If all cells in your body have the same DNA,how can you have different types of cells

Question

If all cells in your body have the same DNA,how can you have different types of cells

Answer 1

As we known,all cells in our body have the same DNA,however,even if they have exactly the same DNA,why are eyes and lungs so different?The answer lies with what DNA is and how it works.
Human's DNA contains all of the information needed for making you.This information is stored in the over 30,000 human genes found in almost all your cells.Therefore,to get at the information,a gene must be turned on (expressed) and the information turned into something useful,a protein.Once made,that protein goes out into the cell and performs some set of specific tasks.For example,hemoglobin,a protein found in red blood cells,carries oxygen to cells and carbon dioxide away.
For a cell to work,1000's of these proteins must be made,each doing its particular job.Eyes and lungs are so different because different sets of proteins are made in the various eye and lung cells.In other words,in the eye,genes are turned on for seeing and the "breathing" genes are off.In lung cells,the situation is reversed.