Gene Cloning Part 2: Making and Screening Gene Libraries Glossary

amino acid

The basic building blocks of proteins. The sequence of amino acids in a protein and protein function are determined by the genetic code.


Immune system protein made by mammals to specifically bind to foreign molecules allowing the mammal to fight off disease.


Genetically identical cells or organisms all derived from a single ancestor by asexual or parasexual methods.

cloned gene

A copy of a gene that has been combined with a plasmid and placed into a bacteria cell.


Three consecutive nucleotides in an RNA molecule that code for a single amino acid.


A group of identical cells (or bacteria) that develop from a single cell when the cell divides multiple times. The cells are considered 'clones' of the original cell.


(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 sequence

The order of nucleotides, whether in a fragment of DNA, a gene, a chromosome, or an entire genome.


Special protein molecules which function in catalyzing chemical reactions.


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.

gene cloning

Finding and making copies of a specific gene. This is the first part of the genetic engineering process.


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


(messenger ribonucleic acid) The message made during transcription by reading the DNA sequence to build a particular protein. A single-stranded nucleic acid similar to DNA but having a ribose sugar rather than deoxyribose sugar and a uracil rather than thymine as one of the bases.


(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.


A specific DNA sequence to which RNA polymerase binds and initiates transcription. This region contains information which regulates when and how often the gene is transcribed and ultimately the amount of protein it produces.


A large molecule composed of one or more chains of amino acids in a specific order. Proteins are necessary for the structure, function, and regulation of an organism's cells, tissues, and organs. Each protein has a unique function determined by its shape.

RNA Polymerase

An enzyme that catalyzes the synthesis of RNA by copying the nucleotide sequence of the DNA.


Determination of the order of nucleotides in a DNA or RNA molecule or the order of amino acids in a protein.


The process by which the nucleotide sequence of DNA is copied into a single-stranded molecule of RNA. The nucleotide sequence of the RNA created is complementary to the DNA sequence except all thymine molecules are replaced with uracil molecules.


The process following transcription during which the nucleotide sequence of mRNA is read and 'translated' into a chain of amino acids (protein). The mRNA sequence is read three nucleotides (codon) at a time, and each codon codes for a specific amino acid.