DNA Repairs

Good. I'm glad this isn't homework. Otherwise,
Holy Grail - Wikipedia, the free encyclopediaStart here<

Surprisingly good places to start, even given the complexity of the subject.

http://en.wikipedia.org/wiki/DNA

http://en.wikipedia.org/wiki/DNA_repair

No shrubbery required.

http://en.wikipedia.org/wiki/Monty_Python_and_the_Holy_Grail

Yes, every cell has its own service shop, making repairs as needed. They also have their own self-destruct mechanism if the damage is too great (dead skin after sun-burn).

What happens when you through some prions in the mix.

If you talk to some radiation biologists you will come across two sets of beliefs. One is the Linear No Threshold LNT theory that says all radiation is dangerous and the effect upon the body is a linear function of the dose received and there is no threshold at which radiation dosages are harmless.

The other school believes in a concept called hormesis, There is a DNA repair mechanism in the cell which repairs radiation damage to the DNA unless the damage was so severe that that it couldn't be repaired in which case the individual cell is killed before it has a chance to mutate into a malignant cell. Those who believe in hormesis also recognize that a sufficiently large dose of radiation will cause radiation sickness followed by death.

Yuval and Smeaton answered the question, the DNA repair enzymes are produced in the cell. There are many enzymes and many mechanisms for DNA repair - they are still discovering new ones. All of this takes place in the cell (pick a cell, any cell).

As for the Grail, it has been next to mein the sky for millenia, and the subject of varied legends pointed out by Lyn, including the delightful tale of Bran's Cauldron (most relevant to the subject matter of your question), the deep meaning of which is best contemplated while listening to the sound of coconut shells (somewhat hairy natural grails) clacked together in a low budget comedy (see Jack, above).

It may also be worth mentioning, that enzymes active in the repair of genetic material strands, are activated and suppressed by what's commonly recognized and called "Control-Genes" - in a complex chemical multi-gene interaction, not yet fully understood.

Much of what was previously thought to be "Junk DNA" is now vaguely understood as "Functioning Matter" and today is suspected to play critical (yet under-appreciated) role in "Structural Chemistry" and even more important, in gene-interaction of genes controlling the activation and suppression of other genes, hence their title as "Control-Genes"