They translate the information encoded in messenger RNA (mRNA) into a polypeptide.
|Link to a description of the process|
Then, before these proteins reach their final destinations, they undergo a series of processing steps in the Golgi apparatus.
|Link to discussion of Protein Kinesis: the pathways taken by proteins synthesized on the endoplasmic reticulum.|
|Link to discussion of the evolution of mitochondria.|
This table gives some of the data. (S values are the sedimentation coefficient: a measure of the rate at which the particles are spun down in the ultracentrifuge. S values are not additive. nts = nucleotides.)
|Comparison of Ribosome Structure in Bacteria, Eukaryotes, and the Mitochondria (of a cow)|
|Bacterial (70S)||Eukaryotic (80S)||Mitochondrial (55S)|
(1 of each)
|23S (2904 nts)||25S (4700 nts)||16S (1560 nts)|
|5S (120 nts)||5S (120 nts)|
|5.8S (160 nts)|
|rRNA||16S (1542 nts)||18S (1900 nts)||12S (950 nts)|
But despite these differences, the basic operations of bacterial, eukaryotic, and mitochondrial ribosomes are very similar.