More on Ribosomes

I posted a blog entry about ribosomes at Telic Thoughts this week and since then came across an article entitled 'Protein Factory Reveals Its Secrets' at Chemical & Engineering News. The article is well written and contains some colorful illustrations. I like this quote:

"If genomic DNA is the cell's planning authority, then the ribosome is its factory, churning out the proteins of life.

It's a huge complex of protein and RNA with a practical and life-affirming purpose-catalyzing protein synthesis."

The following tidbit would have been a good fit for the TT blog entry which focused on the origin of ribosomes.

"Bacterial cells typically contain tens of thousands of ribosomes, and eukaryotic cells can contain hundreds of thousands or even a few million of them. The ribosome found in the bacterium Escherichia coli is made up of three RNA components and more than 50 proteins. It weighs about 2.5 million daltons. Eukaryotic versions have four RNAs and about 80 proteins and weigh about 4 MDa."

Not only is one left wondering how protein synthesis would have taken place before the advent of ribosomes, it is also curious how these heavyweights, composed of multiple proteins and RNA, would have evolved incrementally in accordance with natural selection.