2.4 Flashcards
(15 cards)
is the synthesis of polypeptide
using the genetic information encoded in
an mRNA molecule. There is a change of
“language” from ribonucleotides to
amino acids.
Translation
are about 70-80 nucleotides long and
have cloverleaf characteristic structures
resulting from complementary base pairing
between different molecule regions.
-fold into similar compact L shapes,
which are possibly necessary during the
translation process for the tRNAs to fit onto
ribosomes.
-interprets the mRNA by acting as an
adaptor molecule that recognizes both the
codon and the encoded amino acid.
tRNAs
located at the other end of
the folded tRNA base pairs with a
complementary codon on the mRNA template.
Anticodon loop
is a catalytic complex where
protein synthesis takes place.
ribosome
A ribosome has three binding sites for
tRNA:
A site, P site, E site
(aminoacyl-tRNA binding
site) that holds the tRNA carrying the next
amino acid to be added;
A site
(peptidyl-tRNA binding site) that holds the
tRNA carrying the growing polypeptide
chain;
P site
serves as an exit
site for discharged tRNA.
E site
brings together mRNA, tRNA
with the first amino acid, and the two
ribosomal subunits:
initiation
elongation factors:
Codon recognition
Peptide bond formation
Translocation
An incoming
aminoacyl tRNA binds to the codon in the A
site.
Codon recognition
Peptidyl-
transferase joins the polypeptide from the P
site to the newly arrived amino acid in the A
site.
Peptide bond formation
The tRNA in the A site with
the growing polypeptide is translocated to
the P site. The tRNA in the P site moves to the
E site.
translocation
is
performed simultaneously based on the sequence of amino
acids but it does not specify the final structure of protein.
protein folding and it is aided by chaperonins
is part of a complex that identifies
the signal peptide and carries the ribosome to the endoplasmic
reticulum through multiprotein translocation.
signal recognition particle
