Tackle this experiment with drawings.

Procedure

Meiosis I

A. As prophase I begins, chromosomes coil and condense in preparation for replication.

1. Using one single color of bead, build a homologous pair of duplicated chromosomes. Each chromosome will have 10 beads with a di%uFB00erent colored centromere in it.

For example, if there are 20 red beads, 10 beads would be snapped together to make two di%uFB00erent strands. In the miIDle of each of the 10 bead strands, snap a di%uFB00erent colored bead in to act as the centromere.

Now, repeat these steps using the other color of bead.

2. Assemble another homologous pair of chromosomes using only 12 (that%u2019s 6 per strand) of the %uFB01rst color bead. Place another, di%uFB00erent colored bead in the miIDle of each to act is its centromere. Repeat this step (2 strands of 6 beads plus a centromere) with the other color of beads.

B. Bring the centromeres of two units of the same color and length together so they can be held together to appear as a duplicated chromosome.

1. Simulate crossing over. Bring the two homologues pairs together (that%u2019d be the two pairs that both have 10 bead strands) and exchange an equal number of beads between the two.

C. Con%uFB01gure the chromosomes as they would appear in each of the stages of meiosis I.

Meiosis II

A. Con%uFB01gure the chromosomes as they would appear in each stage of meiosis II.

B. Return your beads to their original starting posion and simulate crossing over. Track how this changes the ultimate outcome as you then go through the stages of meiosis I and II.

C. Using the space below, and using blue and red markers, draw a diagram of your beads in each stage. Beside your picture, write the number of chromosomes present in each cell.

Meiosis I

Prophase I

Metaphase I

Anaphase I

Telophase I

Meiosis II

Prophase II

Metaphase II

Anaphase II

Telophase II

What is the state of the DNA at the end of meiosis I? What about at the end of meiosis II?