Beacon Lesson Plan Library

Multiplication in Cells

Leon Gaither
Orange County Schools

Description

The students model cell division processes of mitosis and meiosis.

Objectives

The student knows that the body processes involve specific biochemical reactions governed by biochemical principles.

The student knows that body structures are uniquely designed and adapted for their function.

Materials

PER CLASS
-Models or diagrams of mitosis and meiosis
-Table showing stages and important events of mitosis and meiosis

PER STUDENT
-2 Black licorice sticks
-2 Red licorice sticks
-Napkin or paper towel
-Plastic zipper bag
-2 Pieces of plain paper
-Colored pencils or markers

Preparations

1. Cut licorice sticks in half.
2. Place 4 pieces of black licorice and 4 pieces of red licorice in a zippered bag with a napkin or paper towel.
3. Consider which students will work best together and devise a method to pair students.
4. Provide colored pencils or markers for students to record their observations.
5. Make a table of mitosis and meiosis so that students can see it.
6. Answers to discussion questions:
a. Mitosis: It remains the same.
b. Meiosis: It is reduced or cut in half.
c. In metaphase of mitosis, the chromosomes line up in single file in any order along the equator of the cell. In metaphase I of meiosis, the chromosomes line up in pairs on the equator.
d. Mitosis: Asexual reproduction, growth, replacement of damaged cells.
Meiosis: Sexual reproduction.
e. Both are cell division processes and require duplication of chromosomes or genetic material. Replication or duplication occurs before the chromosomes are visible.
f. Lineup of chromosomes in metaphase, number of cells produced, chromosome number in new cells.
g.
h. Six, 6.
i. Three, 3.

Procedures

1. Discuss with the students the stages of mitosis and meiosis using diagrams and models. Determine that the students have become familiar with events in both mitosis and meiosis before continuing the lesson.

2. Distribute cell division bags (zippered bags with licorice inside), pencils and markers, and napkins to students at their seats.

3. Tell the students that they have five minutes to demonstrate the cell division and replication processes of meiosis and mitosis, in order of occurence, to a partner using the licorice chromosomes.

4. Tell the students that the parent cell in each process will have two pairs of homologous chromosomes, one black pair and one red pair. (Be sure the students begin with the correct number of chromosomes so that they have the correct number of pieces remaining to show chromosomal replication. Ensure that the students create their products on the napkins as they will be allowed to eat their licorice at the conclusion of the activity.)

5. When step #3 is completed by all students: Tell the students that (working together to create one complete set) they have 30 minutes to diagram and write a description comparing and contrasting each of the processes they created using the pieces of plain paper, markers and/or coloring pencils provided.

6. Tell the students that once the diagrams and descriptions are completed, they are to display them in order on their desks. Tell the students that after the completion of the activity, they will be allowed to eat their licorice chromosomes.

7. As a wrap-up activity, the teacher and students discuss the answers to the following questions:
a. What happens to the chromosome number in mitosis?
b. What happens to the chromosome number in meiosis?
c. How does metaphase of mitosis compare to metaphase I of meiosis?
d. What are the purposes of each process?
e. What are the similarities (compare) in the two processes?
f. What are the differences (contrast) in the two processes?
g. How are both processes related to sexual reproduction?
h. If a cell undergoing mitosis has 6 chromosomes, how many chromosomes will be found in each daughter cell?
i If a cell undergoing meiosis has 6 chromosomes, how many chromosomes will be found in each gamete?

Assessments

How will you know that students have learned?
1. Observe the students as they manipulate the models.
2. Listen as students demonstrate the models to partners.
3. Listen to the discussions of questions.
4. Each student writes a description of one or both processes to be submitted for grading.
5. Students answer additional questions about chromosome number in resulting cells. (See Procedures, step 7, questions h and i.)

What do performance levels look like?
Students will:
1. Demonstrate mitosis.
2. Demonstrate meiosis.
3. Describe each step of each cell division and replication process.
4. Compare and contrast the two processes of cell division.
5. Create a diagram showing each stage of each process.

Extensions

1. Students can use their knowledge of mitosis and meiosis to explain the maintenance of chromosome number in reproduction of organisms.
2. Students can design models or diagrams of the cell division process using other materials.

Web Links

Web supplement for Multiplication in Cells
Biology

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