BIO 201 Lecture Notes - Lecture 38: Transfer Rna, Base Pair, Stop Codon

• School: University at Buffalo
• Department: Biological Sciences
• Course: BIO 201
• Professor: Lara Hutson

Document Summary

The correct a. a. is selected because its trna anticodon base pairs with the mrna codon. Anticodon sequence is the reverse complement of the codon sequence, binds to the mrna. Only the trna with the correct anticodon can bind to the mrna. Different trna molecules (transcribed from different genes) have unique 3-nt anticodon sequences. Aminoacyl-trna synthetase(enzyme) adds a(cid:374) a(cid:373)i(cid:374)o a(cid:272)id to the (cid:1007)" e(cid:374)d of ea(cid:272)h trna. This creates a high-energy bond. (*energy from atp*) trna binds to trna synthetase, which attaches amino acid only if trna has the correct a(cid:374)ti(cid:272)odo(cid:374) (cid:894) y(cid:374)thetase (cid:862)reads(cid:863) a(cid:374)ti(cid:272)odo(cid:374)(cid:895) Tra(cid:374)slatio(cid:374) i(cid:374) three (cid:862)steps(cid:863) (do not need to know) Ri(cid:271)oso(cid:373)e (cid:271)i(cid:374)ds to 5" (cid:272)ap a(cid:374)d poly a tail (cid:894)(cid:374)ot sho(cid:449)(cid:374)(cid:895) Ri(cid:271)oso(cid:373)e s(cid:272)a(cid:374)s (cid:373)rna (cid:271)egi(cid:374)(cid:374)i(cid:374)g at 5" (cid:272)ap a(cid:374)d stops at first start codon (aug, encodes methionine) Methionyl-trna (anticodon cau) enters ribosome and binds to codon. *requires gtp: elongation trna #2 enters ribosome *requires gtp* Ribosome moves down 1 codon (translocation) *requires gtp*