Polymerase Chain Reaction (PCR) Glossary
- amplification
An increase in the number of copies of a specific DNA fragment.
- chromosome
A genetic structure in a cell composed of condensed DNA, which contains the genetic code for an organism.
- complementary
Term used in science to refer to the normal nucleotide-pairing in DNA replication, with cytosine pairing with guanine and adenine pairing with thymine.
- denaturation step
The first temperature step in PCR. During this step, the DNA is made single-stranded, denatured.
- denature
A process which breaks the H-bonds between DNA bases, making the molecule become single-stranded.
- division
Asexual propagation of a plant by breaking the crown or suckers (must contain a node) to producte an identical plant.
- DNA
(deoxyribonucleic acid) The molecule that encodes genetic information. DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. It is the fundamental substance of which genes are composed.
- DNA polymerase
The enzyme which catalyzes the reaction of adding new DNA bases to a growing DNA strand.
- DNA replication
The process in which a DNA molecule is copied. This takes place in PCR and naturally in cell division.
- DNA sequence
The order of nucleotides, whether in a fragment of DNA, a gene, a chromosome, or an entire genome.
- DNA template
That particular portion of a DNA molecule which is copied in PCR.
- electrophoresis
A technique which uses electricity to separate molecule fragments according to size so they can be studied.
- environment
The combinations of all the conditions external to the genome that potentially affect gene expression and the phenotype of a plant.
- enzyme
A protein that catalyzes, or speeds up, a specific biochemical reaction without changing the nature of the reaction.
- gamete
A mature male or female reproductive cell (sperm or ovum) containing half of the total number of chromosomes in a cell (i.e., humans have 46 chromosomes per cell; gametes would have 23).
- gene
The fundamental unit of heredity that carries genetic information from one generation to the next. A gene is an ordered sequence of nucleotides located on a particular position on a particular chromosome that encodes a specific functional protein.
- genome
All the genetic material in the haploid set of chromosomes for a particular organism.
- interphase
The stage of cell division when DNA is replicated; a copy of each chromosome is made.
- marker
An easy to detect trait controlled by a known gene. Markers, such as antibiotic or herbicide resistance, are often used to determine if an organism is transgenic.
- meiosis
A type of cell division which results in the formation of gametes, cells with half the normal number of chromosomes.
- nucleotide
A subunit of DNA or RNA consisting of a nitrogenous base (adenine, guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine in RNA), a phosphate molecule, and a sugar molecule. Thousands of nucleotides are linked together to form a DNA strand.
- nucleotides
The building blocks of DNA and RNA; adenine, cytosine, guanine, thymine (DNA only), and uracil (RNA only).
- PCR
(polymerase chain reaction) A method for replicating a particular sequence of DNA in vitro. Used to generate greater amounts of DNA for analysis or to determine if a particular sequence exists.
- primer
Small section of DNA nucleotides which bind to the single-stranded DNA template during PCR. These can be sequences specific for a gene or totally random, depending upon the experiment’s objective.
- proteins
Large molecules composed of one or more chains of amino acids in a specific order. Proteins are necessary for the structure, function, and regulation of the organism's cells, tissues, and organs. Each protein has a unique function determined by its shape.
- replicate
The copying of a DNA molecule in a cell.
- replicated
Copied DNA. To make copies of DNA.
- replication
The copying of a DNA molecule.
- RNA
Ribonucleic Acid. A single-stranded nucleic acid similar to DNA but having a uracil rather than thymine as one of the nucleotides. The RNA strand carries the coded information from the nucleus to the cytoplasm where protein production occurs.
- Taq
A DNA polymerase often used in PCR which can withstand high temperatures.
- thermal cycler
The machine used in PCR which can be programmed for the heating and cooling cycles.