Polymerase Chain Reaction (PCR) Glossary


An increase in the number of copies of a specific DNA fragment.


A genetic structure in a cell composed of condensed DNA, which contains the genetic code for an organism.


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.


A process which breaks the H-bonds between DNA bases, making the molecule become single-stranded.


Asexual propagation of a plant by breaking the crown or suckers (must contain a node) to producte an identical plant.


(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.


A technique which uses electricity to separate molecule fragments according to size so they can be studied.


The combinations of all the conditions external to the genome that potentially affect gene expression and the phenotype of a plant.


A protein that catalyzes, or speeds up, a specific biochemical reaction without changing the nature of the reaction.


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).


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.


All the genetic material in the haploid set of chromosomes for a particular organism.


The stage of cell division when DNA is replicated; a copy of each chromosome is made.


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.


A type of cell division which results in the formation of gametes, cells with half the normal number of chromosomes.


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.


The building blocks of DNA and RNA; adenine, cytosine, guanine, thymine (DNA only), and uracil (RNA only).


(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.


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.


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.


The copying of a DNA molecule in a cell.


Copied DNA. To make copies of DNA.


The copying of a DNA molecule.


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.


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.