In order to identify a specific restriction fragment using a probe, what must be done?

In order to identify a specific restriction fragment using a probe, what must be done? 

A) The fragments must be separated by electrophoresis.
B) The fragments must be treated with heat or chemicals to separate the strands of the double helix.
C) The probe must be hybridized with the fragment.
D) The fragments must be separated by electrophoresis and the fragments must be treated with heat or chemicals to separate the strands of the double helix.
E) The fragments must be separated by electrophoresis, the fragments must be treated with heat or chemicals to separate the strands of the double helix, and the probe must be hybridized with the fragment.






Answer: E

Why might a laboratory be using dideoxy nucleotides?

Why might a laboratory be using dideoxy nucleotides? 

A) to separate DNA fragments
B) to clone the breakpoints of cut DNA
C) to produce cDNA from mRNA
D) to sequence a DNA fragment
E) to visualize DNA expression






Answer: D

The reason for using Taq polymerase for PCR is that

The reason for using Taq polymerase for PCR is that 

A) it is heat stable and can withstand the temperature changes of the cycler.
B) only minute amounts are needed for each cycle of PCR.
C) it binds more readily than other polymerases to primer.
D) it has regions that are complementary to primers.
E) All of these are correct.





Answer: A

Why are BACs preferred today rather than bacteriophages for making genomic libraries?

Why are BACs preferred today rather than bacteriophages for making genomic libraries?

A) The BAC carries more DNA.
B) The BAC can carry entire genes and their regulatory elements.
C) Larger BACs are easier to store.
D) The BAC can carry entire genes and their regulatory elements, and larger BACs are easier to store.
E) The BAC carries more DNA, the BAC can carry entire genes and their regulatory elements, and larger BACs are easier to store.






Answer: E

Pax-6 is a gene that is involved in eye formation in many invertebrates, such as Drosophila. Pax-6 is found as well in vertebrates. A Pax-6 gene from a mouse can be expressed in a fly and the protein (PAX-6) leads to a compound fly eye. This information suggests which of the following?

Pax-6 is a gene that is involved in eye formation in many invertebrates, such as Drosophila. Pax-6 is found as well in vertebrates. A Pax-6 gene from a mouse can be expressed in a fly and the protein (PAX-6) leads to a compound fly eye. This information suggests which of the following? 

A) Pax-6 genes are identical in nucleotide sequence.
B) PAX-6 proteins have identical amino acid sequences.
C) Pax-6 is highly conserved and shows shared evolutionary ancestry.
D) PAX-6 proteins are different for formation of different kinds of eyes.
E) PAX-6 from a mouse can function in a fly, but a fly's Pax-6 gene cannot function in a mouse.






Answer: C

Why is it so important to be able to amplify DNA fragments when studying genes?

Why is it so important to be able to amplify DNA fragments when studying genes? 

A) DNA fragments are too small to use individually.
B) A gene may represent only a millionth of the cell's DNA.
C) Restriction enzymes cut DNA into fragments that are too small.
D) A clone requires multiple copies of each gene per clone.
E) It is important to have multiple copies of DNA in the case of laboratory error.






Answer: B

Which of the following is used to make complementary DNA (cDNA) from RNA?

Which of the following is used to make complementary DNA (cDNA) from RNA? 

A) restriction enzymes
B) gene cloning
C) DNA ligase
D) gel electrophoresis
E) reverse transcriptase




Answer: E

The major advantage of using artificial chromosomes such as YACs and BACs for cloning genes is that

The major advantage of using artificial chromosomes such as YACs and BACs for cloning genes is that

A) plasmids are unable to replicate in cells.
B) only one copy of a plasmid can be present in any given cell, whereas many copies of a YAC or BAC can coexist in a single cell.
C) YACs and BACs can carry much larger DNA fragments than ordinary plasmids can.
D) YACs and BACs can be used to express proteins encoded by inserted genes, but plasmids cannot.
E) All of these are correct.






Answer: C

To introduce a particular piece of DNA into an animal cell, such as that of a mouse, you would find more probable success with which of the following methods?

To introduce a particular piece of DNA into an animal cell, such as that of a mouse, you would find more probable success with which of the following methods?

A) the shotgun approach
B) electroporation followed by recombination
C) introducing a plasmid into the cell
D) infecting the mouse cell with a Ti plasmid
E) transcription and translation






Answer: B

Sequencing an entire genome, such as that of C. elegans, a nematode, is most important because

Sequencing an entire genome, such as that of C. elegans, a nematode, is most important because

A) it allows researchers to use the sequence to build a "better" nematode, which is resistant to disease.
B) it allows research on a group of organisms we do not usually care much about.
C) the nematode is a good animal model for trying out cures for viral illness.
D) a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates.
E) a sequence that is found to have no introns in the nematode genome is likely to have acquired the introns from higher organisms.








