Lab

Lab 5 – Meiosis

Before you begin your work, please read very carefully the Introduction in the Lab Manual and study Figure 2 closely. Then answer the two pre-lab questions as thoughtfully and in depth as you can.

Experiment 1: Following Chromosomal DNA Movement through Meiosis

(a) Part 1: You will simulate meiosis with two pairs of homologous chromosomes by using snap beads (they are in your kit). Then follow the instructions by simulating meiosis I and meiosis II. You may either photograph each stage and paste it into Part I – Meiotic Division Beads Diagram, or, you may draw each stage directly onto the lab page. Be sure to use two different colors.

(b) Part 2: This time, you will begin again with two sets of homologous chromosomes, but then make crossing-over happen for each set. Following that, you will then go through meiosis I and II again and draw, or photograph, each step carefully. You need to write down the number of chromosomes for each cell and stage in Part 1 and Part 2. – Explain the differences in outcome between Part 1 and Part 2.

You will find several questions at the end of experiment 1; please answer them all. You should remember that each and every species has different numbers of chromosomes. For example, humans have 23 pairs, that is, 46 total number of chromosomes. Mice have 40 chromosomes, dogs have 78, giraffes have 30, and some plants have over 200 chromosomes. The number of chromosomes found in the cells of individualspecies, are the result of their individual evolutionary history.

Experiment 2: The Importance of Cell Cycle Control

This will allow you to do some real-life research based on karyotypes. When you formulate your hypothesis please remember that it should be a brief, reasonable statement of expected outcomes. Please copy and paste five actual and complete karyotypes. Then answer the questions carefully.