Nucleic Acid and Structure

Nucleic Acid & Structure

Nucleic Acid : 

•Definition: Nucleic acids are large biomolecules that are crucial in all cells and viruses. 

•Nucleic Acid is made up of three components-  

 i. A Nitrogenous base

ii. A Pentose(five carbon) sugar

iii. A Phosphate group

•The two main types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid(RNA). 

•DNA and RNA are made up of monomers known as nucleotides.

DNA:

•Definition: DNA is a molecule that carries the genetic instructions for the development, functioning, and reproduction of all living organisms. It consists of a double helix structure made up of nucleotides containing the bases adenine, thymine, cytosine, and guanine.

•Structure DNA is an antiparallel double helix  composed of nucleotides. Each nucleotide consists of a phosphate group, a sugar (deoxyribose), and one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G). A always pairs with T, and C always pairs with G, forming complementary base pairs.

•Function: DNA contains the genetic instructions necessary for the development, functioning, growth, and reproduction of all known organisms. It serves as the blueprint for the synthesis of proteins, which are essential for the structure and function of cells.

•Why is Thymine Present in DNA?

✔ Thymine has a high resistance to photochemical mutation.

✔ It makes genetic code more durable.

✔ It has great resistance.

•Chargaf 's rules:

One other key piece of information related to the structure of DNA came from Austrian

biochemist Erwin Chargaff. Chargaff analyzed the DNA of different species, determining its

composition of A, T, C, and G bases. He made several key observations:

    >A, T, C, and G were not found in equal quantities (as some models at the time would have predicted). 

    >The amounts of the bases varied among species, but not between individuals of the same species. 

    >The amount of A always equalled the amount of T with double bond, and the amount of C always equalled the amount of G with triple bond (A = T and G = C)

Gene:

•Definition: Genes are fundamental units of heredity and carry the genetic information necessary for the development, functioning, and reproduction of living organisms.

•Structure: Genes consist of coding regions (exons) that specify the amino acid sequence of a protein, as well as non-coding regions (introns, regulatory sequences) that control gene expression and other cellular processes.

•Function: Genes encode proteins that play critical roles in various biological processes, including metabolism, growth, development, and immune response. Some genes also produce non-coding RNA molecules with regulatory functions.

•Inheritance: Genes are passed from parent to offspring through the transmission of chromosomes during sexual reproduction. They contribute to the phenotypic traits and characteristics observed in individuals.

Genome:

•Definition:The genome encompasses all the genetic material present in an organism, including both coding and non-coding regions. 

•The entire genetic content of a cell is known as its Genome. 

•The study of genomes is genomics.

•Composition: It consists of DNA sequences organized into chromosomes, which are further divided into genes and intergenic regions.

•Function: The genome carries the instructions for the development, growth, and functioning of an organism. Genes within the genome encode proteins, regulate gene expression, and control various cellular processes.