Question

what is difference between tRNA, mRNA and rRNA

Answer 1

all both have different struture as well as different functions.
but they all are types of rna..

Answer 2

That's an excellent question. I would be remiss to talk about nucleic acids and only talk about DNA. RNA is, in fact, the second of the two types of nucleic acids; however, there are a number of structural differences between the two.

First let's address the name. Like DNA, RNA is a nucleic acid composed of a sugar, a phosphate group and a nitrogenous base. One difference between DNA and RNA is the sugar. Whereas the sugar in DNA is deoxyribose, the sugar in RNA is ribose. Now, I won't dwell on the exact chemical difference between the two sugars, but ribose has one extra hydroxyl group compared to deoxyribose.

Second, there are four different nitrogenous bases found in DNA and RNA; however, there is one difference. The bases found in DNA are guanine, cytosine, adenine, and thymine. The bases found in RNA are guanine, cytosine, adenine, and uracil. Uracil forms two hydrogen bonds with adenine and functions just like thymine does. It's simply used in RNA instead of thymine.

Finally, unlike DNA, which is double-stranded, RNA is single-stranded.