In this activity, students learn how cell specialization takes place in vertebrate embryos. They begin by exploring a gallery of different kinds of specialized cells. They also explore how white blood cells are specialized to fight viruses. They learn about the role of master control genes in cell development. Finally, they learn about the significance of -- and controversy surrounding -- stem cell research, and then analyze the different points of view in the stem cell debate.
- Compare the structure and function of different specialized cells
- Learn how cell specialization occurs in embryos
- Recognize the role of master control genes in cell development
- Understand the significance of stem cell research
- Analyze different points of view in the debate over stem cell research
- Two to three class periods
- Gallery of Cells JPEG Image
- Immune Cells in Action QuickTime Video
- The Embryo Takes Shape QuickTime Video
- Gene Control QuickTime Video
- Genetic Tool Kit QuickTime Video
- Stem Cells Breakthrough QuickTime Video
- Stem Cells: Seeds of Hope? QuickTime Video
- Stem Cell Debate HTML Document
- How have each of these cells (red blood, epithelial, muscle, liver, bone, neuron, and immune cells) become specialized to perform a specific function?
2. Ask students to consider the following question while they watch the The Embryo Takes Shape video:
- If each cell has identical DNA, how do you think a cell becomes specialized?
3. Show the The Embryo Takes Shape video. Discuss the following:
- What directs the sequence of events that turn a blob of cells into an embryo with specialized tissues and organs?
- The narrator says that "cells talk to each other." What does that mean?
- How do cells in different parts of the embryo become different kinds of cells and organs?
- What kinds of proteins are found in different cells and organs?
- What tells the cells which kinds of proteins to make?
- What is the relationship between DNA, genes, and the proteins that are produced in cells?
4. Show the Gene Control video. Discuss the following:
- What is the role of control genes?
- What kinds of chemicals do you think the mother deposits on the egg?
- How do you think they might "turn on" the control gene?
5. Show the Genetic Tool Kit video. Discuss the following:
- What do homeobox genes code for in animals?
- Why are homeobox (also called homeotic) genes called the master control genes, or master switches?
- What other organisms besides fruit flies have homeobox genes?
- What does the presence of homeobox genes in fruit flies and mice indicate about their evolution?
- What does the presence of homeobox genes suggest about the evolution of different eyes in different organisms?
- Why are stem cells considered so valuable for medical research?
- What are three sources of stem cells and the advantages and disadvantages associated with using each?
- How might a stem cell be used to treat a disease such as diabetes?
- What issues surround the debate over government funding of stem cell research?
- What issue do you think needs to be debated as we make decisions about stem cell research?