Why is DNA antiparallel? Can it be parallel?
My biology textbook mentions that DNA is antiparallel and it got me wondering... Can DNA be parallel? What would happen if it was parallel? could DNA still replicate right?
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3 Answers By Expert Tutors
Jesse E. answered • 06/11/19
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Masters in Chemistry and Bachelors in Biology
In antiparallel DNA, one strand runs from 5´ to 3´ prime and the other strand runs form 3´ to 5 ´. This configuration allows the DNA strands to form complementary pair their nucleotides using hydrogen bonds. This configuration allows for the enymes of DNA replication to function.
If the DNA strand was parallel, replication would not be possible. The nucleotides would not be complementary to each other and, as a result, would not pair in a genetic molecule. Therefore, the DNA being antiparallel is the only way replication and life could occur.
Hillarie W.
In this case replication is completed because the DNA polymerase only goes 5 to 3 so on the lagging strand it has to be placed multiple times to form seperate Okazaki fragments. Since you're the professional, I suppose my question would be wouldn't it be possible and more practical for both to be running 5 to 3 parallel to each other? Then the polymerase would be able to just go all the way down each strand. I am aware of the current model the bases are complimentary so that is obviously a funtion that is necessary. My Real question is what is the main FUNCTION of them running opposite ways? Is it for Universal Law what goes up must come down or for communication purposes? Life as we know it seems to run this way so I was just wondering if there was some deeper symbology or meaning to them running opposite directions. I suppose I always believe they ran upward just winding around each other, so when I learned they ran opposite ways this got my gears turning so I am curious to hear your thoughts there.
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03/06/22
Lauren H. answered • 03/16/19
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From the Internet:
Antiparallel: A term applied to two molecules that are side by side but run in opposite directions. The two strands of DNA are antiparallel. The head of one strand is always laid against the tail of the other strand of DNA.
The molecule is constructed in this manner so that each nucleotide has an opposite match (G with C and A with T). This allows for the translation into mRNA which carries the "code" of triplets out into the cytoplasm to serve as a template for protein production.
Harsha D. answered • 03/14/19
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DNA has to be antiparallel. The antiparallel nature allows two strands to go in opposite direction. Which ultimately facilitate forming daughter DNA into two different directions and preety helpful during polymerase chain reaction that amplify DNA to make multiple copies of it.
if two strands of DNA were parallel there will not be any replication bubble as there is no leading strand and lagging strand ( both strands will be leading strands).
Mostafa S.
But why is having two leading strands impractical?
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04/21/22
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Jan B.
Parallel strands actually exist! I was surprised when i found out. Of course they cannot function as a main gene carrying DNA because replication would be problematic, however they may have some role. Maybe you'll find some insight in this publication https://doi.org/10.1111/febs.1418705/14/22