Wednesday, August 26, 2009

Ribosome More Complicated Than Thought

The ribosome is the molecular machine that assembles proteins. The assembly instructions (which amino acids to use) are stored in the DNA genes. A vast regulatory process selects the proper gene and a copying machine creates a copy of the DNA gene. The copy goes through some processing and is then passed to the ribosome, which obtains the appropriate amino acids, in the right order, and glues them together to form the protein backbone. This translation from DNA-copy to amino acid is done according to a code--the famed DNA code.

It is interesting that while the ribosome is the cell's protein assembly plant, the ribosome itself is made of many proteins. How did evolution create this protein factory? The blind process would have needed proteins to build the factory, but from where could it get proteins if the protein factory was not yet built. Evolutionists aren't yet sure just how this occurred.

Another problem is that the ribosome is complex, and new research is revealing it to be even more complex than previously thought. As one researcher explained:

Scientists used to think that the ribosome made a simple two-stage ratcheting motion by rotating back and forth as it interacts with mRNA and tRNA. What we captured were images of the ribosome in intermediate stages between the rotations, showing that there are at least four steps in this ratcheting mechanism.

We suspect that the ribosome changes its conformation in so many steps to allow it to interact with relatively big tRNAs while keeping the two segments of the ribosome from flying apart. It's much more complicated than the simple ratcheting mechanism in a socket wrench.

If evolution weren't a fact one might wonder if it really is the essential, unifying idea upon which all of biology depends.

1 comment:

  1. You ask how evolution could have built a protein making factory before there were proteins, and state that evolutionists are not sure how this occurred. Actually, scientists have a very good idea how this occurred. It is called the RNA World Hypothesis, and the ribosome itself shows how this world could have existed. It turns out that the ribosome's functional sites are not made up of protein, but rather of RNA. A ribosome can be stripped of all protein, and peptide bond formation is still catalyzed by the RNA. A primative RNA only ribosome most likely made the first proteins.