Answer: D

A student wishes to clone a sequence of DNA of ~200 kb. Which vector would be appropriate?

A student wishes to clone a sequence of DNA of ~200 kb. Which vector would be appropriate? 

A) a plasmid
B) a typical bacteriophage
C) a BAC
D) a plant virus
E) a large polypeptide






Answer: C

A researcher needs to clone a sequence of part of a eukaryotic genome in order to express the sequence and to modify the polypeptide product. She would be able to satisfy these requirements by using which of the following vectors?

A researcher needs to clone a sequence of part of a eukaryotic genome in order to express the sequence and to modify the polypeptide product. She would be able to satisfy these requirements by using which of the following vectors? 

A) a bacterial plasmid
B) BAC to accommodate the size of the sequence
C) a modified bacteriophage
D) a human chromosome
E) a YAC with appropriate cellular enzymes






Answer: E

Which of the following best describes the complete sequence of steps occurring during every cycle of PCR? 1. The primers hybridize to the target DNA. 2. The mixture is heated to a high temperature to denature the double-stranded target DNA. 3. Fresh DNA polymerase is added. 4. DNA polymerase extends the primers to make a copy of the target DNA.

Which of the following best describes the complete sequence of steps occurring during every cycle of PCR?
1. The primers hybridize to the target DNA.
2. The mixture is heated to a high temperature to denature the double-stranded target DNA.
3. Fresh DNA polymerase is added.
4. DNA polymerase extends the primers to make a copy of the target DNA. 

A) 2, 1, 4
B) 1, 3, 2, 4
C) 3, 4, 1, 2
D) 3, 4, 2
E) 2, 3, 4






Answer: A

Yeast artificial chromosomes contain which of the following elements?

Yeast artificial chromosomes contain which of the following elements? 

A) centromeres only
B) telomeres only
C) origin of replication only
D) centromeres and telomeres only
E) centromeres, telomeres, and an origin of replication






Answer: E

The DNA fragments making up a genomic library are generally contained in

The DNA fragments making up a genomic library are generally contained in 

A) BACs.
B) recombinant viral RNA.
C) individual wells.
D) DNA-RNA hybrids.
E) radioactive eukaryotic cells.




Answer: A

Why are yeast cells frequently used as hosts for cloning?

Why are yeast cells frequently used as hosts for cloning? 

A) They easily form colonies.
B) They can remove exons from mRNA.
C) They do not have plasmids.
D) They are eukaryotic cells.
E) Only yeast cells allow the gene to be cloned.






Answer: D

A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using

A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using 

A) RNA polymerase to transcribe the gene.
B) a restriction enzyme to cut the gene into shorter pieces.
C) reverse transcriptase to reconstruct the gene from its mRNA.
D) DNA polymerase to reconstruct the gene from its polypeptide product.
E) DNA ligase to put together fragments of the DNA that code for a particular polypeptide.






Answer: C

A principal problem with inserting an unmodified mammalian gene into a BAC, and then getting that gene expressed in bacteria, is that

A principal problem with inserting an unmodified mammalian gene into a BAC, and then getting that gene expressed in bacteria, is that 

A) prokaryotes use a different genetic code from that of eukaryotes.
B) bacteria translate polycistronic messages only.
C) bacteria cannot remove eukaryotic introns.
D) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA.
E) bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible with mammalian DNA.






Answer: C

What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform bacteria with a recombinant DNA molecule. II. Cut the plasmid DNA using restriction enzymes. III. Extract plasmid DNA from bacterial cells. IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. V. Use ligase to seal plasmid DNA to nonplasmid DNA.

What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium?
I. Transform bacteria with a recombinant DNA molecule.
II. Cut the plasmid DNA using restriction enzymes.
III. Extract plasmid DNA from bacterial cells.
IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments.
V. Use ligase to seal plasmid DNA to nonplasmid DNA. 

A) I, II, IV, III, V
B) II, III, V, IV, I
C) III, II, IV, V, I
D) III, IV, V, I, II
E) IV, V, I, II, III





Answer: C

How does a bacterial cell protect its own DNA from restriction enzymes?

How does a bacterial cell protect its own DNA from restriction enzymes? 

A) by adding methyl groups to adenines and cytosines
B) by using DNA ligase to seal the bacterial DNA into a closed circle
C) by adding histones to protect the double-stranded DNA
D) by forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching
E) by reinforcing the bacterial DNA structure with covalent phosphodiester bonds





Answer: A