Chapter 10 DNA Plant Biotech and Genomics Verified Test Bank

Chapter 10: Recombinant DNA Technology, Plant Biotechnology, and Genomics

Multiple-Choice Questions

Traditional breeding programs:

a. involve inserting a plasmid into a host cell.

b. involve infecting a host plant with a virus.

c. allow gene transfers between species incapable of hybridizing.

d. depend on inherent genetic variability.

e. allow the precise insertion of genes into a plant.

Genetically modified plants were first grown commercially in:

a. 1965.

b. 1985.

c. 1996.

d. 2001.

e. 2009.

Which of the following statements concerning restriction enzymes is FALSE?

a. They are a type of endonuclease.

b. They recognize DNA sequences typically four to six nucleotides long.

c. They recognize single-stranded DNA sequences.

d. Some make straight cuts in the DNA.

e. They recognize specific palindromic sequences.

A sticky-ended fragment can join with another DNA segment only if that segment:

a. has been cut with the same restriction enzyme.

b. has been cut with the same ligase.

c. is palindromic.

d. is part of a plasmid.

e. is part of a virus.

DNA ligase would most likely be used in recombinant DNA technology to:

a. function as a vector.

b. screen for recombinant plasmids.

c. stimulate a transformed cell to divide.

d. cut DNA into fragments with sticky ends.

e. join DNA fragments together.

Which of the following statements concerning vectors is FALSE?

a. Vectors are used to transform cells.

b. Vectors function as DNA carriers.

c. A virus can be a vector.

d. A plasmid can be a vector.

e. A host cell can be a vector.

By definition, a transformed cell:

a. contains a plasmid.

b. contains a recombinant DNA molecule.

c. contains a virus.

d. functions as a vector.

e. divides in such a way so as to amplify the DNA fragment.

The amp^R gene is used in recombinant DNA technology to:

a. produce β-galactosidase.

b. clone a particular gene fragment.

c. screen for the presence of cells containing recombinant plasmids.

d. help the bacterium to survive on a medium containing lactose.

e. transform a bacterial cell.

Suppose a plasmid containing a gene of interest plus the amp^R gene is used to transform E. coli cells. When these cells are placed on a medium containing ampicillin, what will happen?

a. They will die.

b. They will survive and grow.

c. They will form blue colonies.

d. They will glow with a green color.

e. They will glow when provided with luciferin plus ATP.

An example of a selectable marker gene is:

a. the gene for a green fluorescent protein.

b. the luciferase gene.

c. EcoRI.

d. lacZ.

e. amp^R.

When the lacZ gene technique is used to detect recombinant DNA in host bacterial cells, the colonies will appear _______ if the cells have been successfully transformed.

a. red

b. white

c. blue

d. green

e. fluorescent

Which of the following would be linked to a promoter to determine if a particular gene introduced into a host cell is directing the synthesis of protein?

a. amp^R

b. lacZ

c. X-gal

d. EcoRI

e. the luciferase gene

Which of the following statements concerning DNA libraries is FALSE?

a. A genomic library is obtained by cutting the entire genome of an organism.

b. A cDNA library is obtained by using reverse transcriptase.

c. A DNA library contains cloned fragments of most of an organism’s genome.

d. A cDNA library lacks introns.

e. A genomic library lacks exons.

In recombinant DNA technology, reverse transcriptase is used to:

a. synthesize cDNA.

b. synthesize mRNA.

c. cut DNA into fragments.

d. amplify a specific gene.

e. transfer a plasmid into a cell.

The polymerase chain reaction is used to:

a. determine where gene promoters are active.

b. produce millions of copies of a DNA segment in a short time.

c. determine if a gene inserted into a cell is active or inactive.

d. produce a cDNA library.

e. transform a cell.

The Taq polymerase is used in recombinant DNA technology to:

a. locate specific DNA segments.

b. determine the nucleotide sequence of a specific gene.

c. make up to a millionfold copies of a DNA segment in a few hours.

d. make cDNA.

e. carry out “shotgun cloning.”

One important characteristic the Taq polymerase is its

a. insensitivity to pH.

b. ability to glow when in the presence of a suitable substrate.

c. ability to be cloned.

d. resistance to high temperature.

e. ability to transform cells.

In recombinant DNA technology, cutting different samples of a single DNA molecule with different restriction enzymes allows one to:

a. amplify the DNA molecule.

b. carry out DNA hybridization.

c. locate a gene of interest.

d. determine the function of a gene.

e. determine the nucleotide sequence of a gene.

The first eukaryotic genome to be sequenced was that of:

a. Haemophilus influenzae.

b. Saccharomyces cerevisae.

c. Arabidopsis thaliana.

d. Agrobacterium tumefaciens.

e. Caenorhabditis elegans.

