DNA

[BARRY J MARGULIES]

In article <2n88re$q8v at news.scri.fsu.edu>,
Avesha Jain <ajain at dirac.scri.fsu.edu> wrote:
>In article <2mj80q$c5g at eis.calstate.edu> dlevins at eis.calstate.edu (David Levinson) writes:
>>
>>--
>> Hi,
>>   I have a few questions that I need answers to URGENTLY regarding DNA. 
>>1) My teacher told me that DNA only produces proteins, and I always 
>>thought that it created the WHOLE body and was the design. What is the
>>truth?
>>2) I know about DNA replication, but can someone go into the process a little
>>further and explain DNA and RNA?
>>3) I have been told that DNA is the same in ALL species of organisms, if this
>>is true, why can't we replicate or change an organism yet?
>>   Overall, can someone explain what DNA really does, and is? Thanks! 
>>David Levinson

>Well, I'll try to answer #2. In DNA replication, an enzyme (called
>a restriction enzyme I think) separates the two strands of DNA. New
>nucleotides pair with those of the original strand. These nucelotides
>also bring along extra phosphates.
(diagram and explanation deleted)

I'm sorry, Mr. Jain, but restriction enzymes are far from the answer.  
The enzyme for which you search is called DNA polymerase, and it 
specifically adds nucleotide triphosphates to an extending complementary 
strand (the "copy" of the first strand) of DNA during the replication 
process.  There are actually a number of proteins involved in 
replication; some help in opening the double-stranded DNA complex; some 
help in adding the new nucleotides; some help in unwinding and rewinding 
the helix, etcetera.  It would be one wonderous enzyme that could do all 
that by itself.

To answer the original questions would take many a page, so I would direct 
you to textbooks, especially Watson. et. al., Molecular Biology of the 
Gene.  If that's too complex, then try examining Keeton's Biological 
Science; this should answer all your questions on a basic level, as well 
as help you figure out the discrepancies stated above.

-- 
-Barry (bjmarg at welchlink.welch.jhu.edu)