Deck 10: Recombinant DNA Technology

Question 1

Which of the following techniques is best suited to study protein interactions?

A)PCR
B)The yeast two-hybrid system
C)Restriction mapping
D)RT-PCR
E)Southern blotting

Answer 1

B

Question 2

RFLPs arise due to

A)changes in the number of tandem repeats.
B)base changes that add or delete restriction enzyme recognition sites.
C)addition or deletion of bases between restriction enzyme recognition sites.
D)B and C only
E)All of these

Answer 2

D

Question 3

Successful cotransformation in the yeast two-hybrid system will result in the binding of proteins produced by each yeast expression vector.These fusion proteins function by

A)binding to the lacZ operator,preventing transcription.
B)binding to RNA polymerase,preventing transcription.
C)binding to the lacZ repressor,enabling transcription.
D)binding to the lacZ upstream activator sequence,enabling transcription.
E)changing color in the presence of X-gal.

Answer 3

D

Question 4

Which of the following is used to screen newborns for the genetic disease PKU?

A)RFLPs
B)ASOs
C)Antibodies
D)PCR
E)All of these

Question 5

RT-PCR is a PCR technique used in amplifying DNA copies of mRNA.

Question 6

A(n)________ is a photograph using X-ray film that is used to identify the position of radiolabeled molecules on a gel.

A)Southern blot
B)northern blot
C)X-rayogram
D)autoradiogram
E)radiocopy

Question 7

Expressed sequence tags,or ESTs,

A)are genetic markers generated from cDNA.
B)pertain to expressed genes only.
C)are oligonucleotides derived from mRNA.
D)A and C only
E)All of these

Question 8

________ blots are used to study DNA fragments,while ________ blots are used to study RNA fragments.

A)Western,northern
B)Southern,western
C)Eastern,northern
D)Southern,northern
E)Western,Southern

Question 9

Somatic cell gene therapy can result in a cure for a genetic disease in an individual as well as any progeny produced by the individual.

Question 10

________ were the first class of DNA sequence polymorphisms discovered in the human genome.

A)SNPs
B)Microsatellites
C)VNTRs
D)STRs
E)RFLPs

Question 11

Which of the following sequences is considered an STR?

A)CGTATTATGC
B)TACGTACGTACG
C)CAGCAGCAG
D)TATTACGCCG
E)A and B only

Question 12

In yeast,expression of the GAL genes is induced when there is ________ in the culture medium.

A)glucose
B)lactose
C)galactose
D)maltose
E)Any of these

Question 13

ASO probes are used for the molecular testing of

A)chromosomal rearrangements.
B)single nucleotide changes in a DNA region.
C)RFLP fragments in a DNA region.
D)defective proteins implicated in disease.
E)successfully cloned Ti plasmids.

Question 14

When yeast cells are cultured in the presence of both glucose and galactose,the GAL genes are

A)transcribed and then translated.
B)transcribed but not translated.
C)neither transcribed nor translated.
D)translated but not transcribed.
E)transcribed and translated simultaneously.

Question 15

For the yeast galactose metabolizing gene,GAL1,to be transcribed,the regulatory protein produced by the GAL4 gene binds to

A)RNA polymerase.
B)upstream activator sequence G (UAS_G)region.
C)a ribosome.
D)the operator sequence.
E)the repressor protein.

Question 16

Vectors capable of entering two or more different host organisms are known as

A)dual vectors.
B)omnivectors.
C)shuttle vectors.
D)parity vectors.
E)universal vectors.

Question 17

DNA markers are DNA polymorphisms that are useful for genetic mapping.

Question 18

In a sequenced genome,candidate protein-encoding genes are identified by searching for

A)STRs.
B)RFLPs.
C)ESTs.
D)SNPs.
E)ORFs.

Question 19

The Guthrie test is used to screen all newborns in the United States for cystic fibrosis.

Question 20

A couple with STR genotypes (50,75)and (50,100)(where the allele numbers denote repeat length)have several children.What are the possible genotypes of their children for this STR locus?

Question 21

Molecular DNA testing is used to test for aneuploids.

Question 22

A potentially serious problem with Taq polymerase in PCR is its lack of proofreading ability.Briefly explain why this can be a problem and at which stages during the PCR process this is most and least problematic.

Question 23

Two STR loci were determined to have the following allele frequencies in the general population:
STR A STR B
Alleles: 1A: 0.1 1B: 0.4
2A: 0.55 2B: 0.4
3A: 0.25 3B: 0.2
4A: 0.1
A suspect in a criminal trial was genetically tested for these loci and was found to have the genotype (1A,1A)for STR A and (2B,2B)for STR B-homozygous for both loci.What is the probability that a randomly sampled person from this population would also have this genotype?

Question 24

Briefly list the basic steps involved in constructing a DNA fingerprint for a paternity case.

Question 25

How do genetic tests differ from diagnostic tests for genetic disease?

Question 26

How does a transcribable vector differ from an expression vector?

Question 27

Rapid detection of SNPs,which are allelic variants,can be accomplished with DNA microarrays.If a microarray is set up for a set of genes,including all variants,outline a general procedure for quickly assaying the genotype of multiple individuals for that set of genes.

Question 28

The Ti plasmid is a natural plasmid in the soil bacterium Agrobacterium tumefaciens.

Question 29

Genetic testing is typically done with blood samples,yet red blood cells (erythrocytes)are anucleate (lack nuclei)and are thus devoid of DNA.How,then,are these tests done?

Question 30

Antisense mRNA can be used to regulate the expression of genes.Briefly describe how this technology was used to slow the ripening of Calgene's ill-fated Flavr-Savr^TM tomato.

Question 31

Humulin is insulin created by recombinant DNA technology.

Question 32

Ti plasmids and the T-DNA system can be used to transform any vascular plant.

Question 33

DNase is used to treat hemophilia.

Question 34

Study of P elements in Drosophila has shown that gene regulation can be accomplished by differential mRNA transcript processing.Explain.

Question 35

How does an RFLP help identify sickle-cell anemia?

Question 36

DNA fingerprinting can be used to convict criminals,but has had little application in exonerating individuals already convicted.

Question 37

PCR has revolutionized the criminal justice system through DNA fingerprinting.For a given fragment of DNA,showing that a suspect's fingerprint differs from that found at a crime scene immediately excludes him or her from suspicion,yet finding a match does not mean that guilt can be automatically concluded.Why?

Question 38

Briefly explain how Ti plasmids induce crown gall (tumor)growth in plants parasitized by Agrobacterium tumefaciens,highlighting the specific properties that make this plasmid so useful in biotechnology.

Question 39

DNA sequencing using the dideoxy sequencing method involves PCR reactions using Taq polymerase,which we learned in this chapter can introduce errors because it lacks a proofreading mechanism.What precaution(s)can be taken in genomic or other sequencing projects to minimize the possibility of producing DNA sequences with errors?

Question 40

How has the Bt protein been used to increase insect-resistance in plants?