Transcription and Translation Part 2 - RNA Types and Protein Synthesis

Vocabulary flashcards reviewing key concepts, structure and function of RNA types, ribosome structure, genetic code characteristics, and stages of translation.

Messenger RNA (mRNA)

A short, unstable, single-stranded RNA molecule corresponding to a gene encoded within DNA that serves as an intermediary between DNA and protein to direct protein synthesis.

5' Cap

A structure on mRNA important for ribosomal recognition and RNA stability.

Poly(A) Tail

A structure at the 3' end of mRNA that maintains stability for a length of time; when critically short, the mRNA is destroyed.

Ribosomal RNA (rRNA)

Longer, stable RNA molecules composing 60% of a ribosome's mass that ensure proper alignment of mRNA, tRNA, and ribosome, and catalyze peptide bond formation.

Transfer RNA (tRNA)

A short (70-90 nucleotides), stable RNA molecule with extensive intramolecular base pairing that carries the correct amino acid to the site of protein synthesis in the ribosome.

Acceptor Stem

The region at the 3'-end of a tRNA molecule where a specific amino acid is added by aminoacyl-tRNA synthetase.

Anticodon Loop

A loop on tRNA that complementary base pairs with an mRNA codon to ensure the appropriate amino acid is brought to the ribosome complex.

Ribosomes

Universal ribonucleoprotein particles consisting of two subunits (small and large) that translate the genetic code into proteins.

A Site (Acceptor site)

The ribosomal site where incoming charged aminoacyl-tRNAs enter during translation.

P Site (Peptidyl site)

The ribosomal binding site that holds the tRNA attached to the growing polypeptide chain.

E Site (Exit site)

The ribosomal binding site where an uncharged tRNA moves to exit the ribosome.

Codon

A sequence of three bases in mRNA that corresponds to a specific amino acid.

AUG

The start codon in mRNA that marks the start of translation and specifies the amino acid Methionine (Met).

STOP Codons

The three mRNA codons (UAA, UAG, UGA) that initiate the termination of translation.

Genetic Code Redundancy

The feature of the genetic code where each codon specifies only one amino acid, but most amino acids are encoded by more than one codon.

Translation Initiation

The process where the small ribosomal subunit and initiator tRNA recognize the 5' cap, scan for the AUG start codon, and assemble with the large ribosomal subunit.

Translocation

The movement during translation elongation where the large ribosomal subunit shifts one codon, transferring the growing polypeptide chain to the P site and the uncharged tRNA to the E site.

Release Factor

A protein that recognizes a stop codon in the A site, causing the translational complex to dissociate and release the completed polypeptide.

Polyribosome (Polysome)

A structure composed of multiple individual ribosomes translating a single mRNA molecule simultaneously.

Ribosome Structural Sites Diagram

A diagram illustrating the arrangement of the large subunit, small subunit, and the three functional binding sites (E-Site, P-Site, and A-Site) of a ribosome.