The Nucleus
Except hair, sperm and red blood cells, each cell has a nucleus. There are 100 trillion cells in the human body
The Chromosomes
Every nucleus in each cell has 46 chromosomes arranged in 23 pairs. Each parent contributes a chromosome to each of these pairs when a child is conceived.
The DNA
The chromosomes are filled with tightly coiled strands of DNA.
The Double Helix
The arrangement of genes on the DNA double helix determines everything, from the colour of your eyes to your chances of getting a disease. Faulty genes passed on from a parent, or an ancestor, to a child can cause inborn disorders.
The Genes
DNA uses a biochemical alphabet of A, T, C, G, chemical bases that join in pair (A only with T; G only with C). Genes are sequences of these letters. There are one lakh genes that make up DNA
