Secrets of the X chromosome – Robin Ball, TED-Ed

The sequence of DNA that we inherit from our parents encodes directions for making our cells and giving us specific traits. Identical twins have the same DNA sequence, so how can one twin end up with a genetic disorder while the other twin does not? Robin Ball explains how the secret lies in X chromosome inactivation.

Lesson by Robin Ball, animation by Anton Trofimov.

Student Activity: Sock Mitosis


This demonstration is a great way for students to model the stages of mitosis. Images of the different stages in textbooks are static snapshots and many students have difficulty grasping the idea that mitosis happens as part of a continuous cycle.

What happens?

Students will observe a model going through each stage of mitosis.

Click here to download the complete activity….