Microsoft Word Kurzweil, Ray The Singularity Is Near doc

Upgrading the Cell Nucleus with a Nanocomputer and Nanobot.
Here's a conceptually simple proposal to 
overcome all biological pathogens except for prions (self-replicating pathological proteins). With the advent of full-
scale nanotechnology in the 2020s we will have the potential to replace biology's genetic-information repository in the 
cell nucleus with a nanoengineered system that would maintain the genetic code and simulate the actions of RNA, the 
ribosome, and other elements of the computer in biology's assembler. A nanocomputer would maintain the genetic 
code and implement the gene-expression algorithms. A nanobot would then construct the amino-acid sequences for the 
expressed genes. 
There would be significant benefits in adopting such a mechanism. We could eliminate the accumulation of DNA 
transcription errors, one major source of the aging process. We could introduce DNA changes to essentially reprogram 
our genes (something we'll be able to do long before this scenario, using gene-therapy techniques). We would also be 
able to defeat biological pathogens (bacteria, viruses, and cancer cells) by blocking any unwanted replication of 
genetic information. 
With such a nanoengineered system the recommended broadcast architecture would enable us to turn off 
unwanted replication, thereby defeating cancer, autoimmune reactions, and other disease processes. Although most of 

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these disease processes will already have been vanquished by the biotechnology methods described in the previous 
section, reengineering the computer of life using nanotechnology could eliminate any remaining obstacles and create a 
level of durability and flexibility that goes beyond the inherent capabilities of biology. 
The robot arm tip would use the ribosome's ability to implement enzymatic reactions to break off an individual 
amino acid, each of which is bound to a specific tRNA, and to connect it to its adjoining amino acid using a peptide 
bond. Thus, such a system could utilize portions of the ribosome itself, since this biological machine is capable of 
constructing the requisite string of amino acids. 
However, the goal of molecular manufacturing is not merely to replicate the molecular-assembly capabilities of 
biology. Biological systems are limited to building systems from protein, which has profound limitations in strength 
and speed. Although biological proteins are three-dimensional, biology is restricted to that class of chemicals that can 
be folded from a one-dimensional string of amino acids. Nanobots built from diamondoid gears and rotors can also be 
thousands of times faster and stronger than biological cells. 
The comparison is even more dramatic with regard to computation: the switching speed of nanotube-based 
computation would be millions of times faster than the extremely slow transaction speed of the electrochemical 
switching used in mammalian interneuronal connections. 
The concept of a diamondoid assembler described above uses a consistent input material (for construction and 
fuel), which represents one of several protections against molecular-scale replication of robots in an uncontrolled 
fashion in the outside world. Biology's replication robot, the ribosome, also requires carefully controlled source and 
fuel materials, which are provided by our digestive system. AB nanobased replicators become more sophisticated, 
more capable of extracting carbon atoms and carbon-based molecular fragments from less well-controlled source 
materials, and able to operate outside of controlled replicator enclosures such as in the biological world, they will have 
the potential to present a grave threat to that world. This is particularly true in view of the vastly greater strength and 
speed of nanobased replicators over any biological system. That ability is, of course, the source of great controversy, 
which I discuss in chapter 8. 
In the decade since publication of Drexler's