Translation and Mutations

Flashcards about Translation and Mutations vocabulary.

Translation

RNA-directed protein synthesis.

Transfer RNA (tRNA)

Recognize codons in the mRNA and link them to specific amino acids.

Aminoacyl tRNA synthetases

Make sure that the correct amino acid is attached to each tRNA (“charging”).

Ribosome

The workbench where aminoacyl tRNAs & mRNA are brought together during translation; catalyzes formation of the peptide bond between amino acids.

P site

Binds the tRNA bearing growing polypeptide chain.

A site

Binds the tRNA bearing the next amino acid to be added.

E site

Where tRNA exits the ribosome.

Initiation

Small ribosomal subunit binds mRNA and tRNA-Met (anticodon pairs with AUG start codon); large ribosomal subunit binds --> forms functional ribosome initiator tRNA bearing met is bound to the P site.

Codon recognition

Incoming amino acyl tRNA binds to codon at the A site.

Peptide bond formation

Catalyzed by peptidyl transferase activity of ribosome; polypeptide is transferred from tRNA in P site to the tRNA in the A site.

Translocation

Ribosome advances by one codon as the tRNA bearing the nascent polypeptide chain is transferred from the A site to the P site.

Termination

When the A site encounters stop codon, no amino acid can be added; release factor binds the A site; covalent bond between the tRNA and polypeptide at P site is hydrolyzed; completed polypeptide chain is released, ribosomal subunits dissociate.

Mutations

Heritable changes in DNA that can alter the expression or sequence of a gene or its products.

Silent mutations

Change nucleotide sequence, but not protein sequence.

Missense mutations

Change base sequence and amino acid sequence.

Nonsense mutations

Change codon to termination codon.