DNA tools and biotechnology

Therapeutic cloning refers to __________.
the use of cloned embryos as a source of stem cells that could be used to treat disease

In the polymerase chain reaction (PCR), the sequence of bases in the primers is important because it __________.
determines which segment of the genome will be amplified

The process that uses nucleic acid probes to study gene expression in intact organisms is called __________.
in situ hybridization

The efficiency of cloning, and the ability to generate healthy cloned animals, has been largely hampered by the difficulty of __________.
completely reversing epigenetic alterations in donor cell nuclei such as DNA methylation and chromatin packing

A pluripotent embryonic stem cell __________.
can differentiate into many different cell types

In Gurdon’s work with nuclear transplantation in frogs, which of the following characteristics of donor cells affected the extent to which the donor cell nuclei could support normal development in the egg cells that received the donor nuclei?
The older the donor nuclei, the lower the percentage of normally developing tadpoles

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?
Three

Which 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

In recombinant methods, the term vector refers to __________.
a plasmid or other agent used to transfer DNA into a living cell

The term “STR” stands for __________.
short tandem repeat

Reverse transcriptase produces __________ from an RNA template.
cDNA

What is the source of the reverse transcriptase used in recombinant DNA technology?
Retroviruses

Which of the following statements best describes gene therapy?
Gene therapy adds functioning versions of a defective gene to somatic cells.

Where in a DNA strand do restriction enzymes cut the strand?
At symmetrical sequences of bases

What do DNA microarray assays allow scientists to study regarding gene expression?
These assays allow scientists to identify networks of gene expression across an entire genome.

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 __________.
work backward from mRNA to make a version of the gene without introns

What is a “pharm” animal?
a transgenic organism that expresses a foreign gene that was added to the zygote

Bacteria use restriction enzymes to __________.
destroy foreign DNA

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 __________.
the fragments will bond to other fragments with complementary single-stranded ends

How does the process of dideoxyribonucleotide chain termination sequencing determine the base-pair sequence in a piece of DNA?
One strand of a DNA fragment is used as a template for synthesis of a nested set of complementary fragments; these are further analyzed to yield the sequence.

In the PCR process, once the identified segment of DNA is heated to separate the strands, what substances are then added to facilitate the copying of the segment?
primers, nucleotides, and polymerase

Which of the following enzymes is key to the automation of PCR (polymerase chain reactions)?
Taq polymerase

Which of the following statements best describes the process of in vitro mutagenesis?
Specific mutations are introduced into a cloned gene, and the mutated gene is returned to the cell in such a way that it disables (“knocks out”) the normal cellular copies of the same gene

One method for cloning organisms is nuclear transplantation. What happens in this process?
The nucleus of an unfertilized egg is removed and replaced with the nucleus of a differentiated cell

Which of the following describe(s) concerns regarding genetically modified (GM) organisms used as food?
All of the listed responses are correct.

What enzyme is used to bind DNA fragments with sticky ends that have hydrogen bonded to each other?
DNA ligase

__________ can give rise to any type of cell whereas __________ can give rise to a subset of cell types.
Embryonic stem cells; adult stem cells

The expression of the PAX-6 gene when vertebrate and fruit fly versions of the gene are exchanged between these animal groups illustrates __________.
the common ancestry in the evolution of these animal groups

A nucleic acid probe is used to __________.
identify genes that have been inserted into bacterial plasmids or separated by electrophoresis

DNA fingerprints used as evidence in a murder trial look something like supermarket bar codes. The pattern of bars in a DNA fingerprint shows __________.
the presence of various-sized fragments of DNA