destroy foreign DNA
Bacteria use restriction enzymes to _____.
restriction enzyme
An enzyme that cuts DNA at a symmetrical sequence of bases is called a _
the fragments will bond to other fragments with complementary single-stranded ends
When a typical restriction enzyme cuts a DNA molecule, the cuts are staggered so that the DNA fragments have single-stranded ends. This is important in recombinant DNA work because
short bits of single-stranded DNA left at the end of DNA molecules cut by restriction enzymes
In genetic engineering, “sticky ends” refers to _____.
DNA ligase
Which one of the following enzymes could seal a nick in one strand of a double-stranded DNA molecule by creating a sugar-phosphate bond between the adjacent, unjoined nucleotides?
DNA ligase
To create recombinant DNA with long-term stability, it is necessary to have which of the following in the test tube?
a restriction enzyme and a ligase
What two enzymes are needed to produce recombinant DNA?
a plasmid or other agent used to transfer DNA into a living cell
In recombinant methods, the term “vector” refers to _____.
reverse transcriptase, DNA polymerase, restriction enzyme, DNA ligase
Which arrangement of the following four enzymes represents the order in which they would be used in a typical gene-cloning experiment resulting in the insertion of a cDNA into a bacterial plasmid? Begin with the gene’s mRNA transcript.
F factors
A scientist wishing to create an organism capable of breaking down several kinds of toxic waste combines genes from several species of bacteria to create a single “superbacterium.” Which of the following would probably not be needed to do this?
identify genes that have been inserted into bacterial plasmids or separated by electrophoresis
A nucleic acid probe is used to _____.
retroviruses
What is the source of the reverse transcriptase used in recombinant DNA technology?
work backward from mRNA to make a version of the gene without introns
Because eukaryotic genes contain introns, they cannot be translated by bacteria, which lack RNA-splicing machinery. But if you want to engineer a bacterium to produce a eukaryotic protein, you can synthesize a gene without introns. A good way to do this is to _____.
cDNA
DNA synthesized using an RNA template is called _____.
determines which segment of the genome will be amplified
In the polymerase chain reaction (PCR), the sequence of bases in the primers is important because it _____.
nucleotides, primers, and polymerase
A molecular biologist has isolated a short segment of DNA that she wants to replicate in vitro. First she heats the DNA, which separates the two strands, and then she adds _____.
three
In the polymerase chain reaction (PCR) technique, a heating phase and a cooling phase alternate. An original sample of DNA would have to pass through how many total rounds of heating and cooling before a sample is increased eight times in quantity?
none of the above
Separating DNA fragments by gel electrophoresis is useful for all of the following except _____.
they are not restricted to genes, and are abundantly scattered throughout the genome
RFLPs have been tremendously useful for genomic mapping studies because _____.
a particular nucleotide sequence whose inheritance can be followed
A genetic marker is _____.
preparing a collection of large, overlapping genomic DNA fragments, and ordering them relative to each other
Preparing a physical map of the genome involves _____.
produces a ladder of DNA fragments, with each individual band labeled with one of four different fluorescent tags
The dideoxynucleotide chain-termination method _____.
Analyze the sequence using software that scans the sequence for telltale sequence elements such as promoters, transcription start and stop sites and so on.
Once an organism’s genome sequence has been determined, how do scientists generally start identifying all the genes within the genome?
25,000-30,000
The human genome is thought to contain about how many genes? (Concept 20.4E-Book)
adding a functioning version of a defective gene to the cells of an individual
Gene therapy involves _____.
The virus inserted the gene encoding the human enzyme into the normally expressed endogenous gene.
A molecular biologist used a retroviral vector to introduce a gene coding for a certain human enzyme into mouse cells. One cell line was isolated that was able to make the human enzyme, but it had lost the ability to express an endogenous, normally expressed gene in the process. What is the best explanation for these results?
the baby’s … Sam’s or Becky’s
fingerprints are used to determine whether Sam could be the father of Becky’s baby. Sam is not the father if _____ genetic fingerprint shows some bands not present in _____ genetic fingerprint.
the presence of various-sized fragments of DNA
DNA fingerprints used as evidence in a murder trial look something like supermarket bar codes. The pattern of bars in a DNA fingerprint shows _____
a rat with rabbit hemoglobin genes
Which of the following would be considered a transgenic organism?
the inserted (“foreign”) gene is expressed in the host organism
Transgenic organisms can be scientifically or commercially useful only if _____.
insert genes of interest into plant chromosomes
In genetic engineering, the highly active plasmid from Agrobacterium tumefaciens is used to _____
