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Stem Cells

A collection of activities to help students learn about stem cells and consider their potential in research and health.

Go Go Stem Cells Worksheet

This worksheet accompanies the Go Go Stem Cells activity on Learn.Genetics.

Learning Objectives
  • Stem cells give rise to multiple types of cells in response to signals they receive.
  • Stem cells exist all around the body in protective microenvironments called niches.

Go Go Stem Cells Worksheet (fillable pdf)

Stem Cell Tourism Bioethics

Students consider the availability of stem cell therapies in countries with less stringent regulatory policies and procedures. From the perspective of various stakeholder groups they discuss wether scientists should collect and use data from patients who receive experimental treatments that don't meet the domestic ethical and scientific guidelines to which they are subject.

Learning Objectives
  • Regulatory policies for experimental stem cell therapies differ between countries. Patients can travel to obtain an experimental treatment that isn't approved at home.
  • Patients who seek experimental stem cell therapies abroad bring back with them potentially useful information. Should scientists collect and use data from therapies that don't meet the ethical and scientific guidelines of their own country?

Article and Discussion Organizer (fillable pdf)

Ethical debates can bring about some very emotional responses. Discussing a bioethical dilemma from the perspective of a stakeholder "de-personalizes" the process to an extent, making it less likely that a student will feel personally attacked by dissenting opinions. Also, having a role to play prompts students without a personal opinion to consider the issue and join the discussion.

  1. Have students read the short Stem Cell Therapies Background Article.
  2. Choose one of the following bioethical questions to work with:
    • Should scientists use results from experimental overseas stem cell therapies to advance their own work when the therapies don't meet their own country's scientific or ethical guidelines?
    • Some biotech companies are forming partnerships with overseas stem cell clinics and using them to conduct studies that would be illegal for these companies to conduct in their own countries. Should companies be allowed to use the results of these studies to gain approval in their own countries?
  3. As a class, brainstorm stakeholders in this issue. (Sample groups include: Patients awaiting stem cell therapy, Researchers, Patients who have had an unsuccessful stem cell therapy, Private clinics, Medical professionals, Biotech companies, etc.)
  4. Divide the class into 5 or 6 stakeholder groups from the list you generate. Instruct the stakeholder groups to first "get in to character" by filling out items 1–3 on the Discussion Organizer. (Either do this as a group, or as individuals first, then compile responses into group consensus.)
    • Why use a Discussion Organizer? Organizers give students a place to begin when considering a bioethical dilemma and keep the conversation focused.
  5. Next, have the students complete the discussion organizer from the perspective of their stakeholder group.
  6. Option 1: Have each group report out on their discussion and thoughts.

    Option 2 (this option takes more time): Jigsaw-have students recombine in to mixed-stakeholder groups (one representative from each stakeholder group). Have each stakeholder present their perspective to the group (you may want to place a time limit on this). Once all stakeholders have presented, the group must then discuss and make a recommendation.
  • Close the activity by taking a class vote.
  • Have students stand along a continuum from "absolutely yes" to "absolutely no" share their reasoning.
  • Have students write a short essay about their personal beliefs about the issue.
  • Look up the regulatory agencies and policies for these and other countries: United States (Food and Drug Administration), Japan (Pharmaceutical and Medical Safety Bureau) United Kingdom (Medicines and Healthcare Products Regulatory Authority).

Stem Cells in Planaria

Planaria are a common flatworm with an amazing ability to regenerate. If you cut a planarian into multiple pieces, each piece will regenerate an entire worm within 1–2 weeks! A spectacular example of stem cells at work, planaria are an ideal model organism for investigating stem cell biology. They are easy to work with, easy to care for and widely available, making them ideal organisms for classroom use as well. Here are some helpful tips and resources for working with them in your classroom.


Planaria thrive in clean, freshwater streams and lakes. They are photo-negative, so look in dark places such as under rocks and logs.


Tie a piece of liver (or other protein source) to a string, then immerse it in a dark area of a clean freshwater stream or lake. In half an hour or so enough planaria should be feeding on liver for you to collect in a jar.


Most biologic supply companies such as Carolina, or Ward's Natural Science, sell planaria at low cost.

  1. Keep them in an open container of dechlorinated or spring water at room temperature. 1–2 mL of water per worm is adequate, use more for larger worms. Change the water, wiping any mucus off of the inside of the container once per week, especially after feeding.
  2. Planaria are photo-negative, they prefer a dark place such as inside a cabinet or drawer.
  3. Feed planaria small, thin slices of liver or other protein-rich food sources such as raw fish, peanut butter, or hot dogs at least once per week. Remove any excess food after 2–3 hours. Change the water after feeding.
    • You can dye the liver you feed them with food coloring. As the planaria feed on the liver, the coloring will stain their gut, providing an enhanced view of their anatomy.
  4. If the planaria are looking sluggish and unhealthy, resist the urge to clean their container and change the water, this may stress them more. Instead, leave them in a dark place at room temperature without food for a few weeks and they will likely recover.
  • Planaria move slowly when cold. Placing them in a small amount of chilled spring water and/or a chilled petri dish just prior to cutting makes it easier to keep up with them to make your cuts.
  • Use plastic transfer pipets or eyedroppers to transfer planaria from one dish to another.
  • Use microscope slide cover slips or sharp razors to make your cuts.
  • Planaria will regenerate after being cut in a number of ways.
  • Most species of planaria will regenerate completely within 1–2 weeks. Do not feed your planaria while they are regenerating.

Which type of stem cell would you use?

Presented with a scenario outlining a potential stem cell therapy, students consider using each type of stem cell for the therapy, then make a recommendation as to which type is best for this particular application.

Learning Objectives
  • There are multiple types of stem cells, some are better suited than others for specific applications.

Student Pages (fillable pdf)

Teacher Guide (pdf)


Funding for this project was provided by a Science Education Partnership Award from the National Center for Research Resources, a component of the National Institutes of Health.