Chapter 33, page 1 BCH 4054 Fall 2000 Chapter 33 Lecture Notes Slide 1 Chapter 33Protein Synthesis The chapter covers degradation of proteins as well. We will not have time to get into that subject. Slide 2 Prokaryotic Ribosomes•70S particle with 30S and 50S subunits•30S contains 16S RNA (1542 bases) and 21 peptides•50S contains 23S RNA (2904 bases), 5S RNA (120 bases) and 31 peptides.•RNA is cut from a precursor operon •(Fig 33.1)•Shapes have been discerned from both EM and X-ray studies.•Fig 33.3Recall that sizes of macromolecular complexes is operationally defined in terms of the sedimentation rate of the particle in a centrifugation experiment. “S” stands for Svedberg units. It is related to size, but not directly proportional because shape factors also affect sedimentation rate. (See page 157) Slide 3 Eukaryotic Ribosomes•80S particle with 40S and 60S subunits•40S contains 18S RNA (1874 bases) and 33 polypeptides•60S contains 28S RNA (4718 bases), 5.8S RNA (160 bases), 5S RNA (120 bases) and 49 polypeptides•Mitochondria have ribosomes similar to prokaryotic ribosomes
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