Does the second strand of a gene do anything?

Question

I know that a gene makes a protein by unraveling itself, and one of the strands assembles an RNA complement, which goes to the ribosome to be translated into amino acids. But (1) which strand does this? and (2) what does the other strand do?

Answer 1

The two strands are complementary. So, if there is an A on one strand, then the other strand has a T. The two strands are not identical, and indeed only one of the strands makes "sense" and is decoded to make protoeins, and is therefore known as the sense strand. The other strand is known as the "anti-sense" strand, because the nucleotide sequences on the anti-sense makes no sense to the cell. having two strands has its benefits. For example, when DNA is duplicated, the two strands unzip from one another, and different complementary strands can be added easily to each strand to come up with two identical DNA double helix strands. While the anti-sense strand is not involved in the manufacture of proteins, it is there to make DNA replication a lot easier.



Both RNA and DNA can be double stranded. The difference between the two is their different sugars. DNA has a deoxy-ribose and RNA has a ribose in their backbone. The differences in the sugars allow DNA to form the famous helical structure, making it much more stable than RNA if the strands are long. It is one reason why DNA is used to encode genes instead of RNA.

Answer 2

Randy may have misunderstood the question, or maybe I have.

But, from what I understand you are wondering why DNA has two strands? Since one strand is used by RNA polymerase II (an enzyme) to make RNA, but what is the other strand for?



Basically, DNA as a single strand is very unstable, you have to see DNA as 2 strands of sticky tape stuck together, as a whole they are pretty stable, but one strand of sellotape soon becomes knotted up & loops on it's self.



That is the reason, if DNA only had 1 strand, the template strand, the one used for RNA transcription, it would be unstable, and susceptible to mutations, damage...



But DNA is a double helix shape, the template strand, stuck to a complementary coding strand, for stability.



Take a look :

http://www.chemguide.co.uk/organicprops/aminoacids/transcribe2.gif



So one strand is for transcription into RNA, that will then be translated by the ribosome into AA's.. This strand is the template strand.



The other strand, the coding strand, is there more for the stability of the structure, and, of course, for DNA semi-conservative replication.



Hope this helps !

George

Answer 3

Genes are found on both strands. The two strands are usually called "Watson" and "Crick" by biologists, because we have wacky senses of humor like that. So some genes are transcribed from the Watson strand, and other genes are transcribed from the Crick strand in the other direction.