The other side of DNA?

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CurlyQe
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The other side of DNA?

Post by CurlyQe » Fri Jul 21, 2006 12:57 am

This isn't anything new or anything, but I've noticedthe trend of effeciency in every function a cell does in my highschool biology class. We've also recently discussed how RNA codes from DNA from the master strand of the DNA. My question is: if everything in a cell depends of effeciency, then what does the other strand of DNA do, or the "nonsense strand" if it doesnt help in RNA reproduction? Wouldn't it make more sense if BOTH strands helped RNA production?

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Post by Mjhavok » Fri Jul 21, 2006 1:42 am

In DNA replication both strands replicate but in different ways. In RNA replication only the 1 strand is needed as RNA is single stranded mostly.
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Post by CurlyQe » Fri Jul 21, 2006 2:26 am

Thanks for taking time to respond!

hmm, in RNA replication, wouldn't it make more sense that both sides of the DNA participate in RNA production? Ya know, instead of making only ONE strand of RNA, it could possibly make two and produce proteins twice as fast. Shouldn't the nonsense strand be doing SOMETHING? or is there something preventing both sides of the DNA to be used in RNA production? Can the cell not handle the information if the nonsense and master strand are used?

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Post by canalon » Fri Jul 21, 2006 3:11 am

Well transcibing and reverting the other strand would very energy and time consuming, not sure it would improve the enrgetic output of the cell. And anyway, I am not really sure that there is such a need of mRNA production.

The second strand is not useless though, if you consider its role in stability and replication of DNA.
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Post by his-tone » Fri Jul 21, 2006 6:30 am

budddy. i think both strands are being used during transcription also. the difference is inthe promoter orientation.

try searchin the web or a gud mole bio text fot these basics.

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Post by CurlyQe » Fri Jul 21, 2006 7:55 pm

Thats the thing, I can't find it in my textbook nor the internet. From other people's posts I get the idea that it's just too much energy to handle or produce. I'm just a highschooler, but and it would be much appretiated if if you can explain why the promoter orientation matters?. I have exhausted my other recources, that is why I'm here.

But thanks to those who have tried to answer my questions! I think I have the gist.. do I?

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Re: The other side of DNA?

Post by sdekivit » Fri Jul 21, 2006 8:04 pm

CurlyQe wrote:This isn't anything new or anything, but I've noticedthe trend of effeciency in every function a cell does in my highschool biology class. We've also recently discussed how RNA codes from DNA from the master strand of the DNA. My question is: if everything in a cell depends of effeciency, then what does the other strand of DNA do, or the "nonsense strand" if it doesnt help in RNA reproduction? Wouldn't it make more sense if BOTH strands helped RNA production?


it's just the term non-sense strand during transcription, but both strand contain genes that can be stranscribed. It's not so that 1 strand contains all the genes and the other is useless.

--> the fact that genes are located in both strands makes regulation of gene-expression possible. When for example 1 gene is transcribed and in this region another gene lays on the other strand (thus the non sense strand) it is only possible to transcribe this gene when the other is being transcribed.

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Post by mkwaje » Sat Jul 22, 2006 12:07 pm

I believe the "sense" strands contain the needed gene codes to be used in transcription (production of mRNA). The other strand is complementary to the sense strand and thus could not code for the same mRNA that is needed. Remember A-T, C-G sequences.

If the sense strand goes like:

ATCGATCGATCG

then the mRNA equivalent is

ATCGATCGATCG <--- sense strand
UAGCUAGCUAGC <----mRNA (to translate into protein)

If you want to use the anti-sense, then the base sequence will be complementary to the "sense" strand:

TAGCTAGCTAGC

thus a different mRNA sill be produced from this sequence and before I forget, the 5' to 3' transcrition rule will also be followed inverting the sequence making it totally useless in transcribing the correct mRNA sequence.

But it does help in DNA stability, can you imagine if your DNA is single stranded? It would be very very unstable esp. in long sequences.

And to my knowledge, the opposite strand of the "sense" strand is not "non sense" strand but the "anti sense" strand. The nonsense codons are the sequences that codes for the terminal amino acids or sometimes the nonsense genes are referred to as the genes that doesn't code for anything (this include the introns) also termed as junk DNA. My apologies if I'm mistaken.

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Post by sdekivit » Sat Jul 22, 2006 2:58 pm

mkwaje wrote:I believe the "sense" strands contain the needed gene codes to be used in transcription (production of mRNA). The other strand is complementary to the sense strand and thus could not code for the same mRNA that is needed. Remember A-T, C-G sequences.



but this RNA-product from the anti-sense strand can be a product of a totally different gene with a complete other function ;)

It is not that black-white picture about there is 1 sense strand and 1 anti sense strand and the sense strand contains the genes and the antisense strand does not. The following does exist in the DNA:

-------|------gene x------|-----------------
------------ |gene y|----------------------

(between || is the length of the complete genes)

An example is the NF1-gene. in intron 26 of the sense strand of the NF1 gene the antisense strand contains three other genes transcribed from the antisense strand of the NF1 gene: OGMP, EVI2A and EVI2B

mkwaje wrote:If the sense strand goes like:

ATCGATCGATCG

then the mRNA equivalent is

ATCGATCGATCG <--- sense strand
UAGCUAGCUAGC <----mRNA (to translate into protein)


this is crap, recheck your books please.

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Post by CurlyQe » Sat Jul 22, 2006 4:09 pm

If the sense strand goes like:

ATCGATCGATCG

then the mRNA equivalent is

UAGCUAGCUAGC <--- mRNA strand
AUCGAUCGAUCG <----tRNA strand

sorry, it was driving me crazy
Last edited by CurlyQe on Sat Jul 22, 2006 4:45 pm, edited 1 time in total.
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Post by sdekivit » Sat Jul 22, 2006 4:17 pm

another example why this is such an important concept where many mistakes are made.

The sense strand is the coding strand. During translation the antisense strand is used as the template, so the mRNA has the same sequence as the coding or sense strand except thymine is replaced by uracil.

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Post by CurlyQe » Sat Jul 22, 2006 4:46 pm

Does the non sense strand have any genes coded into it that the sense strand does not?
"What can be asserted without evidence can also be dismissed without evidence." --Christopher Hitchens

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