LIFE 120 Lecture Notes - Lecture 34: Fluid Mosaic Model, Polysome, Protein Kinase
Document Summary
Completing and targeting the functional protein: often translation is not sufficient to make a functional protein, polypeptide chains are modified after translation or targeted to specific sites in the cell. Protein folding: during synthesis, a polypeptide chain spontaneously coils and folds into its three-dimensional shape. Translation can begin while transcription is still in progress. Types of small scale mutations: small-scale mutations within a gene can be divided into two general categories, nucleotide-pair substitutions. A nucleotide-pair substitution replaces one nucleotide and its partner with another pair of nucleotides: one or more nucleotide-pair insertions or deletions (frameshift mutations) Substitutions: silent mutations have no effect on the amino acid produced by a codon because of redundancy in the genetic code, missense mutations still code for an amino acid, but not the correct amino acid. Substitution mutations are usually missense mutations: nonsense mutations change an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein.
