Question

Explain how all cells in a person's body have the same genome, but are of hundreds of different types that look and function differently.

Short answer

All cells in a person's body have the same genome, but they express different parts of it. In the process of differentiation, cells become specialized by turning on or off sets of genes, leading to production of specific proteins that determine a cell's function. Thus, creating hundreds of different cell types.

Step-by-step solution

Essential Understanding of the Cell and Genome

Each cell in an individual's body, except for the sperm and egg cells, contains the same genome - the complete set of genetic information. DNA, which is stored in the nucleus of our cells, carries the instructions for build and maintaining the body.

Gene Expression

Even though every cell has the same genome, they do not all use this information in the same way. Genes within DNA can be turned on (expressed) or turned off (repressed). This regulation of gene expression determines what proteins a cell manufactures, which in turn determines the type of cell it will become and its function.

Cell Differentiation

In the early stages of development in the womb, a process called 'differentiation' begins. Cells begin to take on specific functions, becoming specialized. They become different types of cells (like skin cells, muscle cells, nerve cells, etc.) based on the specific combination of genes that are turned on or off in that cell.