Cell Differentiation

Understandings: Specialized tissues can develop by cell differentiation in multicellular organisms & differentiation involves the expression of some genes and not others in a cell’s genome.

Every cell in a multicellular organisms contains all the genes of that organism. However, the genes that are activated vary from cell to cell. The reason we have different types of cells in our body (the cells in your eyes are not the same as the ones that make up your hair) is because different genes are activated in different cells. Genes encode for proteins and the proteins affect the cell’s structure and function. By activating certain genes and not others, cells can differentiate and form specialized tissues. For example, the gene that produces keratin will be active in hair and nail cells because keratin is the protein which makes up hair and nails. Differentiation depends on gene expression which is regulated mostly during transcription. It is an advantage for multicellular organisms as cells can differentiate to be more efficient unlike unicellular organisms who have to carry out all of the functions within one cell.

Summary:

- Ever cell in a multicellular organism contains all genes of that organism 
- Not all genes are activated in every cell
- The genes that are activated encode for proteins
- Proteins affect the structure and function of cells
- By activating certain genes and not others, the cells are able to differentiate and form specialized tissues
- Gene expression is regulated mostly during transcription