RNA

RNA is a large, complex molecule (macromolecule) that functions alongside DNA to help cells make proteins.

DNA is a macromolecule that allows cells to function and carries the genetic code that determines the traits of a living organism. Among other things, RNA works with DNA to make proteins, which are required for many essential functions within living things. During this process, RNA acts as a kind of copy of the DNA that carries its genetic information outside of the cell nucleus.

RNA also carries the genetic information of many viruses.

RNA stands for ribonucleic acid. Like DNA, RNA is a nucleic acid, which means it is made of a phosphate, a sugar, and nitrogen bases.

RNA consists of one long strand of sugars and phosphates and the nitrogen bases, which form base pairs. The result resembles a ladder with just one side. By comparison, DNA has two long strands of sugars and phosphates, with the base pairs between them, making it look like a spiraled ladder (a double helix). RNA has three of the same nitrogen bases found in DNA—adenine (A), guanine (G), and cytosine (C). Instead of thymine (T), though, RNA has uracil (U).

DNA contains the instructions that cells need to make proteins. An enzyme in the cell nucleus, known as RNA polymerase, unspirals the DNA and breaks the ladder in half down the middle. The enzyme then reads the nitrogen bases (the rungs of the ladder) and makes RNA in a process known as transcription. The RNA sequence matches the sequence from the DNA strand except that in RNA, adenine is paired with uracil instead of thymine, and the sugar deoxyribose is substituted with ribose.

There are three major kinds of RNA. Messenger RNA (mRNA) is created from a DNA template in the nucleus and then carries the genetic code to structures called ribosomes in the cytoplasm (the middle layer of the cell between the nucleus and the membrane), where it specifies the amino acid sequence for protein synthesis. Ribosomal RNA (rRNA) is a part of ribosomes that allows messenger RNA to function. Transfer RNA (tRNA) transports specific amino acids to ribosomes during protein synthesis.

We took a microscopic look at the differences between RNA, mRNA, and DNA, and their vital roles. Read all about it here!

DNA and RNA are ancient, but their discovery was relatively recent. In 1869, chemist Friedrich Miescher documented a kind of molecule that had never been studied before—nucleic acid. It wasn’t until around the 1930s that the term DNA began to be used, with RNA following in the 1940s. In the 1950s, the work of biophysicist Rosalind Franklin and biologists James Watson and Francis Crick revealed DNA’s double helix structure. The function of RNA began to be further understood during the 1950s and 60s as scientists began to understand the role of messenger RNA.

This understanding is still developing. Until quite recently, RNA’s role was thought to be largely limited to assisting with protein synthesis in its forms as messenger RNA, transfer RNA, and ribosomal RNA. However, scientists are continuing to discover new types of RNA and more functions that RNA performs in the body. For example, recent discoveries suggest that there are several types of RNA that regulate how many proteins the ribosomes produce.

Some viruses completely lack DNA and instead their genetic information is contained entirely within RNA. COVID-19 is this type of virus, known as an RNA virus. RNA viruses are more adaptable and are much more likely to mutate than DNA viruses.

Unlike DNA, which takes the form of a double helix, RNA consists of a single strand, as pictured in this illustration.

Getty. Ribonucleic acid (RNA) chain.

Most biology students learn about RNA alongside DNA. Our understanding of the role of RNA within the cell is still expanding.

A new single cell #RNA and BCR sequencing study of human tonsils improves our understanding of B cell maturation, providing an expansive resource for researchers to study B cell responses during #health and disease.

From @SciImmunology: https://t.co/UNePQcNCth pic.twitter.com/kPcXGCSCAV

— Science Magazine (@ScienceMagazine) February 20, 2021

The messenger RNA technology that developed successful covid-19 vaccines could transform medicine. Next up: sickle cell, HIV, and malaria. https://t.co/xWbyr9cplh

— MIT Technology Review (@techreview) February 20, 2021

• DNA
• RNA polymerase
• messenger RNA
• transfer RNA
• ribosomal RNA
• RNA virus
• transcription
• protein
• protein synthesis
• enzyme
• ribosome

True or False?

One of RNA’s main functions is using the information from DNA in the creation of proteins.