Monomers of DNA and RNA | Their Chemistry & Shape

Monomers are molecules which can bind to similar molecules to form long chains or polymers.

Organic compounds like carbohydrates, amino acids, nucleic acids, etc. can be obtained as monomers.

Both DNA and RNA are nucleic acids in all most all the cells.

These both molecules are large strands and are made of nuclear bases and carbohydrate monomers.

As the name indicates DNA (deoxyribonucleic acids, RNA (ribonucleic acids) both of them have a similar structure and are made of similar monomers.

These two nucleic acids DNA and RNA are found in all the living cells, virus capsid and even in space. Further, they can be made in the laboratory.

Monomers of DNA and RNA

Monomers of DNA and RNA

Monomers of DNA

DNA is present as a double stranded structure with two strands aligned in  a helix.

DNA has five monomers of which one is a carbohydrate monomer while the remaining four are nuclear bases.

The carbohydrate monomer is a five carbon sugar namely deoxyribose.

Monomers of DNA deoxyribose

The four nuclear bases include two purine bases namely

a) Adenine

b) Guanine

Monomers of DNA and RNA

By: Wikicommons

and two pyrimidine bases namely

c) Thymine

d) Cytosine

Monomers of DNA and RNA

Monomers of RNA

Like DNA, RNA also has a single carbohydrate monomer namely the ribose sugar which is a five carbon sugar.

Monomers of RNA ribose sugar

Then there are four nuclear bases of which two are purine bases like

a) Adenine

b) Guanine

and two pyrimidine bases as

C) Uracil

d) Cytosine.

So the purine bases are the same monomers in both the DNA and RNA but the pyrimidine bases are different in between these two nucleic acids. There is uracil instead of thymine in the RNA strand.

In both these molecules, the sugar monomers are held together to form a long strand by a phosphodiester bond. While the nuclear bases are bound to the carbohydrate monomer.

The DNA molecules is a double strand structure while the RNA is a single strand structure.

The double strand structure of DNA is possible due to the hydrogen bonds in between the nuclear bases of both chains.

DNA is the genetic material and is more stable than the RNA. DNA resides in the nucleus as double strand structure and a single strand structure in mitochondria. RNA is less durable genetic material and is present mostly in the cytoplasm of the cell.

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