Role of RNA Molecules: Definition & Functions

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  • 0:00 What Is RNA?
  • 1:06 Main Function of RNA
  • 2:45 Other Functions of RNA
  • 4:03 Lesson Summary
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Instructor: Julie Zundel

Julie has taught high school Zoology, Biology, Physical Science and Chem Tech. She has a Bachelor of Science in Biology and a Master of Education.

DNA gets all of the glory, but RNA is equally important. This lesson will examine RNA's role in protein synthesis, as well as its ability to act as an enzyme.

What Is RNA?

You've probably heard of DNA, right? Yep, DNA, or deoxyribonucleic acid, gets all of the glory. It is the blueprint for life, after all. I mean, it holds all of the information to build and maintain you! But what about RNA, or ribonucleic acid? RNA is actually quite a bit like DNA and is equally important.

So what are the differences between the two? Although they are both made up of a phosphate group, a five-carbon sugar and nitrogenous bases, DNA is double stranded whereas RNA is single stranded. The five-carbon sugar in DNA is called deoxyribose and the five-carbon sugar in RNA is called ribose, which is how they get their different names. Both RNA and DNA have the bases adenine, guanine and cytosine, but DNA's fourth base is thymine and RNA's is uracil.

Main Function of RNA

Now that you know what RNA is made up of, let's spend some time discussing the function of it in your body. There are actually three types of RNA: messenger RNA, ribosomal RNA, and transfer RNA. Let's begin with messenger RNA, or mRNA, which is a copy of a section of DNA. During protein synthesis, or the making of proteins, a section of DNA is copied through a process called transcription. So, why bother copying the DNA? Well, DNA needs to remain in the nucleus for safekeeping, but since it is the blueprint your body still needs the information it holds. Instead of taking the blueprint out of the nucleus where it can get harmed, your body makes a copy of it.

This copy, the mRNA, then leaves the nucleus of the cell and undergoes translation, which means the mRNA is read and the correct ingredients are gathered to make the proteins, which are needed for all sorts of things, from the hemoglobin that carries oxygen in your blood to the keratin that makes your fingernails.

The mRNA then heads towards a ribosome, which is a structure inside of the cell. Ribosomal RNA (rRNA), moves along the mRNA and helps build the protein. Transfer RNA (tRNA), is found on the ends of the amino acids, and it brings the correct amino acid to the ribosome.

To help you better grasp this rather complex terminology, think of mRNA as a recipe and tRNA as a grocery-getter who fetches all of the ingredients for the recipe, with rRNA being the chef who mixes all the ingredients in the right order.

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