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What are the differences between 70s and 80s ribosomes?
Posted February 2, 2023
Answer
70S and 80S refer to the sedimentation coefficients of ribosomes in Svedberg units.
Basis of differentiation | 70S Ribosomes | 80S Ribosomes |
Definition | Are smaller ribosomes found in prokaryotes such as bacteria and also in eukaryotic cells | Are larger ribosomes that occur exclusively in eukaryotes |
Occurrence in the Cell | Found in free states in the cytoplasm of prokaryotes and in eukaryotic cell organelles such as mitochondria and chloroplast | Found in the cytoplasm or attached to the Endoplasmic reticulum in eukaryotic cells |
Sedimentation Coefficient | 70 | 80 |
Synthesis | Synthesized in the cell cytoplasm of prokaryotes | Synthesized in the cell nucleolus of eukaryotes |
Size | Smaller than 80S ribosomes | Larger than 70S ribosomes |
Type | Are mostly free-floating | May be free-floating or membrane-bound |
Subunits | Smaller subunit is 30S and larger subunit is 50S | Smaller subunit is 40S and larger subunit is 60S |
Components of larger subunit | 5-S rRNA, 23-S rRNA and about 34 proteins | 5-S rRNA, 5.8-S rRNA, 28-S rRNA and about 40 proteins |
Components of smaller subunit | 16-S rRNA and about 21 proteins | 18-S rRNA and about 33 proteins |
Number of RNA molecules | 3 RNA molecules | 4 RNA molecules |
Molecular Weight | 2.7-3.0 million Daltons | 4.0-4.5 million Daltons |
Number of Amino Acids | Around 8,000 | Around 16,000 |
Number of ribosomal proteins | 55 protein molecules, with 34 in larger subunit and 21 in smaller subunit | 73 protein molecules, with 40 in larger subunit and 33 in smaller subunit |
RNA-to-Protein ratio | 2:1 (more RNA) | 1:1 (equal amount) |
Influence of Antibiotics | Protein synthesis is inhibited by antibiotics | Protein synthesis is not inhibited by antibiotics |