Gene Expression


A site

ribosome binding site where a charged tRNA associated with an amino acid first attaches


protein that increases transcription of a gene

aminoacyl-tRNA synthetase

enzyme that attaches an amino acid to a tRNA molecule


sequence of three nucleotides of a tRNA molecule that pairs with the complement on an mRNA strand during protein synthesis

central dogma of biology

concept that genetic information flows from DNA to RNA to proteins

E site

ribosome binding site where the tRNA is ejected following translation


region of DNA that encourages transcription by binding proteins that help initiate it


DNA sequence within a gene sequence that codes for a polypeptide sequence. Exons must be combined during mRNA processing.


DNA sequence within a gene sequence that does not code for a specific protein. Introns must be removed from the pre-mRNA during processing.

lac operon

gene cluster that codes for enzymes that import and digest the sugar lactose in E. coli and other bacteria

messenger RNA (mRNA)

RNA molecule made from a DNA template, contains the complementary gene sequence, that is, the sequence opposite to the DNA strand


collection of genes that are transcribed together and contain at least two regions of control, called a promoter and an operator

P site

ribosome binding site where an amino acid is added to the growing peptide chain

pluripotent stem cell

cell able to reproduce indefinitely and develop into other types of specialized cells


addition of a poly-A tail, or multiple adenosine monophosphates, to an mRNA strand


sequence of DNA to which RNA polymerase binds to initiate the process of transcription


enzyme that functions in protein degradation


enzyme complex that modifies or degrades a protein


proteins expressed by the genome of an organism or a cell throughout its life or at a specified time under certain environmental conditions

regulatory DNA sequence

nucleotide sequence that can increase or decrease gene expression


protein that inhibits transcription of a gene

ribosomal RNA (rRNA)

RNA component of ribosomes that catalyzes peptide bond formation

RNA polymerase

enzyme used in the formation of RNA

RNA splicing

process by which introns are removed from mRNA and exons are joined together following transcription


stop signal on the DNA strand that halts synthesis of mRNA


formation of messenger RNA from the template DNA strand to be used to build proteins

transcription factor

protein that binds to the regulatory DNA sequence to control transcription

transfer RNA (tRNA)

molecule that carries each amino acid to the strand of mRNA during translation of protein synthesis


assembly of amino acids into proteins in ribosomes through the reading of mRNA by tRNA and the ribosome