chapter 9 - mastering microbiology

which of the following attaches the target gene to a desired location?

DNA ligase

suppose the thermocycler is INCORRECTLY programmed to omit the 72C step in each cycle of an other wise normal PCR run. what would most likely occur?

DNA polymerase would synthesize DNA more slowly

Bt crops, including potatoes and cotton, are genetically engineered using lab techniques. which of the following utilizes recombinant DNA technology to produce advantageous traits in the crops that are produced?

genetically engineered crops have an advantageous gene from another organism inserted into their genome - in the case of Bt crops, the gene for a Bacillus thuringiensis - derived toxin (Bt) has been inserted into the plant genome. as a result, the plants produce this toxin as part of their cell's normal protein production. the amount of cotton produced may increase, but not as a result of the insecticide properties of the plans

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?

insects that normally destroy non-toxin-producing crops will be killed when they eat plants that do not produce the toxin - as a result, the insect will starve. this advancement in technology helps protect plants from insects without the use of harsh insecticides that can be harmful to the environment

if you have inserted a gene in the Ti plasmid, the next step in genetic engineering is

inserting the Ti plasmid into Agrobacterium

why would a recombinant DNA molecular be inserted into a host cell?

it can be copied, transcribed, and translated into a desired protein

why is DNA polymerase from Thermus aquaticus ideal for PCR?

it can withstand the high temps associated w PCR

what is an advantage of using E. coli to make a human gene product?

its genes are well known

an advantage of cDNA over genomic DNA is that it

lacks introns

the reaction catalyzed by reverse transcriptase is

mRNA > cDNA

PCR stands for

polymerase chain reaction

the use of "suicide" genes in genetically modified organisms is designed to..

prevent the growth of the modified organisms in then environment

recombinant DNA techniques typically involve generating a clone. why?

producing a clone generates many copies of the gene of interest

what are some applications that use PCR?

sequencing a gene, diagnosing a disease, and providing enough DNA for cloning into another organism

why is baker's yeast useful for expressing genetically engineered genes?

yeast cells are eukaryotic and so would likely be successful in expressing eukaryotic genes

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?

- the Bt toxin could result in the death of non-pest species of insects - 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

which of the following places the steps in the PCR procedure in the correct order? 1. incubate 94C to denature DNA strands 2. incubate at 72C for DNA synthesis 3. incubate at 60C for primer hybridization

1,3,2

sequence of genetic modification procedure

1. isolate bacterial plasmid 2. select gene of interest + inset into plasmid 3. plasmid taken up by bacterium 4. bacteria replicate 5. cloned gene harvested from bacteria

the technique that introduces foreign genes into plants starts with...

1. the Ti plasmid is isolated and prepared for the insertion of foreign DNA 2. the gene for Bt toxin is isolated from the bacterium and inserted into the plasmid 3. the plasmid is taken up by a bacterium 4. the bacterium is used to introduce the Bt toxin gene into the chromosome of plant cells 5. a single plant cell is chosen to produce a plant that now produces Bt toxin

in which direction does DNA polymerase synthesize the new DNA strand?

5' to 3'

match the temperatures in the left column with the appropriate PCR stage on the right 72C, 94C, 55C primer annealing, DNA denaturation, and DNA extension

55C primer annealing 94C DNA denaturation 72C DNA extension

the following steps must be performed to make a bacterium produce human protein X 1- translation 2- restriction enzyme 3- prokaryotic transcription 4- DNA ligase 5- transformation 6- eukaryotic transcription 7- reverse transcription what places the steps in the correct order?

6724531

what is the temp used for the extension step?

72C

you have a small gene that you wish replicated by PCR. after 3 replication cycles, how many double-stranded DNA molecules do you have

8 ( 1- doubles 2 , 2- doubles to 4, 3 - doubles to 8) 1x2 = 2, 2x2 = 4, 4x2 = 8

what is the sequence of the temps of a typical PCR reaction?

94, 60, 72

the following tiles indicate the first five thermocycler steps in a PCR run. arrange them in the correct order

94C for 1 min, 55C for 1 min, 72C for 1 min, 94C for 1 min, 55C for 1 min

which of the following are used by the centers of disease control and prevention to track outbreaks of foodborne disease?

DNA fingerprints, restriction fragment length polymorphisms, and reverse transcriptase PCR (rtPCR)

you want to determine whether a person has a certain mutant gene. the process involves using a primer and a heat-stable DNA polymerase. this process is

PCR

why is PCR a valuable technique?

PCR creates large amounts of DNA from minute source quantities - amplifies specific DNA sequences from minute starting concentrations. thus, PCR is a sensitive technique that can detect the presence of small concentrations of specific DNA. the technique is also useful for creating large quantities of a target DNA sequence for research purposes

what is used to silence specific genes and hold promise for treating cancer or viral disease, such as hepatitis B?

