Sense Strand and Antisense Strand – What is the Difference?
Do you guys get confused between the terms sense and antisense strand or what is coding and non-coding strand, which is plus and minus strand? Is it the template or non-template strand? Well, then get ready to clear your doubts and have crystal clear concept about these terms.
Let’s start with template strand and non-template strand because I am sure we are all familiar with these two terms for sure. DNA is double stranded which has one strand running in 5’->3’ direction and other one in 3’->5’ direction.
- Template strand and Non-template strand –
Template strand is the strand of DNA which serves as template to give the mRNA which means it is the strand that is going to get transcribed to mRNA. Now RNA polymerase which synthesizes mRNA can read the DNA in 3’->5’ direction (newly synthesized mRNA is in 5’->3’ direction) so this means the 3’->5’ direction DNA strand is the template strand. If 3’->5’ direction is template strand clearly the opposite strand i.e. 5’->3’ direction is non-template strand.
- Sense strand and Antisense strand –
Now look at the newly formed mRNA (5’->3’ direction), it is the copy of non-template strand (because it is transcribed from the template strand which is complementary to non-template strand). The only difference would be mRNA would have uracil instead of thymine. So by looking at non-template strand we can actually predict what would be the expected mRNA and thus the 5’->3’ direction strand is called sense strand. This is one point I use to get confused. Sense doesn’t mean it is going to get transcribed but it just means it makes sense, when we read it we know the expected mRNA J and of course the other strand (3’->5’ direction) is called antisense strand.
- Coding strand and Non-coding strand –
When we read the 5’->3’ direction strand or which is also called sense or non-template strand as we saw above, it gives us the expected codon sequence we would get in mRNA right? That means we can predict all the codons from the 5’->3’ direction strand and because of this it is called coding strand and the other strand is called non-coding strand (because it doesn’t show us codon sequence).
- Plus strand and Minus strand –
When we read mRNA (5’->3’ direction), it is going to be the same as codon strand (5’->3’ direction) and because they both are running in same direction having the same nucleotides (only difference is of uracil in mRNA instead of thymine) it is called the plus strand. The other strand is called minus strand.
I hope this helped 🙂
Watch this video to understand this topic more in details.
