Unit Three- Translation, mRNA to Protein Flashcards
what is tRNAs formation and why
-complementary base on different regions of each tRNA causes it to fold into a clover
what is on the ends of tRNA
1-anticodon that is complementary to the codon on the mRNA
2- amino acid attachment site
how is mRNA made and what does it do
-what through transcription
-carries genetic code from nucleus to cytoplasm
-attaches to a ribosome
what is enzymes role in translation
-attach the amino acid to tRNA with the correct anticodon
-when attached to the anticodon they form aminoacyl tRNA complex
-catalyzed peptide bonds between amino acids in polypeptide chains
what are ribosomes composed of
-rRNA
-2 subunits
one large and one small
what are ribosomes binding sites
*to bind mRNA
P site- holds aa-tRNA & polypeptide
A site- brings the next amino acid to be added
E site- releases tRNA into cytoplasm and it exists
how does initiation in translation begin
-mRNA with start codon reaches cytoplasm & binds to the rRNA on the ribosomal SMALL subunit
-the initiator with anticodon UAC binds to LARGE subunit at the P site
-at the other end, tRNA has the amino acid MET which starts amino acid sequence
what is the first step of elongation in translation
the mRNA codon exposed from at A site binds to the ati codon of the incoming aa-tRNA
-enzyme catalyzes a peptide bond to connect the amino acid to MET
how does the amino acid chain move
-transferred from tRNA at the P site to the tRNA at the A site
-the ribosome then translocates 3 nuclotides along the mRNA IN 5’ TO 3’
how does termination begin in translation
-signalled by a stop codon on the mRNA
what happens during termination duirng translation
-polypeptide is cleaved from tRNA
-leaves ribosomes
-ribosome subunits come apart and are deactivated
