Meiosis: Mitosis and Homologous Chromosomes Exchange
Meiosis Modeling Activity
Background Information
Meiosis is the process by which eukaryotic organisms produce egg and sperm having half the genetic information (haploid) of the other cells in the organism’s body (diploid). You will notice some similarities to mitosis but some definite differences in meiosis that result in genetic diversity in the gametes as well as the offspring formed by the eventual fusion of the egg and sperm.
Two of the most noted differences in meiosis are that 1) there are two complete divisions resulting in four daughter cells and, 2) meiosis has crossing over, an even that occurs in Prophase I that increases genetic variation in the gametes. Crossing over occurs between homologous chromosomes. These are the pairs of chromosomes in an organisms body that carry genes for the same trait located at identical positions on the two chromosomes. Even though they carry the same gene they may, however, possess different alleles for the gene which result in different forms of the trait.
Pre-Lab (3 points):
1. Draw a tetrad in the space below and label the following: centromeres, sister chromatids, homologous chromosomes.
2. What are the two elements of meiosis that add variation to our population? (Hint: one occurs in prophase I and the other in metaphase I).
3. Which of the chromosomes #2-5 could be homologous with chromosome #1? Explain your answer. I think number 5 because it is the exact same as 1.
Lab:
1. First view the recording on my message board under “Supplemental Learning Materials” for this lab. You will need the “code words” from the recording for one of your conclusion questions. Link to recording: http://www.connectionslivelesson.com/p2fwrdno8yk/
2. After you have viewed the recording, gather your required materials. You will need 4 forks, 4 knives, 4 spoons, 6 rubber bands, and
Background Information
Meiosis is the process by which eukaryotic organisms produce egg and sperm having half the genetic information (haploid) of the other cells in the organism’s body (diploid). You will notice some similarities to mitosis but some definite differences in meiosis that result in genetic diversity in the gametes as well as the offspring formed by the eventual fusion of the egg and sperm.
Two of the most noted differences in meiosis are that 1) there are two complete divisions resulting in four daughter cells and, 2) meiosis has crossing over, an even that occurs in Prophase I that increases genetic variation in the gametes. Crossing over occurs between homologous chromosomes. These are the pairs of chromosomes in an organisms body that carry genes for the same trait located at identical positions on the two chromosomes. Even though they carry the same gene they may, however, possess different alleles for the gene which result in different forms of the trait.
Pre-Lab (3 points):
1. Draw a tetrad in the space below and label the following: centromeres, sister chromatids, homologous chromosomes.
2. What are the two elements of meiosis that add variation to our population? (Hint: one occurs in prophase I and the other in metaphase I).
3. Which of the chromosomes #2-5 could be homologous with chromosome #1? Explain your answer. I think number 5 because it is the exact same as 1.
Lab:
1. First view the recording on my message board under “Supplemental Learning Materials” for this lab. You will need the “code words” from the recording for one of your conclusion questions. Link to recording: http://www.connectionslivelesson.com/p2fwrdno8yk/
2. After you have viewed the recording, gather your required materials. You will need 4 forks, 4 knives, 4 spoons, 6 rubber bands, and