I. DNA gene—> mRNA transcript —> amino acid chain
II. Codon: 3-base-long sequence on mRNA that corresponds to particular amino acids
- total of 64 possible codons
- total of 20 amino acids
- Redundant codons = greater than 1 codon per amino acid
III. Ribosome attaches to mRNA at SHINE-DELGARNO sequence, a specific series of bases on mRNA that are complementary to sequence of bases in rRNA.
IV. Ribosome moves ONE BASE AT A TIME down mRNA until it reaches AUG. AUG defines "reading frame" of mRNA
V. tRNA: cloverleaf-shaped w/ anticodon on one side, amino acid on other. rRNA brings in tRNA's and matches them w/ codons on mRNA
VI: rRNA forms bond between amino acids that are adjacent to each other. tRNA detaches from amino acid.
VII. Because there is no tRNA w/ anticodon complementary to stop codons, rRNA pauses at stop codon. Proteins called RELEASE FACTORS bind w/ stop codons, catalyze release of amino acid chain from ribosome and ribosome from mRNA.
Kassie Hein