Chapter 20: DNA Tools and Biotechnology Flashcards
DNA Technology
Techniques for sequencing and manipulating DNA
Biotechnology
Manipulation of organisms or their components to produce useful products
Nucleic Acid Hybridization
Base pairing of one strand of a nucleic acid to the complementary sequence on a strand from another nucleic acid molecule
Genetic Engineering
Direct manipulation of genes for practical purposes
DNA Sequencing
Determining the complete nucleotide sequence of a gene or DNA segment
DNA Cloning
Production of multiple copies of a specific DNA segment
Plasmid
- Small, circular, double-stranded DNA molecule
- Carries accessory genes separate from those of a bacterial chromosome
Recombinant DNA
DNA molecule made in vitro with segments from different sources
Gene Cloning
Production of multiple copies of a gene
Cloning Vector
In genetic engineering, a DNA molecule that can carry foreign DNA into a host cell and replicate there
Restriction Enzyme
- Endonuclease (type of enzyme)
- Recognizes and cuts DNA molecules foreign to a bacterium (i.e. phage genomes)
- Cuts specific nucleotide sequences (restriction sites)
Restriction Site
DNA sequence on a DNA strand that is recognized and cut by a restriction enzyme
Restriction Fragment
DNA segment that results from the cutting of DNA by a restriction enzyme
Sticky End
Single-stranded end of a double-stranded DNA restriction fragment
DNA Ligase
- Linking enzyme essential for DNA replication
- Catalyzes the covalent bonding of the 3’ end of a new DNA fragment ot the 5’ end of a growing chain
Gel Electrophoresis
Technique for separating nucleic acids or proteins on the basis of their size and electrical charge, both which affect their rate of movement through an electrical field in a gel made of agarose or another polymer
Polymerase Chain Reaction (PCR)
Technique for amplifying DNA in vitro by incubating it with specific primers, a heat-resistant DNA polymerase, and nucleotides
Expression Vector
- Cloning vector
- Contains a highly active bacterial promoter just upstream of a restriction site where the eukaryotic gene can be inserted, allowing the gene to be expressed in a bacterial cell
Electroporation
- Technique used 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 cells’ plasma membrane, where DNA can enter
Nucleic Acid Probe
- In DNA technology
- Labeled single-stranded nucleic acid molecule
- Used to locate 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
In Situ Hybridization
- Technique using nucleic acid hybridization with a labeled probe
- Detects the location of specific mRNA in an intact organism
Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR)
- Technique for determining expression of a particular gene
- Uses reverse transcriptase and DNA polymerase to synthesize cDNA from all the mRNA in a sample
- Subjects the cDNA to PCR amplification using primers specific for the gene of interest
Complementary DNA (cDNA)
- Double-stranded DNA molecule made in vitro using mRNA as a template and the enzymes reverse transcriptase & DNA polymerase
- cDNA molecule corresponds to the exons of a gene
DNA Microarray Assay
- Method to detect and measure the expression of thousands of genes at one time
- Tiny amounts of a large number of single-stranded DNA fragments representing different genes are fixed to a glass slide and tested for hybridization with samples of labeled cDNA
In Vitro Mutagenesis`
- Technique used to discover the function of a gene
- Clones the gene, introduces specific changes into the cloned gene’s sequence, reinserts the mutated gene into a cell, studies phenotype of the mutant
RNA Interference (RNAi)
- Mechanism of silencing the expression of specific genes
- Double-stranded RNA molecules that match the sequence of a particular gene are processed into siRNAs that either block transition or trigger the degradation of the gene’s messenger RNA
- Happens naturally in some cells
- Can be carried out in laboratory experiments
Genome-Wide Association Study
- Large-scale analysis of the genomes of many people having a certain phenotype or disease
- Aims to find genetic markers that correlate with that phenotype or disease
Single Nucleotide Polymorphism (SNP)
Single base-pair site in a genome where nucleotide variation is found in at least 1% of the population
Stem Cell
Any relatively unspecialized cell that can produce (during a single division) one identical daughter cell and one more specialized daughter cell that can undergo furht differentiation
Totipotent
Describing a cell that can give rise to all parts of the embryo and adult as well as extraembryonic membranes in species that have them
Pluripotent
Describing a cell that can give rise to many, but not all, parts of an organism
Induced Pluripotent Stem Cells (iPS)
- Pluripotent stem cells
- Created by reversing differentiation of a non-pluripotent cell
- Virtually identical to embryonic stem cells
- Circumvents the need to destroy embryos
Gene Therapy
Introduction of genes into an afflicted individual for therapeutic purposes
Transgenic
Pertaining to an organism whose genome contains a gene introduced from another organism of the same or a different species
Genetic Profile
- An individual’s unique set of genetic markers
- Detected most often today by PCR or, previously, by electrophoresis and nucleic acid probes
Short Tandem Repeat (STR)
- Simple sequence DNA
- Contains multiple tandemly repeated units of two to five nucleotides
- Variations in STRs act as genetic markers in STR analysis
- Used to prepare genetic profiles
Genetically Modified Organism (GMO)
An organism that has acquired one or more genes by artificial means
Transgenic Organism
A genetically modified organism that has acquired a gene from another species
