Module 5 Cell Division

3.5.1 page 3

Watch and Listen

In the previous unit you considered the creation of sperm and eggs and how they united to start a new human life. You also talked about how the zygote underwent continuous cell division and differentiation to eventually become a new person. In this lesson we have identified those processes as mitosis for growth and differentiation, and meiosis for sperm and egg production. Consider the following video comparing mitosis and meiosis cell division. Without worrying about the specific steps in either process, which will come in a later lesson, use this video to gain an understanding of how these processes differ.

Consider these questions:

• How does the cell prepare for either division?
• What structures are involved during the processes?
• How many daughter cells usually result from meiosis or mitosis?
• How do the daughter cells of mitosis compare with those from meiosis?
• In what ways is mitosis similar to meiosis? How is it different?

Module 5: Lesson 1 Assignment—Lab

Complete the following:  Use the exploration guide to learn how to use the Gizmo to complete the assignment.

Exploration Guide

Human Karyotype Gizmo

 (Log in to the top login box with your Moodle username and password.)

Discuss

Cell division as introduced in this lesson can be dramatic and amazing. From a tiny sperm and egg comes a complete new person. However, we have come to accept less dramatic growth or repair once we have reached maturity. Sure you are still thankful that your bone mended after that break, or your skin closed after that cut, but if you lost a finger or an ear, you would accept there was nothing that could be done.

That may not be the case now. Science is constantly looking for ways to extend natural re-growth or repair. Re-growth of finger tips has been reported with the addition of ground-up pig bladder (a source of stem cells). Perhaps more shocking is our experimentation with growing human tissue or organs inside of animals for transplant. Use the search Internet search terms “mouse human ear BBC” h and follow the link to the BBC website on “Artificial Liver ‘could be grown’ or “Girl may be the first to grow artificial ear.” In both of these reports there is a disturbing picture of a human ear growing on the back of a mouse for transplant.

As promising as these developments are, they bring up many ethical questions. Should scientists be experimenting with tissue or organ re-growth using animals? Discuss this question with your classmates and your teacher in the discussion area.