RNA interference (RNAi)

a source of heat-stable DNA polymerase is

Thermus aquaticus

which of the following best describes a clone in the context of genetic modification procedures?

a culture of genetically identical cells

a restriction fragment is

a segment of DNA

in PCR, it is important to use Taq DNA polymerase, as opposed to other DNA polymerases. this is bc Taq is capable of synthesizing DNA ________.

after exposure to 94C - since PCR protocols necessarily include a 94C denaturation step, all of the biomolecules need to remain stable after exposure to this temp. most enzymes are damaged at 94C whereas the Taq polymerase is heat-tolerant and stable

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. what are the correct procedures that you would use

amplify the gene using PCR. insert the gene into a plasmid vector. transform the vector into the bacteria

which of the following methods could be used to identify the source of an outbreak? a. production of recombinant protein b. DNA fingerprinting c. reverse genetics d. artificial selection

b. DNA fingerprinting

which of the following best describes why PCR protocols contain numerous cycles of the denaturation/annealing/extension steps? a. each cycle of PCR incorporates some of the included primers into amplicons. numerous cycles of PCR are required to ensure all primers are incorporated b. 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 c. 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 d. 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

b. 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 statements about recombinant DNA technology is FALSE? a. it can be used to screen individuals for many different types of genetic diseases b. it has limited application bc genes of interest cannot be moved from one type of cell to another c. it allows researchers to make many copies of a gene of interest d. it allows researchers to make protein products of a gene

b. it has limited application bc genes of interest cannot be moved from one type of cell to another - this statement is false. recombinant DNA technology is commonly use to move DNA from one type of cell to another

which of the following is NOT a property of useful vectors? a. they must be able to self-replicate b. they always contain only one gene c. they must be small enough to allow them to be manipulated prior to injection d. they must have properties that allow their survival in the host cell

b. they always contain only one gene

restriction enzymes are

bacterial enzymes that destroy phage DNA

which of the following is NOT a desired characteristic of DNA vectors used in gene cloning procedures? a. circular form of DNA or integrates into the host chromosome b. may replicate in several species c. large size d. self-replication e. has a selectable marker

c. large size

which of the following best describes why a vector is used in genetic modification procedures?

cells usually won't copy an isolated gene sequence

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 a. recombinant vectors now produce hGH b. recombinant vectors are used to stimulate hGH production in these patients c. bacteria now produce rDNA coding for hGH d. bacteria now produce hGH

d. bacteria now produce hGH

which of the following pairings of recombinant DNA techniques and applications does NOT match? a. PCR: making many copies of a segment of DNA b. gene therapy: replacing a defective gene c. genetic modification of yeast: production of purified insulin d. gene silencing: production of subunit vaccines

d. gene silencing: production of subunit vaccines

which statement best describes restriction enzymes? a. they randomly cut DNA molecules to generate numerous fragments b. they can cut only circular plasmid DNA c. they are necessary for the polymerase chain reaction (PCR) to occur d. they are important for cloning applications bc they can be used to cut DNA at specific nucleotide sequences

d. they are important for cloning applications bc they can be used to cut DNA at specific nucleotide sequences

which of the following processes is NOT involved in making cDNA? a. reverse transcription b. RNA processing to remove introns c. transcription d. translation

d. translation

what provides the energy for DNA polymerization in a PCR reaction?

deoxyribonucleoside triphophates

the human genome project, which was completed in 2003, was focused on

determining the nucleotide sequence of the entire human genome

the use of an antibiotic-resistance gene on a plasmid used in genetic engineering makes..

direct selection possible

the restriction enzyme EcoRI recognizes the sequence GAATTC. which of the following is TRUE of DNA after is is treated w EcoRI? a. all of the DNA fragments will have single-stranded regions ending in G b. some of the DNA will have single-stranded regions ending in AA and others will end in G c. all of the DNA will be circular d. all of the DNA will have blunt ends e. all of the DNA fragments will have single-stranded regions ending in AA

e. all of the DNA fragments will have single-stranded regions ending in AA

foreign DNA can be inserted into cells using a variety of different methods. which method involves the formation of microscopic pores in cell's membrane?

electroporation

true/false: the Ti plasmid isolated from Agrobacterium can be used to insert DNA into nay type of plant

false

assume you have discovered a cell that produces a lipase that works in cold water for a laundry additive. you can increase the efficient of this enzyme by changing one amino acid. this is done by

site-directed mutagenesis

what does a thermocycler do?

subjects samples to temperature changes - responsible for adjusting the reaction tube's temperature. by changing the temp of the reaction mixture, the various steps of a PCR cycle are accomplished: DNA denaturation, primer annealing, and DNA extension

which of the following best explains how scientists are able to introduce the bacterial gene for Bt toxin into the cotton plant genome?

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 plants - the toxin acts as a natural insecticide bc insects that ingest it develop digestive issues and ultimately starve to death. this helps to control the insect population that is feeding on the crops w/o the use of harsh chemicals that may interfere with other non-pest populations

PCR can be used to identify an unknown bacterium bc

the RNA primer is specific

how do the strands separate during PCR

the high heat of the denaturation step breaks the hydrogen bonds between the two strands

what is a thermocycler?

the machine that controls the heat of the reaction, cycling bw the different temps of the diff steps during PCR

how do restriction enzymes cut DNA sequences

they cut DNA at sites, called recognition sites, that have specific nucleotide sequences

what is the function of the primers in PCR?

they provide a 3' end for the DNA polymerase

after the 94C step, why must the thermocycler reduce the temp to 55C?

to allow primers to bind to the DNA template strands

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

which of the following best describes the purpose of primers in PCR?

to provide a structure from which DNA can be synthesized

what is the end goal of PCR?

to quickly increase the number of copies of a specific DNA sequence

what method would be used to introduce the plasmid shown in the figure into E. coli?

transformation

true/false: in recombinant DNA technology, a vector is a self-replication segment of DNA, such as a plasmid or viral genome

true

true/false: one of the first commercial successes of recombinant DNA technology was the production of human insulin using genetically engineered E. coli

true

true/false: the Bt toxin derived from Bacillus thuringiensis has been introduced into some crop plants to make them resistant to insect destruction

true

biotechnology involves the

use of microorganisms to make desired products, the use of animal cells to make vaccines, and the development of disease-resistant crop plants

self-replicating DNA used to transmit a gene from one organisms to another is a

vector