USMLE (Fach) / Biochemistry - Molecular, Cellular, Techniques (Lektion)

Vorderseite Protein synthesis
Rückseite

Initiation:Eukaryotic initiation factors (eIFs) identify either the 5' cap or an internal ribosome entry site (IRES). IRES can be located at many places in an mRNA (most often 5' UTR). The eIFs then help assemble the 40S ribosomal subunit with the initiator tRNA and are released when the mRNA and the ribosomal 60S subunit assemble with the complex. Requires GTP.

Elongation:1. Aminoacyl-tRNA binds to A site (except for initiator methionine), requires an elongation factor and GTP.2. rRNA ("ribozyme") catalyzes peptide bond formation, transfers growing polypeptide to amino acid in A site.3. Ribosome advances 3 nucleotides toward 3' end of mRNA, moving peptidyl tRNA to P site (translocation).

Termination:Release factor recognizes stop codon and halts translation → completed polypeptide is released from ribosome. Requires GTP.

Diese Karteikarte wurde von estoffel erstellt.