December 8, 2021
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Dissimilarity of DNA and RNA

DNA and RNA are essential molecules in cell biology, and these molecules are responsible for the storage and interpretation of genetic...
Tomohiro Takano

While life is very diverse at the molecular level, it comprises the same building blocks – Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA and RNA are essential molecules in cell biology, and these molecules are responsible for the storage and interpretation of genetic information that bolsters all life.

They are both linear polymers, consisting of phosphates, sugars, and bases. But there are specific vital differences that separate them. These differences allow the two to work together and achieve their essential roles. Here is the crucial difference between DNA and RNA. But, before we go into the difference between the two, we take a look at what DNA and RNA are.

Defining DNA

1. DNA is responsible for storing all the hereditary materials of a cell.

2. It also has all the directives for synthesizing other molecules.

3. It is a polymer made of small molecules known as nucleotides. Each nucleotide has a phosphate group, nitrogenous base, and a 5-carbon sugar. The type of nitrogenous bases present in DNA molecules are:

   a. Adenine

   b. Thymine

   c. Guanine

   d. Cytosine  

The DNA molecules’ nucleotide sequence controls the instructions present in a stretched DNA. A string of nucleotides joined together to make a DNA strand. Each DNA molecule has 2 strands that twist around one another to form a double helix structure. The nucleotides are joined together by hydrogen bonds to make up a DNA strand. These bonds are formed between specific nitrogenous bases, referred to as base pairs. The base pairs in deoxyribonucleic acid include:

  • Adenine and Thymine
  • Cytosine and Guanine

Defining RNA

RNA is mainly found in the cytoplasm, while some may also be in the nucleus. Its job is to fulfill the encoded instructions in DNA. There are 3 types of RNA, each performing a different function.

  • Messenger RNA (mRNA): This type of RNA carries coding sequences for protein synthesis to the ribosomes.
  • Ribosomal RNA (rRNA) is the primary ribosome component that performs protein synthesis.
  • Transfer RNA (tRNA): this type of RNA carries amino acids to the ribosome, linked to proteins.

RNA comprises ribonucleotides containing a nucleotide base, a 5-carbon sugar, and a phosphate group.

There are 4 types of Nitrogenous bases in RNA molecules, which include:

- Adenine

- Uracil

- Guanine

- Cytosine

Similar to DNA molecules, RNA is united by phosphodiester bonds which link the 5’ carbon atom of one sugar molecule and the 3’ carbon atom of another sugar. However, unlike deoxyribonucleic acid, ribonucleic acid is a single-stranded molecule, though it can still be shaped into double-stranded structures. The base pairs are as follow:

  • Adenine and Uracil
  • Cytosine and Guanine

Here, we have identified the key areas where DNA and RNA differ:


DNA is the blueprint responsible for creating all biological life, and it encodes all genetic information. These functions are only in the short term. And in the long-term, DNA serves as storage that allows life blueprints to pass from one generation to another. On the other hand, RNA is a copy of DNA that is used to transfer the genetic code to the ribosomes from the nucleus to make proteins.


While the backbone of DNA and RNA comprises sugar, sugar in DNA is known as alternating sugar (deoxyribose) and ribose in RNA. The “deoxy” shows that DNA has only one hydroxyl (-OH) and alone hydrogen atom attached to its carbon backbone, while RNA has 2 hydroxyl groups attached. RNA’s extra hydroxyl group helps convert genetic code into mRNAs that can be changed to proteins. In contrast, deoxyribose sugar makes DNA more stable.


As earlier discussed, the bases present in DNA molecules are adenine, Thymine, Guanine, and cytosine. RNA also contains all these bases, except thymine bases. It replaces the base-pairing with uracil bases, which pair to adenine.


A DNA molecule is made up of a single chromosome composed of about 200 million nucleotide pairs, which is equal to about 2 inches in length. The RNA molecules formed from transcription separate from the parent DNA in a short strand form. Since they are copies of only a particular DNA region, RNAs are shorter than DNA, and RNAs are a few nucleotides long.


DNA is stored inside the nucleus, making it easier to transfer them. Few DNA is also present in the mitochondria. The 3 types of RNA can be found in different locations. The mRNA is found in the cytoplasm, the tRNA roams around the cytoplasm, and the rRNA is part of the ribosome.


DNA is an integral part of organisms, so it needs to be protected against changes like mutations or attacks. Proteins protect the DNA stored inside the nucleus. Plus, the molecule has many means of repair. RNA, in contrast, is more reactive than DNA. Besides, the single-strand structure makes RNA more vulnerable to enzyme attacks.

Ultraviolet Damage

The interaction of DNA or RNA with UV radiation leads to the creation of photo-products. Pyrimidine dimers are the essential photo-products, and they are formed from cytosine or thymine bases in DNA and cytosines or uracil in RNA. Ultraviolet induces the creation of covalent linkages between a series of bases. Proteins and DNA are the major targets of ultraviolet medicated cellular damage because of the ultraviolet absorption characteristics and abundance in the cells. Overall, DNA is more vulnerable to UV radiation than RNA.

DNA Replication

DNA self-replicates; this means that each DNA strand serves as a template for new strands creation. During DNA replication, the double helix exposes the two DNA strands. After unzipping the DNA, it creates 2 new strands – the leading and lagging strands. The leading strand replicates, while the lagging strand divides into smaller pieces. RNA, on the other hand, is not self-replicating. Instead, it is synthesized from DNA via the transcription process. It copies a part of the DNA to produce an RNA molecule during this process.


Tomohiro Takano
Tomohiro Takano
Co-Founder and CEO