AP®︎ Biology: Topic 6.4 Flashcards

Synthesis of a polypeptide from an mRNA template at a ribosome.

Occurs on cytoplasmic ribosomes in both cell types and on rough ER ribosomes in eukaryotes.

Free ribosomes make cytosolic proteins; rough ER ribosomes make secreted or membrane proteins.

In prokaryotes, ribosomes begin translating mRNA while it is still being transcribed.

Initiation starts synthesis, elongation adds amino acids, and termination releases the finished polypeptide.

rRNA binds mRNA at AUG, and the first tRNA carrying methionine starts polypeptide synthesis.

A three-nucleotide mRNA sequence that specifies an amino acid or translation stop signal.

The rules matching mRNA codons to amino acids during protein synthesis.

Most amino acids are specified by more than one codon.

Almost all organisms use the same codon-to-amino acid assignments.

RNA that carries a specific amino acid and pairs its anticodon with an mRNA codon.

A three-nucleotide tRNA sequence complementary to an mRNA codon.

Repeated codon recognition and peptide bond formation extend the growing polypeptide chain.

A covalent bond joins adjacent amino acids as the polypeptide grows.

A stop codon ends translation and the completed polypeptide is released.

UAA, UAG, and UGA signal the end of translation rather than an amino acid.

Gene sequences determine amino acid sequences, which shape proteins and influence observable traits.

Changes in mRNA codons can alter amino acid sequence, protein structure, and phenotype.

Reverse transcriptase copies viral RNA into DNA, reversing the usual information flow.

Viral DNA inserts into the host genome, then is transcribed and translated to make new viruses.

Translation begins at AUG, then each mRNA codon is matched to an amino acid.

The shared genetic code across organisms supports that all life evolved from common ancestors.