• Learn how cells grow, divide, and differentiate.
• Explore the cause of cell mortality and how some cells can overcome it.
• Discover how cells, especially stem cells, can be used in research and health care.

Are cells immortal? What are the implications of cell immortality in research and health care? In this lesson, students will discover the mechanisms that make a cell mortal and how stem cells and cancer cells have the potential to be immortal.

Teacher Preparation:

Print out the Immortal Cells Lab Notebook for every student. Print out the Cell Differentiation Activity for every student. The second page of the activity will need to be cut out, so single-sided printing is recommended.

Distribute a pair of scissors to every pair of students. Print out the Stem Cells in Health Care printable for every student.

Lesson

Start with the Immortal Cells Slideshow.

Show the video The Immortal Cells of Henrietta Lacks. Ask students to write down any questions they have in the Immortal Cells Lab Notebook

Ask students to respond to the following questions in their lab notebook:

• What does immortal mean?
• What causes cells to die?
• If animals can’t be immortal, can cells be immortal?

Slides 4-8
Go through the next few slides to discuss how one cell can become many different types of cells. Tell students that a single cell goes through division to make a cell bundle. Ask students to fill in the diagram of the cell cycle. Discuss the process of mitosis and how cells make exact copies of themselves.

Slides 9-17
Talk about the process of differentiation and how cells lose potency as they differentiate. Tell students that embryonic stem cells are pluripotent, which means they can become any type of cell.

Once a cell has begun to differentiate, it becomes multipotent. A multipotent cell is not as potent as a pluripotent cell. Ask students how they think cells can become different even though they have the same DNA.

Describe how genes can be turned off and on through epigenetics. Epigenetic signals cause some genes to be expressed and some are suppressed. This is what causes cells to have the same DNA but express different genes. For more on epigenetics, check out this lesson.

Pass out the Cell Differentiation Activity. Ask students to cut out the 10 cells from the top of the handout. Follow the directions on the cell differentiation activity.

Note: This activity follows 10 cells as they differentiate into different tissue layers during embryogenesis. The letters on each cell represent different epigenetic signals that are sent to the cells, which cause different genes to be expressed.

Slides 19-28
Discuss the limits of mitosis and the process of telomere shortening with students. Telomeres contain extra DNA that doesn’t code for anything. Because chromosomes shorten with every replication, telomeres protect the vital, coding part of DNA. When the telomeres are gone, the cell dies. Cells can’t be immortal if they lose their telomeres because mutations can occur on the chromosomes during replication. Explain to students that cancer cells can repair telomeres and are therefore immortal. This makes it hard to destroy cancer cells. Cells can also be reprogrammed to become immortal either in cell culture or in the production of induced pluripotent stem cells (iPSC).

Show the video Creating a Heart in a Dish. This video shows iPSC that have been differentiated into cardiomyocytes (heart tissue cells). These cells are derived from patients to learn about their specific heart conditions. The cells begin to pulsate as they grow. After minerals are added to the plate, they begin to pulse in unison. Each segment of the video is 20 seconds long. Ask students to count the number of beats for each segment and record their data in the student journal.

Slides 30-34
Go through the next few slides to discuss the uses of stem cells in research and health care. Have students complete the Stem Cells in Health Care Printable as an optional extension activity.

Ask students to defend the following claim: Cells have the potential to be immortal.

Make sure they use evidence from the lesson to defend the claim.

Discussion

The research into telomere shortening, stem cell production, and cancer cell capabilities is ongoing. New information will likely arise. Encourage students to seek out more current research to update their understanding of this topic.

The Sanford Connection

Sanford Health uses stem cells for many purposes. There are ongoing clinical trials in the field of orthobiologics, which uses stromal vascular fraction to treat rotator cuff tears. This includes stem cells and other cells that help initiate healing. Sanford Research also uses stem cells in research. iPSC are used to study the growth and development of specialized cells. Additionally, immortal cell lines, such as HeLa cells, play an important role in cancer research.

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