7.3 Translation Flashcards
translation
- encoded message read by ribosome and presence of transfer RNA molecules, ribosomes assemble one at a time into polypeptide chain
tRNA
regions that base pair w themselves winding into 4 double helical segments to form clover leaf patterns
anticodon
complementary sequence of base pairs on tRNA that corresponds to anticodon
aminoacylation
tRNA molecule bound to corresponding amino acid
aminoacyl-tRNA
molecule of transfer RNA to its associated amino acid
Ribosomes
- carry out protein synthesis by translating mRNA into chains of amino acids
- use mRNA molecule to join amnio acid in ordered sequence to make polypeptide chain
- special binding sites that bring together mRNA w aminoacyl-tRNA
A (aminoacyl) site
incoming aminoacyl-tRNA carrying out next amino acid to add to polypeptide chain that binds to mRNA
P (peptidyl) site
when tRNA carrying growing polypeptide is bound
Initiating Translation
- triggered by large and small ribosome subunits binding to 5’ cap of mRNA
- start codon is AUG corresponding to methionine
- tRNA’s anticodon is UAC delivers methionine to ribosomes
reading frame
system for operating base pair sequences into readable codons
Elongating Polypeptide
- incoming tRNA molecules deliver next appropriate amino acid to ribosomes as dictated by reading frame of 3 bases
termination of protein synthesis
- occurs when stir codon is read by ribosomes
- stop codons are UAG, UGA, UAA
protein synthesis in prokaryotes and eukaryotes
- more than one ribosome can transfer mRNA molecule at a time resulting in polysome
polysome
complex formed when multiple ribosome attach to same mRNA molecule to facilitate rapid translation