Thursday, March 24th

Today we tried something new. I wanted to do something more interactive so we attempted what I will call a human video of meiosis. Here is what is required:

Casting Call (8 students, can rotate throughout class):
-Homologous chromosome (2 students)
-Sister chromatids (additional 2 students)
-Centrosomes (4 Students)

Materials
-4 jump ropes
-4 large hula hoops
-2 pairs long blue socks (soccer socks work well)
-2 pairs long orange socks (sock color doesn't matter, just need two different colors)
-1 pair blue ankle socks
-1 pair orange ankle socks

Procedure

Interphase
-Normal state of cell activity (non-dividing)
-homologous pair put a long sock on one arm and one leg (same side of body)
-boy (representing chromosome from dad) wears one color
-girl (representing chromosome from mom) wears the other color
-put socks on the arm and leg that is next to their homologous pair
-homologous chromosomes stand side by side inside the hula hoop
-show that at this point they are chromatin (ex. make arms wavy and loose)
-2 students with the "COPY" sign join their original chromosome in the hula hoop and link arms
*NOTE: Emphasize that when the copies are made they are attached to the original
chromosome from the beginning
-Copies wear the same color socks on their arm and leg as their orignial chromosome, but
put on outside arm and leg
-Copies and Originals link arms (non-socked arms) to be bound by the centromere
-"Socked" arms and legs between the sister chromatids should make an "X" when held out
-Now you have two sister chromatids in the hula hoop (nuclear membrane)

Prophase
-Nuclear Membrane (hula hoop) disappears
-Chromatin condenses into chromosomes (sister chromatids make an "X" with socked arms/legs
-2 centrosomes come out and stand by each other holding jump ropes bundled up
-Centrosomes slowly start to move away towards opposite ends of the cell, releasing jump rope (spindle fiber) as they move along, expanding cellular membrane
-Demonstrate ability to cross over by putting ankle sock of the opposite color over the ends of the soccer socks

Metaphase
-Tetrads line up on imaginary metaphase plate in the middle of the cell
-Centrosome students hold one end of the jump rope and sister chromatids hold in the linked arms
-Linked arms represents the centromere so the hand can represent the kinetochore
-Emphasize Spindle fibers attach to the kinetochore which is on the centromere

Anaphase
-Once spindle fibers are attached centromeres reel sister chromatids towards them to be on opposite ends of the cell
-Emphasize Meiosis I is all about separating the homologous chromosomes, or separating the tetrad

Telophase
-nuclear membranes reform around sister chromatids (2 hula hoops)
-spindle fibers disappear
-cellular membrane separates
-Prouduct: 2 haploid cells with copies (sister chromatids), MUST GO TO MEIOSIS II TO SPLIT COPIES FROM ORIGINALS

MEIOSIS II
-Repeat process of Meiosis I except this time instead of separating the tetrad you are separating the sister chromatids from each other
-Outcome: 4 haploid cells-4 hula hoops with one person each