BIOLOGY 172 Chapter 19.2: Biology 172 Reading 22: mRNA and phenotype in Eukaryotes
Document Summary
Reading #22- 19. 2: mrna to phenotype in eukaryotes. Once mrna is in the cytoplasm, there are many opportunities for gene regulation at levels of mrna stability, translation, and protein activity. Small regulatory rnas are short rna molecules that can block transcription, cleave/destabilize rrna or inhibit mrna translation: small interfering rna (sirna, micron rna (mirna) Both are transcribed from dna and form hairpin structures stabilized by base pairing in stem: enzymes in cytoplasm recognize these structures and cleave stem from hairpin, then cut up stem into shorter 20-25 base pair fragments. 5" (cid:272)ap is a (cid:373)ai(cid:374) re(cid:272)og(cid:374)itio(cid:374) stru(cid:272)ture for tra(cid:374)slatio(cid:374) i(cid:374)itiatio(cid:374), uses a(cid:271)out (cid:1006)5 protei(cid:374)s. Protein structure and chemical modification modulate protein effects on phenotype. After translation, the protein can alter phenotype of cell or organism by affecting metabolism, signaling, gene expression, or cell structure. Posttranslational modification are the processes after translation that modify structure and function: essential level of regulation!
