Question

In multicellular organisms (such as an animal), all the cells have identical DNA (exact same DNA). Explain how different cells in the same organism can have such different structures and functions if they all have the same instruction manual (DNA)?

Answer 1

Although all the cells have same type of DNA but than also different cells have different functions and structurs. This all is possible because of the gene regulation. In our body each cell type has the set of different active genes. The pattern of gene expression make the cell to have different set of proteins. This makes the each cell unique to do the specialized jobs. Example, liver cell remove the toxin from the body but not the neurons, this is because there is different sets of gene expressed in the liver cell. Those gene are not active in the neurons.