Question

Briefly explain what is the nucleotide and its structure.

Answer 1

DNA:

• The DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all the other organisms.
• Nearly each and every cell in a person's body has the same DNA.
• The ability of DNA to carry the genetic information required by a cell to reproduce itself is closely related to the structure of DNA molecules.

Nucleotides:

• DNA is a polymer and consists of a long chain of monomers called nucleotides.
• The DNA molecule is said to be a polynucleotide.
• Each nucleotide has three parts: a sugar, a nitrogen containing ring-structure called a base, and a phosphate group.
• The sugar present in DNA is a five carbon pentose called 2'-deoxyribose in which the OH group on carbon 2 of ribose is replaced by hydrogen.
• The carbon atoms in the sugar are numbered 1-5. The numbers are given a dash (') referred to as prime to distinguish them from the numbers of the atoms in the base.
• The numbering is important because it indicates where other components of the nucleotide are attached to the sugar.
• Nucleotides contain one of four bases: adenine, guanine, thymine or cytosine.
• These are complex molecules containing carbon and nitrogen ring structures.
• Adenine and guanine contain two carbon-nitrogen rings and are known as purines.
• Cytosine and thymine contain a single ring and are called pyrimidines.
• The bases are attached to the sugar by a bond between the 1' carbon of the sugar and a nitrogen at position 9 of the purines or position 1 of the pyrimidines.
• A sugar plus a base is called a nucleoside.
• Nucleotides contain phosphate groups (PO4) attached to the 5' carbon of the sugar.
• A nucleoside is called a nucleotide when a phosphate group is attached, the attachment can consist of one, two or three phosphate groups joined together.
• The phosphate groups are called α, β, andγ, with a directly attached to the sugar.
• Nucleotides may exist in cells as individual molecules (nucleotide triphosphates play an important role in cells as the carriers of energy used to power enzymatic reactions) or polymerized as nucleic acids (DNA or RNA).
  

Nucleotide:

• DNA is a polymer containing chains of nucleotide monomers.
• Each nucleotide contains a sugar, a base and a phosphate group.