From DNA to proteins

Ribonucleic acid, or RNA, is the cell’s ingenious system of transferring instructions from the DNA code to the rest of the cell. It’s a supercomputer download system and much more. Here’s a very very simple explanation of how it works.

The chromosome housing a section of gene to be copied is dragged over to the cell’s nuclear membrane by a molecular machine. Part of the chromosome super-coil is then unwound by another machine, exposing the exact section to be copied. More machines create a protective bubble over this section of DNA. The DNA is then split by another machine. More machines hold the DNA back from recoiling again. Another machine finds the exact spot in the DNA code that is to be copied.

A Transcribing machine collect spare nucleotide component molecules and match them with the exact three letter codons of the original master DNA code. The transcribing machine then spits out a copy of a short section of a new RNA molecule. More machines control the speed because the replication bubble is slower moving than the transcribing machine.

Short strands of daughter RNA code are released from the machine to be taken away and spliced together by other machines. The DNA is re-zipped by yet another machine and the chromosome dragged away from the nuclear pore. Still more machines proofread everything, making the copy as perfect as possible.

Splicing together short parts of the RNA cleverly enables 100,000 different proteins to be built from just 23,000 genes. Some parts of our DNA letter sequence can even be moved along several nucleotides or codons, read again and produce another perfect message for coding a different protein. The DNA molecule can even be read in each direction.

Once splicing and re-connection of the RNA molecule is complete, it is tagged by another machine for transport out of the nucleus. More machines place a cap at one end and a tail at the other end to stabilise the RNA becomes and protected from molecular garbage collecting machines. RNA is then moved by transporter machines out through a celln nucleus portal to a protein-based ribosome.

The conversion of RNA in the ribosome to amino acid chains is called translation, and for good reason. The procedure is like translating from English to Spanish and printing it off from a computer, all in real time.

Inside the ribosome, more machines find the exact codon to begin translation. As all of the codons of the RNA are read, other machines act like taxis, dragging in other machines, each of which houses a specific three-letter codon at one end and a specific amino acid at the other.

When the the three letter codon is matched perfectly at one end to an RNA codon, the amino acid at the far end is electrostatically released and bonds onto a growing chain of other amino acids. This “daisy chain” grows at about 3-5 amino acids per second. During this whole process many more separate proofreading systems ensure that there are no mistakes.

Once the amino acid chains are linked and completed inside the ribosome, most are then packed inside a “box” and taken by a transport machine to the Golji apparatus. Inside the Golji apparatus the amino acid chain is bent, shaped and moulded through four levels into incredibly complex protein molecular machines.

It is hereinside the Golji apparatus that the most complex protein machines will have carbohydrates and/or lipids added to form much of the essential molecular machinery of the cell. When this process is complete other machines take the completed proteins to the place in the cell where they start their 2-4 day working life as…machines!

The precise order of the amino acids determines the type of protein that will be built. It is this application of incredibly complex informational order to a dumb chemical object that creates the true building blocks of life. It is truly a miracle.

Conclusion

Where did this most complex and perfect code in the universe come from in the first place? No evolutionary scientist has an adequate theory as to how it originated. This is because the DNA code is essential for the production of machines, and the machines are essential for the DNA to be unpacked. It’s a classic chicken and egg dilemma. This conundrum has led to at least seven different theories as to how DNA originated. One researcher calls them all a “dreary, vicious circle” of dead-end concepts.

Bottom line: God made it and he is a genius!

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Kevin Davis