Lesson Plans

Biology 5th Edition ©1999

by Campbell, Reece, Mitchell

Week 8: Meiosis and Mendelian Genetics

Chapter 13: Meiosis and Sexual Life Cycles
Chapter 14: Mendel and the Gene Idea

College Board Performance Objectives:

• Describe features of meiosis that are important in sexual reproduction.
• Explain why meiosis is important in heredity.
• Explain how meiosis is related to gametogenesis.
• Explain the key mechanical and genetic differences between meiosis and mitosis.
• Explain how Mendel's work laid the foundation of modern genetics.
• Explain the principal patterns of inheritance.

College Board Lab Objectives:

• Recognize the stages of mitosis in a plant or animal cell.
• Calculate the relative duration of the cell cycle stages.
• Describe how independent assortment and crossing-over can generate genetic variation among the products of meiosis.
• Use chromosome models to demonstrate the activity of chromosomes during Meiosis I and Meiosis II.
• Relate chromosome activity to Mendelian segregation and independent assortment.
• Calculate the map distance of a particular gene from a chromosome's center for between two genes using an organism of your choice in a controlled experiment.
• Demonstrate the role of meiosis in the formation of gametes using an organism of your choice, in a controlled experiment.
• Compare and contrast the results of meiosis and mitosis in plant cells.
• Compare and contrast the results of meiosis and mitosis in animal cells.

Suggested Laboratory Experiments:

Resources:

• Chapter 13: Meiosis and Sexual Life Cycles, pp. 226–238
• Chapter 14: Mendel and the Gene Idea, pp. 239–260
• Instructor's Guide, pp. 167–199
• Student Study Guide, pp. 87–102
• Test Bank, pp. 146–170
• Lab Manual, pp. 161–188 and 189–246
• CD-ROM: Chapters 13 and 14 include narrated presentations, activities, and links to the Internet.

Pacing Guide:

• Chapter 13: Meiosis and Sexual Life Cycles—1 day
  The following activity will help students think about meiosis, linkage, making gene maps, and the mitosis and meiosis laboratory. Give 20 people each a length of paper about three inches wide and a foot long. You could use the paper on an adding machine. Write an allele symbol in the center of each piece of paper. Have both dominant and recessive alleles at each locus, and two copies of each allele. Now have the students line up in four rows such that the four alleles of any locus are at the same place in the row. For example:

  A	b	C	D	e
  A	b	C	D	e

  A	B	c	d	E
  A	B	c	d	E

  Have students hold their papers up so that they make a continuous strip of paper in each row. These are chromosomes in synapsis at prophase I of meiosis. Ask them to move apart at anaphase I, two strands to each pole.
  
  Now ask this "chromosome model" to form a cross over between B and C. One row with b C and one row with B c trade ends of the paper strip. Note the difference when anaphase occurs.
     A     b             C     D    Break the two strands.
     A     B             c     d   
  
  The person with b hands an end to the person with c. The person with B hands an end to the person with C.
  
  Now move apart in anaphase I as before. Note that the strands that traded ends will have to go to different poles than they may have gone before. Two strands will now be recombinant and two strands will be parental.
  
  There is another use for the person and paper chromosome model in the previous demonstration. Have a student walk back and forth in front of the chromosome model. At intervals say "stop." The student stops and makes a mark on the paper of one of the chromosomes at the point nearest to where the student with the marker is standing. Repeat this process 20 or 30 times. Now analyze where the marks are. Note that the farther apart the loci are, the more marks there are between them. In crossing over between genes, the farther apart the loci are, the more frequently will crossovers occur. This is the basis for constructing gene maps.
  
  The above activities will help the students understand the principles of the lab.
• Biology AP* Lab 3—2 days
  Practice identifying various stages of mitosis before doing this lab by using microscope images.
• Chapter 14: Mendel and the Gene Idea—2 days
  Have students separate into two separate groups based on whether they have a widows peak. Then have them separate into groups based on whether they have attached or detached ear lobes, the ability to roll tongues, and whether they taste or don't taste PTC. Help them conclude that there are endless subgroups of characteristics and if the separation process was complete that each person would be in a separate group with their unique characteristics.
• Block Scheduling
  Use half of a block for Meiosis and Sexual Life Cycles, one block for AP* Lab 3, and one and one half blocks for Mendel and the Gene Idea.

Key Words:

Suggested Exercises:
Critical thinking questions and end-of-chapter activities are included in these exercises.

1. Challenge Questions, p. 238 #1–2, p. 129 #1–2, and p. 146 #1–3
2. Science, Technology, and Society, p. 238 #1–2 and p. 260 #1–2
3. Genetic Problems, pp. 259–260 #1–20

Troubleshooting Tips/Error Traps:

• Focus students on metaphase of meiosis I and the lining up of a haploid number of tetrad. Have them focus on metaphase of meiosis II and the lining up of a haploid number of chromatids, and then they can relate the other phases to these. They need to understand the process and results of meiosis.
• It is best to get an extra culture of Sordaria to ensure success of the lab. It is important to have a few class days available to do the Sordaria part of the lab, because the culture must be at the right stage to see the mature asci.