Actin is one of the most abundant proteins in eukaryotes, where it is found throughout the cytoplasm. Its amino acid sequence is one
of the most highly conserved of the proteins as it has changed
very little over the course of evolution, differing by no more than
20% in species as diverse as algae and humans. Actin contributes
to processes such as intracellular transport of vesicles and
organelles, muscular contractions, cellular migration, and gene
expression. What two steps combine to form actin through the
process of protein synthesis?