Chapter 20 - Biotechnology Flashcards
recombinant DNA
A DNA molecule made <em>in vitro</em> with segments from different sources.
biotechnology
The manipulation of organisms or their components to produce useful products.
genetic engineering
The direct manipulation of genes for practical purposes.
plasmid
A small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome; in DNA cloning, used as vectors carrying up to about 10,000 base pairs (10 kb) of DNA. Plasmids are also found in some eukaryotes, such as yeasts.
gene cloning
The production of multiple copies of a gene.
restriction enzyme
An endonuclease (type of enzyme) that recognizes and cuts DNA molecules foreign to a bacterium (such as phage genomes). The enzyme cuts at specific nucleotide sequences (restriction sites).
restriction site
A specific sequence on a DNA strand that is recognized and cut by a restriction enzyme.
restriction fragment
A DNA segment that results from the cutting of DNA by a restriction enzyme.
sticky end
A single-stranded end of a double-stranded restriction fragment.
DNA ligase
A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3’ end of one DNA fragment (such as an Okazaki fragment) to the 5’ end of another DNA fragment (such as a growing DNA chain).
cloning vector
In genetic engineering, a DNA molecule that can carry foreign DNA into a host cell and replicate there. Cloning vectors include plasmids and bacterial artificial chromosomes (BACs), which move recombinant DNA from a test tube back into a cell, and viruses that transfer recombinant DNA by infection.
genomic library
A set of cell clones containing all the DNA segments from a genome, each within a plasmid, BAC, or other cloning vector.
bacterial artificial chromosome
A large plasmid that acts as a bacterial chromosome and can carry inserts of 100,000 to 300,000 base pairs (100-300 kb).
complementary DNA (cDNA)
A double-stranded DNA molecule made <em>in vitro</em> using mRNA as a template and the enzymes reverse transcriptase and DNA polymerase. A cDNA molecule corresponds to the exons of a gene.
cDNA library
A gene library containing clones that carry complementary DNA (cDNA) inserts. The library includes only the genes that were transcribed in the cells whose mRNA was isolated to make the cDNA.
nucleic acid hybridization
The process of base pairing between a gene and a complementary sequence on another nucleic acid molecule.
nucleic acid probe
In DNA technology, a labeled single-stranded nucleic acid molecule used to located a specific nucleotide sequence in a nucleic acid sample. Molecules of the probe hydrogen-bond to the complementary sequence wherever it occurs; radioactive, fluorescent, or other labeling of the probe allows its location to be detected.
expression vector
A cloning vector that contains a highly active bacterial promoter just upstream of a restriction site where a eukaryotic gene can be inserted, allowing the gene to be expressed in a bacterial cell. Expression vectors are also available that have been genetically engineered for use in specific types of eukaryotic cells.
electroporation
A technique to introduce recombinant DNA into cells by applying a brief electrical pulse to a solution containing the cells. The pulse creates temporary holes in the cell’s plasma membranes, through which DNA can enter.
polymerase chain reaction (PCR)
A technique for amplifying DNA <em>in vitro</em> by incubating it with specific primers, a heat-resistant DNA polymerase, and nucleotides.
gel electrophoresis
A technique for separating nucleic acids or proteins on the basis of their size and electrical charge, both of which affect their rate of movement through an electric field in a gel made of agarose or another polymer.
restriction fragment length polymorphism (RFLP)
A single nucleotide polymorphism (SNP) that exists in the restriction site for a particular enzyme, thus making the site unrecognizable by that enzyme and changing the lengths of the restriction fragments formed by digestion with that enzyme. A RFLP can be in coding or noncoding DNA.
Southern blotting
A technique that enables specific nucleotide sequences to be detected in samples of DN A. It involves gel electrophoresis of DNA molecules and their transfer to a membrane (blotting), followed by nucleic acid hybridization with a labeled probe.
Northern blotting
A technique that enables specific nucleotide sequences to be detected in samples of mRNA. It involves gel electrophoresis of RNA molecules and their transfer to a membrane (blotting), followed by nucleic acid hybridization with a labeled probe.
