthesis of DNA Subjects samples to temperature changes Purifies DNA from a crude sample Adds reagents to facilitate the PCR run
The machine that controls the heat of the reaction, cycling between the different temperatures of the different steps during PCR
What is a thermocycler? The process of cycling through the different temperatures of a PCR reaction 30 times The machine that controls the heat of the reaction, cycling between the different temperatures of the different steps during PCR The name for the DNA primers used in a PCR reaction The special DNA polymerase, used in a PCR reaction, that can tolerate the high temperatures
To quickly increase the number of copies of a specific DNA sequence
What is the end goal of PCR? To quickly increase the number of copies of a specific DNA sequence To allow cells to make DNA faster, thereby growing faster To increase the pool of different DNA sequences
They provide a 3' end for the DNA polymerase.
What is the function of the primers in PCR? They polymerize free nucleotides to form the new DNA strands. They provide a 3' end for the DNA polymerase. They provide energy for the DNA polymerization reactions. They are the monomer building blocks from which the DNA strand is synthesized.
94 °C, 60 °C, 72 °C
What is the sequence of the temperatures of a typical PCR reaction? 72 °C, 94 °C, 60 °C 94 °C, 60 °C, 72 °C 94 °C, 72 °C, 60 °C 60 °C, 72 °C, 94 °C 72 °C, 60 °C, 94 °C
72 °C
What is the temperature used for the extension step? 94 °C 60 °C 72 °C
Deoxyribonucleoside triphosphates
What provides the energy for DNA polymerization in a PCR reaction? Primers Deoxyribonucleoside triphosphates DNA polymerase Template DNA
metagenomics
Which of the following applications of recombinant DNA technology is NOT controversial? biological weapons development genetic food modification genetic screening metagenomics
DNA ligase
Which of the following attaches the target gene to a desired location? DNA ligase Restriction enzymes Plasmids Chromosomal DNA
a culture of genetically identical cells
Which of the following best describes a clone in the context of genetic modification procedures? an identical copy of the gene of interest a culture of genetically identical cells a vector, once it contains a copy of the gene of interest a cell that is genetically identical to its parent
Bacteria now produce hGH.
Which of the following best describes how recombinant DNA technology currently helps patients who do NOT produce adequate amounts of growth hormone (hGH)—a condition that otherwise leads to stunted growth? Recombinant vectors are used to stimulate hGH production in these patients. Bacteria now produce rDNA coding for hGH. Bacteria now produce hGH. Recombinant vectors now produce hGH.
To provide a structure from which DNA can be synthesized
Which of the following best describes the purpose of primers in PCR? To activate DNA polymerase to replicate DNA To provide a structure from which DNA can be synthesized To separate double-stranded DNA into single strands To provide a template for free nucleotides
Each cycle of PCR doubles the amount of DNA synthesized, but the number of copies starts out small. Numerous cycles are required to produce a sufficient number of copies.
Which of the following best describes why PCR protocols contain numerous cycles of the denaturation/annealing/extension steps? Each cycle of PCR incorporates some of the included primers into amplicons. Numerous cycles of PCR are required to ensure all primers are incorporated. Each cycle of PCR allows Taq polymerase to partially synthesize the target sequence. Numerous cycles are necessary for the target sequence to be fully copied. Each cycle of PCR doubles the amount of DNA synthesized, but the number of copies starts out small. Numerous cycles are required to produce a sufficient number of copies. The denaturation step of each cycle only separates some of the source DNA. By performing numerous cycles, PCR generates copies of all the target sequences.
Cells usually won't copy an isolated gene sequence.
Which of the following best describes why a vector is used in genetic modification procedures? The vector ensures that the clone remains pure. Cells usually won't copy an isolated gene sequence. The clone must be able to produce proteins from the rDNA containing the gene of interest. The gene of interest must be isolated from adjacent genes.
The Bt toxin gene is isolated and inserted into a Ti plasmid from Agrobacterium tumefaciens. The engineered Ti plasmid is taken up by a bacterium that infects the cotton plant.
Which of the following best explains how scientists are able to introduce the bacterial gene for Bt toxin into the cotton plant genome? The bacterial gene for Bt toxin is isolated, and the DNA is put into tiny bullets (like BB's) that are "shot" into the cotton plant using a gene gun. The Bt toxin gene is isolated and inserted into a Ti plasmid from Agrobacterium tumefaciens. The engineered Ti plasmid is taken up by a bacterium that infects the cotton plant. A virus is engineered to contain the Bt toxin gene. This virus is then used to infect the plant and pass on the gene. The Bt toxin gene is added to water that is sprayed on the cotton plants. The gene is taken up through the roots of the plant.
They always contain only one gene.
Which of the following is NOT a property of useful vectors? They must be small enough to allow them to be manipulated prior to injection. They always contain only one gene. They must be able to self-replicate. They must have properties that allow their survival in the host cell.
Sequencing a gene, diagnosing a disease, and providing enough DNA for cloning into another organism
Which of the following is an application that uses PCR? Sequencing a gene Diagnosing a disease Providing enough DNA for cloning into another organism Sequencing a gene, diagnosing a disease, and providing enough DNA for cloning into another organism
DNA fingerprinting
Which of the following methods could be used to identify the source of an outbreak? reverse genetics artificial selection DNA fingerprinting production of a recombinant protein
gene silencing: production of subunit vaccines
Which of the following pairings of recombinant DNA techniques and applications does NOT match? gene therapy: replacing a defective gene PCR: making many copies of a segment of DNA genetic modification of yeast: production of purified insulin gene silencing: production of subunit vaccines
It has limited application because genes of interest cannot be moved from one type of cell to another.
Which of the following statements about recombinant DNA technology is FALSE? It can be used to screen individuals for many different types of genetic diseases. It allows researchers to make many copies of a gene of interest. It has limited application because genes of interest cannot be moved from one type of cell to another. It allows researchers to make protein products of a gene.
They are important for cloning applications because they can be used to cut DNA at specific nucleotide sequences.
Which statement best describes restriction enzymes? They are necessary for the polymerase chain reaction (PCR) to occur. They can cut only circular plasmid DNA. They are important for cloning applications because they can be used to cut DNA at specific nucleotide sequences. They randomly cut DNA molecules to generate numerous fragments.
It can withstand the high temperatures associated with PCR.
Why is DNA polymerase from Thermus aquaticus ideal for PCR? It does not require energy to polymerize DNA. It can synthesize DNA 5' to 3' and 3' to 5'. It does not require primers. It can withstand the high temperatures associated with PCR.
PCR creates large amounts of DNA from minute source quantities.
Why is PCR a valuable technique? PCR creates large amounts of DNA from minute source quantities. PCR harvests small quantities of DNA. PCR stimulates transcription of genes (DNA). PCR separates DNA from crude mixtures of other biomolecules.
It can be copied, transcribed, and translated into a desired protein.
Why would a recombinant DNA molecule be inserted into a host cell? Plasmids cannot be isolated outside of a host cell. It can protect the recombinant DNA. Restriction enzymes can only be used inside of a cell. It can be copied, transcribed, and translated into a desired protein.