DNA (Deoxyribonucleic Acid): Structure & Functions

DNA, or Deoxyribonucleic Acid, is a long, double-stranded molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses.
DNA (Deoxyribonucleic Acid) is composed of two strands forming a double helix, made up of repeating units called nucleotides.
Each nucleotide consists of a sugar (deoxyribose), a phosphate group, and one of four nitrogenous bases—adenine (A), thymine (T), cytosine (C), or guanine (G).

Structure DNA (Deoxyribonucleic Acid):

Double Helix:
- DNA is composed of two long strands that form a double helix, which looks like a twisted ladder.
- Backbone: Each strand consists of a sugar-phosphate backbone, with the sugar being deoxyribose.
- Bases: Attached to each sugar is one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
- Base Pairing: The strands are held together by hydrogen bonds between the bases, with A pairing with T and C pairing with G.
Antiparallel Orientation:
- The two strands run in opposite directions, one from 5′ to 3′ and the other from 3′ to 5′.
Major and Minor Grooves:
- The twisting of the helix creates grooves, which are the sites of protein binding for replication and transcription.
Chromatin and Chromosomes:
- DNA is packaged into chromatin, which further condenses to form chromosomes during cell division.

Genetic Information Storage: DNA holds the genetic blueprint for the development, functioning, and reproduction of all living organisms and many viruses.
Replication: DNA can replicate itself, ensuring that genetic information is passed from cell to cell and from generation to generation.
Gene Expression: DNA sequences (genes) are transcribed into RNA, which then directs the synthesis of proteins.
Regulation: DNA contains regulatory sequences that control the expression of genes, influencing when, where, and how much gene product is made.