Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the second of three Science Objects in the Cell Division and Differentiation SciPack. It explores the processes that take place within cells that allow for selective gene expression, which leads to the specialization and variation of cells in organisms.
Cell functions are turned on and off by regulatory genes, through changes in the activity of the functions performed by proteins. Although cells in a multi–celled organism begin alike, having essentially identical genetic instructions, selective expression of individual genes (cells are regulated) causes the unspecialized embryonic stem cells to become very different (cells can differentiate). The embryonic stem cells become increasingly more specialized, differentiating into a variety of cell types. Selective expression results when different parts of the genetic instructions are used in different types of cells, influenced by the cell's environment and past history.
The work of the cell is carried out by the many different types of molecules it assembles, mostly proteins. In specialized cells, other protein molecules may carry oxygen, effect contraction, respond to outside stimuli, or provide material for other body structures. In still other cells, assembled molecules may be exported to serve as hormones, antibodies, or digestive enzymes.
- Explain the role of regulatory genes and how they function.
- Explain how it is possible for different types of cells, such as bone cells and liver cells, to have identical genetic instructions and function differently.
- Describe the role of embryonic stem cells in the development and growth of complex organisms.
- Interpret data presented in graphs and charts from experiments addressing the role that protein-related variables (such as hormones, antibodies and digestive enzymes) play in the regulation of a complex organism’s life processes.