Meiosis and Non-disjunction

The following clip looks at the stages of meiosis and does a good job explaining it.

The next clip identifies the differences between male and female gamete formation.

The following clip looks at the process of non-disjunction in meiosis II which can lead to the development of monosomies or trisomies.

The second clip looks at the process of a non-disjunction in meiosis I which can lead to the development of monosomies or trisomies.

Notice the number of chromosomes in each gamete. Notice the difference in what is occuring with the spindle. How does non-disjunction in meiosis I differ from non-disjunction in meiosis II?

Cell Division/Mitosis

Here is a quick overview of mitosis…it does not label the stages, but has a nice little movie at the end showing division actually taking place…

This next video labels the stages and shows a pretty cool (I think) computer simulation of the process.

Don’t forget the stages of the cell cycle:

    G1 Phase – Cell Growth
    S Phase – DNA Replication
    G2 Phase – DNA Checking & Preparation for Division
    M Phase (Mitosis)

      Prophase
      Metaphase
      Anaphase
      Telophase
      Cytokinesis

I’ve updated this post to include an additional video covering the phases of mitosis and what happens.