By definition, hydroponics is the technique for growing:

a. shoot tips.

b. isolated leaf pieces.

c. isolated roots

d. plant embryos.

e. plants without soil.

It was not until the discovery of ________ that organ and tissue culture became feasible.

a. hydroponics

b. plant hormones

c. the importance of sucrose in nutrient solutions

d. the essential mineral elements

e. biotechnology

Because meristems lack _________ tissues, meristem culture results in plants that lack _________.

a. vascular; viruses

b. vascular; fungi

c. epidermal; viruses

d. epidermal; fungi

e. epidermal; insect eggs

Crown-gall tumors are produced by a(n):

a. virus.

b. bacterium.

c. fungus.

d. alga.

e. plant.

Agrobacterium induces the formation of crown-gall tumors by transferring the ____ plasmid containing ______ to the host plant’s nuclear DNA.

a. CG; CG-DNA

b. O; R-DNA

c. C; C-DNA

d. Ti; T-DNA

e. T-DNA; Ti

In Agrobacterium, genes that code for enzymes involved in the synthesis of the hormone auxin are found in the _____ region of the plasmid.

a. R

b. O

c. onc

d. vir

e. A

In the Agrobacterium Ti plasmid, the ____ gene codes for the synthesis of amino acids that are used as food.

a. R

b. O

c. onc

d. vir

e. A

In the Ti plasmid of Agrobacterium tumefaciens, the onc region contains genes that code for enzymes in:

a. auxin synthesis only.

b. opine synthesis only.

c. cytokinin synthesis only.

d. auxin and cytokinin synthesis.

e. auxin and opine synthesis.

Opines are:

a. hormones.

b. genes.

c. amino acid derivatives.

d. vitamins.

e. enzymes.

In _________, electrical pulses cause pores in the plasma membrane to open, thus allowing DNA to enter the cell.

a. particle bombardment

b. the polymerase chain reaction

c. a reaction involving reverse transcriptase

d. electrophoresis

e. electroporation

Which of the following statements about particle bombardment is FALSE?

a. It is used to deliver DNA but not RNA into a cell.

b. It involves the use of gold or tungsten beads.

c. It involves high-velocity microprojectiles.

d. It involves the use of a gene gun.

e. It has been used to create a virus-resistant strain of papaya.

The BT gene is transferred for the purpose of:

a. delaying leaf senescence.

b. reducing the proportion of saturated fats.

c. conferring resistance to caterpillars.

d. conferring resistance to herbicides.

e. delaying fruit ripening.

Glyphosate is:

a. an enzyme in amino acid synthesis.

b. a mutant gene from Arabidopsis.

c. toxic to animals.

d. an herbicide that kills all plants

e. a mutant gene from Salmonella.

One advantage of inserting into crop plants a gene that codes for an altered enzyme in aromatic amino acid synthesis is that the plants would:

a. be resistant to BT toxin.

b. be resistant to glyphosphate.

c. be resistant to Bacillus thuringiensis.

d. have an increased starch content.

e. have an increased vitamin A content.

Mutant forms of the ethylene receptor gene from Arabidopsis are inserted into plants for the purpose of:

a. increasing starch content.

b. increasing levels of β-carotene.

c. stimulating fruit ripening.

d. conferring resistance to pesticides.

e. delaying flower wilting.

Why would a gene for cytokinin synthesis be fused to a promoter that is expressed only in senescent leaves?

a. to delay leaf senescence

b. to confer resistance to herbicides

c. to confer resistance to BT toxin

d. to increase starch content

e. to increase glyphosate production

“Golden rice” is notable because of its:

a. high β-carotene content.

b. high starch content.

c. resistance to herbicides.

d. delayed senescence.

e. resistance to insect larvae.

The advantage of using the “ice-minus” strain of Pseudomonas syringae is:

a. reducing susceptibility to fungi.

b. increasing resistance to bacteria that thrive at low temperatures.

c. increasing resistance to herbicides.

d. reducing susceptibility to frost.

e. increasing resistance to insect larvae.

One aspect of structural genomics is:

a. determining the function of genes.

b. determining the function of gene products.

c. preparing physical maps.

d. preparing knockout mutants.

e. comparing evolutionary relationships.

A genetic map is different from a physical map in that a genetic map is:

a. used to determine the function of genes.

b. based on rates of recombination.

c. used to determine which genes are inactivate.

d. based on direct DNA sequencing.

e. based on evolutionary relationships.

