Describe the shapes of the three types of RNA?

Question

Describe the shapes of the three types of RNA?

Answer 1

Like mRNA, the tRNA is made up of a series of nucleotides. Also, the tRNA molecule is made in much the same way as the mRNA molecule. The process of transcription means that the RNA molecule uses the sequence of nucleotides in the DNA molecule to determine its own structure. So you end up with a string of nucleotides - but this time much smaller. A mRNA molecule could be as big as 3000 nucleotides long, as there may be many amino acids to code for. However, a tRNA molecule isn't coding for loads of amino acids - only one amino acid is going to be bound to it. For this reason, it's much smaller - perhaps as much as 90 bases long.

Although the tRNA molecule is single stranded, parts of the molecule are made up of sequences of complimentary bases. Imagine that there are five adenosine nucleotides at one point in the molecule, and a bit further along, there are five uracil nucleotides. Well, in RNA, adenosine forms hydrogen bonds with uracil, so the molecule will loop round, with the complimentary bases binding to each other. This base pairing occurs extensively throughout the molecule, leading to a structure known as the 'three leafed clover' shape.

In a tRNA molecule, the extensive base pairing leads to this distinctive shape. The image shown on the right is obviously not what a real tRNA molecule would look like, but is a good way of representing its structure. The structure for a tRNA molecule is, in fact, very important, because it has two essential features. One has been implied already - the binding site of the amino acid which it is to bind to. The other is something called the anticodon.

Answer 2

mRNA is linear in shape like thread, rRNA is in the form of globular (ball like) structure with two sbunits joining to make one and tRNA is in the form of clover leaf structure.