What happens to a second strand of dna identical the first, if the first is irradiated by appropiate lasers?
155749
I'm not sure how you intend to destroy one strand and not the other while the are rapped around each other, but the two strands can be easily separated using naturally occuring rep enzymes.\n\nIf the appropriate enzymes and nucleotides are present, the missing strand will be replaced with a new, identical strand.  In the absence of the appropriate components, the single-stranded DNA will continue to exist for a while, but will slowly degrade as it is less stable than the double-stranded form.  Also, the DNA will likely fold up on itself as there are almost certainly numerous regions which are complimentary to each other.\n\n__________\nDo you mean identical strands or complementary strands?  If they're identical, they're not two halves of a double-stranded molecule, so what happens to one will have no relation to what happens to the other.  If you mean complementary, you could stand to be a bit clearer on what you expect the laser to do to the strand that is irradiated.
499512
that's when an outside influence, like radiation or a glitch in the copying during cell division or something causes a change in the chromosome-- making it no longer an exact copy of the original. most of the time it's harmless or destructive; in the first case, it can be passed on but changes nothing, and in the second, the cell usually aborts or dies before it causes trouble. sometimes you get a cancer. sometimes you get a neat new adaptation.
768977
Dispersive replication of DNA was a model of replication which has been proven wrong. If replication were dispersive, both strands of the parental DNA would be cut into small bits and new DNA would be synthesized to fill the gaps. This way, new DNA strands would contain an equal amount of old and newly sythesized DNA. After, say, 3 rounds of replication, the old DNA would be equally dispersed among the eight DNA molecules.\nJust remember that the actual form of replication in cells is the semi-conservative one.
925374
transcription in cells makes RNA copies of DNA.
575480
The double helical structure of DNA is due to hydrogen bonding between the base pairs, therefore non-covalent.\n\nEach strand of DNA is a chain of nucleotides. The atoms of each nucleotide are held together by covalent bonds.
865802
Your cells would split without first replicating and dividing your chromosomes.  This would be a major problem because equal copies of your DNA would not go to the correct cells.  This would be a serious mutation and would probably cause a serious illness or even death.
906596
Post Replication Repair Mechanism - DNA Repair\n\nThe reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions.  The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strands; photo reactivation repair, in which the lethal and mutagen effects of ultraviolet light are eliminated; and post -replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex.  Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.
618211
UV can affect DNA from any organism.  \n\nUV (ultraviolet) radiation is the high-energy non-visible radiation in sunlight, beyond the violet end of the visible spectrum (hence the name ultraviolet).  This high-energy radiation can knock DNA molecules out of whack ... what we call a mutation.  \n\nThe difference betwen bacteria (and other single-celled creatures) and multi-cellular creatures is that bacteria will pass this mutation on when they reproduce by division. \n\nIn multicellular organisms, this mutations in the DNA can cause uncontrolled growth of new cells, all with the same damaged DNA.  This is cancer.
128889
Here ya go!\n\nhttp://science.howstuffworks.com/laser.htm
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DOUBLE-STRANDED HELIX
808807
I guess that would depend on the strength of the radiation passed. But as Bilirubin is after all a protein, I guess its tertiary structure would get mutated by strong radiation like all other proteins !!!
533059
As the radioactive elements decay, they emit high-energy particles that go crashing through the cell(s). These particles hit atoms within the cell, creating either ions that go on to damage the cell's DNA, or they hit and directly damage the DNA. Once their DNA is damaged, cells usually either repair the damage, or if they can't, commit suicide (called apoptosis). Only those cells that have been damaged and fail to repair it and fail to commit suicide can become cancerous. Of course, the final requirement is that the DNA is damaged in an area that controls cell replication is such a way as to allow the unchecked proliferation of the cell.
341237
Light is absorbed by double bonds and as are more double bonds in double stranded DNA, more light is absorbed by the double bonds.\n\nThe double bonds are in the DNA bases.
341693
The mother and child will have *nearly* identical DNA.  There will be a few mutations because mutations are ubiquitous, but 99.99+% of their DNA will be the same.
1098660
Your question isn't easy to read, but i think i understand it enough. There is one mole of 1kbp DNA strand with an EcoR1 restriction site in the middle. The amount of 5'ends produced when you addd EcoR1 to the DNA will be double because you will be effectively cutting the DNA in half. I hope this is what you were asking
790485
I've answered a similar question in the past\n\nhttp://answers.yahoo.com/question/index;_ylt=ApDo1VHr18AJSQm6WOxC_8Dsy6IX?qid=20061028024332AAKbYkD\n\nor copy pasting...\n\n"The more bulky the molecule the harder it is for it to move through the gel pores and thus the slower it will run.\n\nThe order in a gel would be\ncircular nicked (so there is no supercoiling)\nlinear\nsupercoiled\n\nObviously from this order supercoiled is the fastest running, though sometimes it can run at the same height as linear.\n\nThe migration of linear DNA is the one representative of the actual size."
822273
Hi. DNA is a very simple structure that has a very complicated role. Free radicals (oxygen ions, for instance) can damage the DNA in a cell. It would require removal of the cell's DNA to do what you propose. May be better to neutralize free radicals in the first place.