Modeling Meiosis
Materials (per pair)
· 4 2-inch pipe cleaners, 2 of one color, 2 of another color
· 4 4-inch red pipe cleaners, 2 of one color, 2 of another color
· 1 piece of yarn
Procedure
Refer to the following diagram of the stages of Meiosis to model the stages of meiosis:
Interphase
1. Form a circle with the piece of yarn to model the cell membrane (do not tie the ends together).
2. Place one large and one small pipe cleaner of each color inside the cell. These represent chromosomes during the G1 phase of Interphase (note: DNA would probably be in chromatin form at the stage, not chromosomes, but we’ll have to model them as chromosomes)
3. During the S Phase of Interphase, all of the chromosomes are copied.
Add the matches of each chromosome to your cell.
Meiosis I
4. Match the exact copies of each pipe cleaner. Twist the matching pieces together to form individual chromosomes.
Draw the chromosomes in the top bubble of the diagram below.
5. Prophase 1: Find one pair of chromosomes that are the same size and place them together inside the cell. Find the other two chromosomes that are the same size and place them together inside the cell. One of each kind of chromosome was passed to this child from the mother and the other one came from the father.
6. Metaphase 1: Next, the pairs of chromosomes line up in the middle of the cell. Move each pair of chromosomes to the middle of your cell.
Think about Independent Assortment. How many different ways could you line up the chromosomes in order to make genetically different daughter cells?____________________________________________
7. Anaphase 1: Now, the chromosome pairs separate so that one of each pair of chromosome moves to opposite sides of the cell. Model this process in your cell.
8. Telophase 1 and Cytokinesis: The cell pinches in the middle and then splits. Move and then cut the yarn to show this cell being divided in half.
Draw the chromosomes in second-level bubbles in the diagram below.
How many cells have been formed? __________________________________________
How many chromosomes are in each new cell? _________________________________
Meiosis II
9. Prophase 2: Not much happens in Prophase 2 (the nucleus dissolves and spindle fibers form – you don’t have to model this)
10. Metaphase 2: The chromosomes line up in the middle of each new cell. Move your chromosomes to show this.
11. Anaphase 2: The 2 halves (sister chromatids) of each chromosome separate and move away from each other to opposite sides of the cells. Untwist the pipe cleaners and move one of each pipe cleaner to opposite sides of your two new cells.
12. Telophase 2 and Cytokinesis: Each of the two cells pinches in the middle and then divides in half. Move and then cut the yarn to show these cells being divided in half.
Draw the chromosomes the 3rd-level bubbles of the diagram below.
How many cells are formed? ______________________________________________
How many chromosomes are in each new cell? _______________________________
Do all of the cells have the same combination of chromosomes as each other? _____
Do all of the new cells have the same combination of chromosomes as the first cell you modeled at the beginning of the lab? ________________________________________
What can you conclude about the process of meiosis?