DNA stands for deoxyribonucleic acid, while RNA is ribonucleic acid. Although DNA and RNA both carry genetic information, there are quite a few differences between them. This is a comparison of the differences between DNA versus RNA, including a quick summary and a detailed table of the differences.
SUMMARY OF DIFFERENCES BETWEEN DNA AND RNA
- DNA contains the sugar deoxyribose, while RNA contains the sugar ribose. The only difference between ribose and deoxyribose is that ribose has one more -OH group than deoxyribose, which has -H attached to the second (2′) carbon in the ring.
- DNA is a double-stranded molecule while RNA is a single stranded molecule.
- DNA is stable under alkaline conditions while RNA is not stable.
- DNA and RNA perform different functions in humans. DNA is responsible for storing and transferring genetic informationwhile RNA directly codes for amino acids and as acts as a messenger between DNA and ribosomes to make proteins.
- DNA and RNAbase pairing is slightly different since DNA uses the bases adenine, thymine, cytosine, and guanine; RNA uses adenine, uracil, cytosine, and guanine. Uracil differs from thymine in that it lacks a methyl group on its ring.
DNA provides living organisms with guidelines—genetic information in chromosomal DNA—that help determine the nature of an organism’s biology, how it will look and function, based on information passed down from former generations through reproduction. The slow, steady changes found in DNA over time, known as mutations, which can be destructive, neutral, or beneficial to an organism, are at the core of the theory of evolution.
Genes are found in small segments of long DNA strands; humans have around 19,000 genes. The detailed instructions found in genes—determined by how nucleobases in DNA are ordered—are responsible for both the big and small differences between different living organisms and even among similar living organisms. The genetic information in DNA is what makes plants look like plants, dogs look like dogs, and humans look like humans; it is also what prevents different species from producing offspring (their DNA will not match up to form new, healthy life). Genetic DNA is what causes some people to have curly, black hair and others to have straight, blond hair, and what makes identical twins look so similar. (See also Genotype vs Phenotype.)
RNA has several different functions that, though all interconnected, vary slightly depending on the type. There are three main types of RNA:
- Messenger RNA (mRNA)transcribes genetic information from the DNA found in a cell’s nucleus, and then carries this information to the cell’s cytoplasm and ribosome.
- Transfer RNA (tRNA)is found in a cell’s cytoplasm and is closely related to mRNA as its helper. tRNA literally transfers amino acids, the core components of proteins, to the mRNA in a ribosome.
- Ribosomal RNA (rRNA)is found in a cell’s cytoplasm. In the ribosome, it takes mRNA and tRNA and translates the information they provide. From this information, it “learns” whether it should create, or synthesize, a polypeptide or protein.
DNA’s genes are expressed, or manifested, through the proteins that its nucleotides produce with the help of RNA. Traits (phenotypes) come from which proteins are made and which are switched on or off. The information found in DNA determines which traits are to be created, activated, or deactivated, while the various forms of RNA do the work.
One hypothesis suggests that RNA existed before DNA and that DNA was a mutation of RNA. The video below discusses this hypothesis in greater depth.