70 likes | 89 Views
Learn about polysomes, the group of ribosomes bound to mRNA, and the process of polypeptide elongation where amino acids are added. Explore tRNA binding, peptide bond formation, and more.
E N D
Polysomes and polypeptide elongation Sun Hwa Dong
Polysomes (=Polyribosomes) • Group of ribosomes bound to a mRNA • Read one strand of mRNA simultaneously • To translate, each ribosome follows repeated steps • After each repetition, one amino acid is added to elongating polypeptide
Polypeptide Elongation • A tRNA – amino acid approaches the ribosome and binds at A site. • 2 tRNAs can be at a ribosome at one time; the anticodons are paired to codons • Peptide bond formation attaches the peptide chain to the newly arrived amino acid • The ribosomes moves forward; “empty” tRNA exists from the E site; the next amino acid-tRNA complex is approaching the ribosome
Vocabulary • Polysomes • mRNA, tRNA • Amino acid • Codon, anticodon • Polypeptide elongation
Bibliography • Study guide pg 64 • http://classes.midlandstech.edu/carterp/Courses/bio101/chap14/chap14.htm • http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookprotsyn.html