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Mitosis and the Cell Cycle – How the Trillions of Cells in a Human Body Developed from a Single Cell

In this minds-on analysis and discussion activity, students learn how the cell cycle produces genetically identical daughter cells. They analyze how DNA replication and mitosis work together to ensure that each new cell gets a complete set of chromosomes with a complete set of genes.

To understand how a single cell (the fertilized egg) can develop into the trillions of cells in a human body, students analyze an exponential growth model for the increase in number of cells. The final section provides a brief introduction to cellular differentiation.

This activity can be used as an introduction to mitosis or to reinforce understanding of mitosis. A hands-on version of this activity is available as “Mitosis and the Cell Cycle – How a Single Cell Develops into the Trillions of Cells in a Human Body”.

The Student Handout is available in the first two attached files and as Google doc designed for use in online instruction and distance learning. The Teacher Notes, available in the last two attached files, provide instructional suggestions and background information and explain how this activity supports the Next Generation Science Standards (NGSS).

Mitosis SH.docx4.59 MB
Mitosis SH.pdf925.19 KB
mitosis TN.docx1.51 MB
mitosis TN.pdf464.05 KB


iwaldron's picture

September 2021 revision

The September 2021 revision improved the wording of some questions and improved some of the figures in the Student Handout and clarified some points in the Teacher Notes.

iwaldron's picture

2021 revision

We have added a brief section on cell differentiation to help students understand that the cell cycle and mitosis are not the only processes needed to make a human body. In addition, we have changed the symbols for the alleles of the genes on the model chromosomes to avoid confusion between lower case and capital letters (e.g., s and S). 

micheal forbes's picture


I dont have the answer key to check the answers

iwaldron's picture

Answer key

Please check the Teacher Notes for information about how to get the answer key as well as background information and instructional suggestions.

Serendip Visitor's picture

Key does not match Student Handout

The key that was emailed to me does not match the SHO above. The key is 5 pp. and the handout is 8 pp.; the key stops at #15 and the content is different after page 3?

iwaldron's picture


I am puzzled by your message, since the student handout at this link is five pages long in the word doc and the PDF. Please check again.

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