DNA Double Helix
DNA structure. The DNA structure is a double helix consisting of two complementary strands, the coding strand and the template strand. They differ only by a few properties and functions.
Coding (or non-template) strand. The coding strand is the DNA strand whose base sequence is similar to its primary transcript (RNA). This strand contains codons, while the non-coding strand contains anticodons. The coding strand serves as a template for producing complementary RNA.
Template strand. The term template strand refers to the DNA sequence that can duplicate itself during mRNA synthesis. The cell uses a non-coding/antisense DNA sequence as a template to produce mRNA.
| Difference between Coding and Template Strands |
| Coding Strand |
Template Strand |
| The coding strand determines the correct nucleotide sequence of mRNA. |
The template strand acts as a base for mRNA transcription. |
| It is also known as sense strand (plus strand) or coding strand. |
It is the antisense strand (minus strand) or a non-coding strand. |
| They do not take part in the transcription process. |
Here, they take part in the transcription. They help in the formation of mRNA. |
| The coding strand is directed in the 3’ to 5’ direction. |
The template strand is directed in the 5’ to 3’ direction. |
| The coding strand has a complementary nucleotide sequence. |
The template strand does not have any complementary sequence. |
Central dogma of molecular biology. Here it is: DNA codes for RNA and then RNA codes for proteins.
DNA is an informational storage molecule capable of replicating itself. DNA serves as a template for the direct synthesis of a messenger RNA (mRNA) molecule, in a process known as transcription. Secondly, mRNA is “read” at a ribosome by transfer RNAs (tRNAs), which work together to assemble a specific chain of amino acids, which collectively assemble to generate a protein, a process is known as translation.
Viral replication. The exception to this dogma is how viruses work, where the virus' DNA produces viral RNA which in turn synthesizes DNA. So, in this case, the information flow is from the virus' DNA-to-viral-RNA followed by viral-RNA-to-DNA. The other exception is RNA-to-RNA found in many viruses and eukaryotes.
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