Home General Studies General Science

What are "DNA", "RNA" and "Ribosomes" ?

news-details Image Source Nov 10, 2020 10:03 IST , Updated: Mar 16, 2021 10:03 IST · 3 min read

What is Deoxyribonucleic acid (DNA)

Deoxyribonucleic acid, commonly known as DNA, is the hereditary complex molecule present in humans and almost all other organisms.

DNA consists of two strands, arranged in a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.

These strands are made up of subunits called nucleotides, each nucleotide contains a phosphate, a 5-carbon sugar molecule and a nitrogenous base.

Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).

Mitochondria are structures within cells that convert the energy from food into a form that cells can use.

The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T).

An important property of DNA is that it can replicate, or make copies of itself.

DNA's molecular structure was first identified by James Watson and Francis Crick in 1953. They won the nobel prize for the same in 1962.

DNA Profiling is the process of determining an individual characteristics and most commonly used as a forensic technology to identify a person.

What is Ribonucleic acid (RNA)

RNA only has one strand, but like DNA, is made up of nucleotides, RNA strands are shorter than DNA strands.

RNA is principally involved in the synthesis of proteins, carrying the messenger instructions from DNA, which itself contains the genetic instructions required for the development and maintenance of life. In some viruses, RNA, rather than DNA, carries genetic information.

RNA converts the genetic information contained within DNA to a format used to build proteins, and then moves it to ribosomal protein factories. There are three types of RNA:

1) Messenger RNA (mRNA)

Messenger RNA (mRNA) copies portions of genetic code, a process called transcription, and transports these copies to ribosomes, which are the cellular factories that facilitate the production of proteins from this code.

2) Transfer RNA (tRNA)

Transfer RNA (tRNA) is responsible for bringing amino acids, basic protein building blocks, to these protein factories, in response to the coded instructions introduced by the mRNA. This protein-building process is called translation.

3) Ribosomal RNA (rRNA)

Ribosomal RNA (rRNA) is a component of the ribosome factory itself without which protein production would not occur.


They are both linear polymers, consisting of sugars, phosphates and bases, but there are some key differences which separate the two.

There are two differences that distinguish DNA from RNA: (a) RNA contains the sugar ribose, while DNA contains the slightly different sugar deoxyribose (a type of ribose that lacks one oxygen atom), and (b) RNA has the nucleobase uracil while DNA contains thymine.

While the structure of DNA is a double-helix in eukaryotic cells, RNA is typically single-stranded and comes in various forms. The single-stranded structure of RNA allows this molecule to fold back on itself and form various stable secondary structures as necessary.

DNA is a much longer polymer than RNA. A chromosome, for example, is a single, long DNA molecule, which would be several centimetres in length when unravelled.

Due to its deoxyribose sugar, which contains one less oxygen-containing hydroxyl group, DNA is a more stable molecule than RNA.


Ribosome, particle that is present in large numbers in all living cells and serves as the site of protein synthesis. Ribosomes are the sites at which information carried in the genetic code is converted into protein molecules.

The newly formed proteins detach themselves from the ribosome site and migrate to other parts of the cell for use.

Ribosomes occur both as free particles in prokaryotic and eukaryotic cells and as particles attached to the membranes of the endoplasmic reticulum in eukaryotic cells.

Ribosomes are made up of ribosomal proteins and ribosomal RNA (rRNA). In prokaryotes, ribosomes are roughly 40 percent protein and 60 percent rRNA.

Popular in General Science