There are many molecules that are involved in carrying, storing, and transporting genetic information. The most common of these is probably DNA. In addition to DNA, there is a category of molecules known as RNA. RNA is very similar to DNA in structure, but has different functions. There are several different types of RNA, two of which are mRNA and tRNA. There are important differences in structure and function between mRNA and tRNA.
Let’s start with mRNA. mRNA is an acronym for messenger ribonucleic acid. This is a complex chemical that helps a cell move information from the nucleus of the cell (where the DNA is stored) to the ribosome (where proteins are made). Here’s a bit on how that works. DNA stores information. This information involves how to make a variety of proteins. But DNA doesn’t make protein directly, there has to be a way to get the blueprints (DNA) to the factor (ribosomes). This is where mRNA comes in.
mRNA takes a sequence of information and takes it to a ribosome, where it will be further manipulated until a functional protein is made. mRNA is formed as a long strand, typically in a single helix (spiral) shape. The message is carried in groups of three neucleotides. A series of many nuceotides makes up an mRNA molecule. When they get to the ribosome, those three nucleotides (called a codon) code for a single amino acid. The process is a bit more complicated that this, but that’s the basic idea.
tRNA has a completely different structure and function. tRNA stands for transfer RNA. tRNA is a shorter strand of nucleotides, making it much smaller than mRNA. tRNA takes an amino acid and “transports” it to the newly made protein chain. The tRNA then helps attach the amino acid to the end of the new protein, adding to its structure. Thing of tRNA as something of a construction crane that moves parts in to the right position where they can be chemically welded to the new construction. Of course, that’s a somewhat crude analogy, but it’s really not much more than this, only on a very small scale.
While mRNA is a long spiral shaped chain, rRNA has a very different shape. tRNA is a significanlty smaller molecule, and is shaped more like a clover leaf. This shape is vital to it’s function. The shape of tRNA enables to to attach an amino acid to it in the right spot. When the tRNA gets to the protein that is under construction, its small size and specialized shape allow it to chemically bond the amino acid in the right position.
The actual chemical processes that are taking place during these events is far more complicated than what I’ve outlined. Also, in addition to mRNA and tRNA, there are other types of RNA. The construction of proteins from a DNA template is not simple. The differences between mRNA and tRNA enable them to have different functions in this process.