Which of the following is NOT one of the goals of functional genomics?

a. identifying the transcriptome

b. identifying the proteome

c. determining the function of genes

d. determining which genes are expressed

e. determining the location of genes on a chromosome

The transcriptome refers to all of the:

a. proteins encoded by the genome.

b. glycoproteins transcribed by the genome.

c. nucleotides present in a cell’s DNA.

d. nucleotides present in a cell’s RNA.

e. RNA molecules transcribed by the genome.

The preparation of knockout mutants involves:

a. inserting a piece of DNA into the gene of interest.

b. the use of closely packed DNA fragments attached to a glass slide.

c. searching for homology.

d. determining the number of base pairs in a gene.

e. determining the rate of recombination.

Which of the following statements about prokaryotic genomes is FALSE?

a. Most consist of a single circular chromosome.

b. Approximately 90% of the identified genes have been assigned a function.

c. About 25% of the genes have no significant similarity to other known genes in bacteria.

d. Horizontal gene exchange periodically occurs.

e. Gene transfers have occurred between bacteria and eukaryotes.

Which of the following statements about eukaryotic genomes is FALSE?

a. They are larger than those of prokaryotes.

b. In general, multicellular eukaryotes have more DNA than unicellular eukaryotes.

c. The greater the complexity of the organism, the more protein-coding genes it has.

d. The roundworm Caenorhacditis has more genes than the fruit fly Drosophila.

e. The plant Arabidopsis has more genes than the fruit fly Drosophila.

True-False Questions

Restriction enzymes cut single-stranded DNA molecules at or near their recognition sequences.

DNA fragments having sticky ends can join with other fragments obtained by using the same restriction enzyme.

Sticky-ended fragments can be joined by specific restriction enzymes.

Cells containing the gene amp^R would not survive when incubated on a medium containing ampicillin.

The polymerase chain reaction is used to quickly make many copies of a DNA segment.

Identical DNA fragments are obtained by cutting the same DNA molecule with different restriction enzymes.

Nowadays, DNA sequencing is rarely done from specific restriction fragments.

Random clones are regularly used to obtain the nucleotide sequences of isolated genes.

When you grow a plant hydroponically, by definition you grow it without its roots in water.

Micropropagation is used to obtain clones of plants.

Totipotency refers to the ability of an individual plant cell to grow into an entire plant.

One advantage of meristem culture is that virus-free plants can be obtained.

Agrobacterium tumefaciens receives the Ti plasmid from its host plant.

The Ti plasmid of Agrobacterium tumefaciens contains genes for plant hormones as well as genes for molecules that nourish the bacterium.

Agrobacterium tumefaciens is used to obtain transgenetic plants.

Electroporation is used to transform monocots because Agrobacterium tumefaciens cannot infect them.

Particle bombardment and electroporation are the two techniques most widely used to transfer DNA into plants.

One of the risks associated with genetic engineering is the spread of genes to weedy relatives by hybridization.

A search for homology would be used to determine the possible function of a gene.

The proteome refers to all the protein molecules transcribed by the DNA.

A knockout mutant has a particular gene inactivated.

Most of the genes in all bacteria are significantly similar.

Horizontal/lateral gene exchange refers to related bacterial species exchanging genetic information over evolutionary time.

In eukaryotes, the more complex the organism the more genes it has.

Essay Questions

1. Recombinant DNA Technology; pp. 193-194; moderate

In what way does recombinant DNA technology involve “recombination”?

2. Recombinant DNA Technology; p. 195; moderate

Explain the difference between a selectable marker gene and a reporter gene.

3. Recombinant DNA Technology; p. 195; moderate

Describe two ways of screening colonies for the presence of transformed cells in recombinant DNA studies.

4. Recombinant DNA Technology; p. 195; moderate

How is a genomic library different from a cDNA library? Compare the procedures for obtaining each of them.

5. Recombinant DNA Technology; pp. 197–198; moderate

Describe how restriction enzymes can be used to obtain the nucleotide sequence of a DNA molecule.

6. Plant Biotechnology; p. 198; moderate

What is meristem culture? Describe one advantage of using it.

7. Plant Biotechnology; pp. 200-201; moderate

Describe how Agrobacterium tumefaciens “is a natural genetic engineer.”

8. Plant Biotechnology; p. 203; moderate

Explain how genetic engineering can be used to confer resistance to 1) insects and 2) herbicides.

9. Plant Biotechnology; p. 205; moderate

Discuss the risks and benefits of introducing genes into crop plants.

10. Genomics; pp. 205–206; moderate

What is meant by “genomics”? Explain the goals of the three subfields of genomics.

11. Genomics; p. 206; moderate

Discuss three techniques used to determine the function of a newly discovered gene.

12. Genomics; pp. 206–207; moderate

Compare and contrast the prokaryotic and eukaryotic genomes.