What is the gene? Give its functions.

As cell is the basic unit of life, similarly genes are the basic unit of living organisms. They provide traits or characteristics to organisms that pass on from generation to generation. These are nucleotide sequences of DNA or RNA which encodes the genetic information. There are different numbers of genes in different species. For example: humans have 25,000 genes in its genome, E.coli (bacteria) has 5,500 genes and Arabidopsis thaliana (plant) has almost 25,500 genes in their genomes. Since genes are made of DNA, they can also be called as unit of heredity. This double helix structure encodes the basic instructions of living organisms. This is the reason why children have characteristics similar to their parents, as this nucleic acid passed down from generation after generation with multiple modifications thus distinguishing you a bit from your parents. It recites inside the nucleus of a cell. This twisted staircase structure is made up of four nitrogenous bases: Adenine (A), guanine (G), cytosine (C) and thymine (T). It is composed of de-oxyrisbose sugar. It was discovered by James Watson and Francis Crick. This genetic material is enclosed in a nuclear envelope of only eukaryotes and the two membranes bound organelles called mitochondria and chloroplast. They are not protected by a nuclear envelope in prokaryotic organisms. But RNA is the genetic material of viruses.

Genes determine the character of organism; they can affect specific traits through any mutation via external or internal environment. These mutations are a result of distinguished traits among individuals. Sometimes these mutations can be negative which can affect the health of organisms. Causing some diseases, such as sickle-cell anemia and Huntington's disease, and since genes are heritable it will cause the disease to be inherited as well.


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