From DNA To Proteins - Translation Flashcards
Genetic Code Table
A table containing codons that can be used to translate a genetic code into a sequence of amino acids.
Polypeptide
Chain of amino acids linked by peptide bonds; also called a protein.
Protein Structure
The arrangement of the chains of amino acids in proteins. It has several levels of organization (primary, secondary, tertiary, and quaternary).
Peptide Bond
Chemical bond that connects amino acids in a protein.
Amino Acid
Repeating unit of proteins; each consists of a central carbon atom bonded to an amino group, a hydrogen atom, a carboxyl group, and an R group.
Nonoverlapping Genetic Code
Refers to the fact that, generally, each nucleotide is part of only one codon and encodes only one amino acid in a protein.
Sense Codon
Codon that specifies an amino acid in a protein.
Universal Genetic Code
Refers to the fact that particular codons specify the same amino acids in almost all organisms.
Codon
Sequence of three nucleotides that encodes one amino acid in a protein.
Degenerate Genetic Code
Refers to the fact that the genetic code contains more codons than are needed to specify all 20 common amino acids.
Kozak Sequence
A sequence that functions as the protein translation initiation site in most eukaryotic mRNA transcripts.
Initiation (Start Codon)
The first codon of the mRNA to specify an amino acid (fMet in bacterial cells; Met in eukaryotic cells); most often AUG.
Isoaccepting tRNAs
Different tRNAs that accept the same amino acid but have different anticodons.
Synonymous Codons
Different codons that specify the same amino acid.
Initiation Of Translation
The process in which initiator tRNA, small and large ribosomal subunits are assembled by eukaryotic initiation factors into a ribosome at the initiation codon of mRNA.
Termination Of Translation
The stage of translation when a stop codon in the mRNA enters the A site. Stop codons are recognized by proteins called release factors, which fit neatly into the P site (though they aren’t tRNAs).
Nonsense Codon
Codon in mRNA that signals the end of translation. Also called a stop codon.
Stop (Termination) Codon
Codon in mRNA that signals the end of translation. The three common stop codons are UAA, UAG, and UGA.
Elongation Of Translation
The stage of translation in which the nascent polypeptide chain extends by one amino acid during one elongation cycle.
Wobble
Base pairing between codon and anticodon in which there is nonstandard pairing, usually at the third 3’ position of the codon; allows more than one codon to pair with the same anticodon.
tRNA charging
Chemical reaction in which an aminoacyl-tRNA synthetase attaches an amino acid to its corresponding tRNA.
Reading Frame
Particular way in which a nucleotide sequence is read in groups of three nucleotides (codons) in translation; begins with a start codon and ends with a stop codon.
Initiation Factors
Proteins that bind to the small subunit of the ribosome during the initiation of translation.
Ribosome
An intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell.
Aminoacyl-tRNA Synthetase
Enzyme that attaches an amino acid to a tRNA. Each of these recognizes a particular amino acid.
Small Ribosomal Subunit
The smaller of the two subunits of a functional ribosome.
Aminoacyl (A) Site
One of the three sites in a ribosome occupied by a tRNA during translation. All charged tRNAs (with the exception of the initiator tRNA) first enter this site.
Large Ribosomal Subunit
The larger of the two subunits of a functional ribosome.
Peptidyl (P) Site
One of the three sites in a ribosome occupied by a tRNA during translation. In the elongation stage, tRNAs move from the aminoacyl (A) site into this site.
Exit (E) Site
One of the three sites in a ribosome occupied by a tRNA during translation. In the elongation stage, the tRNA moves from the peptidyl (P) site to this site, from which it then leaves the ribosome.
Elongation Factors
Proteins that function at the ribosome, during protein synthesis, to facilitate translational elongation from the formation of the first to the last peptide bond of a growing polypeptide.
Polyribosome
Messenger RNA molecule with several ribosomes attached to it.
Release Factor
Protein required for the termination of translation; binds to a ribosome when a stop codon is reached and stimulates the release of the polypeptide chain, the tRNA, and the mRNA from the ribosome.
Translocation
Movement of a ribosome along mRNA during translation.
