Modeling Mitosis

Before Strategy/Engage: 100 minutes (Day 1 and 2)

1. The teacher should give each student a copy of the Pre-/Post-Test – Mitosis. The teacher should give students approximately ten to fifteen minutes to complete the pre-test. The teacher should stress to students that the purpose of the pre-test is to demonstrate the student’s background knowledge about the concepts of osmosis and diffusion.

2. After students complete the pretest, the teacher should check students’ answers to determine their current knowledge base of the concepts using the Pre-/Post-Test – Mitosis Answer Key. Alternatively, the teacher could allow students to check their own paper or check a partner’s paper.

3. After the students have completed the pretest, the teacher should post the following “Questions to Ponder” on the board. The teacher should allow student volunteers to share their answers, then record student responses on the board.

• How does a human being grow from a single fertilized cell into an individual containing billions of cells?

Possible Answer: Cells increase their number through a process called cytokinesis or cell division. Cell division is preceded by nuclear division or mitosis.  The genetic information of the parent cell is reproduced exactly in each daughter cell, whereas division of the other cell components is not exact.

• Do all of the cells of the body look like one another? Do they perform the same jobs?

Possible Answer: There are many different types of cells in the body which serve many different functions. A nerve cell which conducts electrical messages looks very different from a cheek cell. Cheek cells are a type of epithelial tissue which are tightly arranged to help protect against bacterial invasion.

• Do all cells of the body contain the same genetic information?

Possible Answer: All cells in the body with the exception of the egg and the sperm have identical copies of an individual’s genetic information. Different genes are activated in different cell types.

• How is the genetic blueprint that makes you who you are transmitted continuously from one cell to the next?

Possible Answer: The consistent transmission of genetic material from one cell generation to the next is accomplished through DNA replication during Interphase and division in the process of mitosis. This nuclear replication and division occur billions of times with great accuracy as a human being grows and develops.

• How long does it take for one parent cell to become two daughter cells?

Possible Answer: In humans, rapidly dividing cells such as skin and gut divide as often as once a day. Other cells, such as brain and nerve tissue, rarely divide in adult cells.

• Are cells alive?

Possible Answer: Yes, they are the smallest units of life. They are considered to be living because they are capable of respiration, nutrient intake, the release of waste materials, reproduction of themselves, movement, responsiveness and other processes which are characteristic of other living things.

• What is a cell anyway?

Possible Answer: Cells are sometimes referred to as the basic units of life; they are small compartments in your body which house your DNA and perform all the essential tasks to sustain life. They are surrounded by a cell membrane, contain a nucleus surrounded by a nuclear membrane and have many other organelles performing various functions.

4. For the next portion of the lesson, students will need access to a technology device. Students should visit the Virtual Compound Microscope website and complete the online tour to review the correct usage of a compound microscope.

5. For the next activity in the lesson, students will need to be divided into collaborative groups of approximately four students each. Each student will need a copy of The Human Cheek Cell Lab Sheet. Each group will need the required materials for the lab activity. Students should follow the procedures listed on the lab sheet. This lab sheet will also direct students to collect data during their investigation and answer reflection questions at the conclusion of the lab.

During Strategy/Explore & Explain: 100 minutes (Day 3 and 4)

1. For the next portion of the lesson, students will need to be divided into eight collaborative groups. Each student will need a copy of Student Lab Guide 1-Modeling Mitosis\. Each group will need the required materials for the lab activity. Students should follow the procedures listed on the lab sheet. This lab sheet will also direct students to collect data during their investigation and answer reflection questions at the conclusion of the lab.

2. Students will continue to work in eight collaborative groups during the next lab activity. Each student will need a copy of Student Lab Guide 2-Mitosis Observation. Each group will need the required materials for the lab activity. Students should follow the procedures listed on the lab sheet. This lab sheet will also direct students to collect data during their investigation and answer reflection questions at the conclusion of the lab.

After Strategy/Explain & Elaborate: 50 minutes (Day 5)

1. After all groups have completed the lab activities on mitosis, the teacher should lead a class discussion among all of the groups to compare each group’s data.

Note: If the teacher identifies that students need additional review before the summative assessment, the teacher may show students the attached Mitosis Presentation to review the concepts demonstrated during the lab activities (see attached PowerPoint presentation).

2. The teacher should give the students the Pre-/Post-Test – Mitosis, that students completed as a pre-test at the beginning of the lesson. The teacher should explain to students that this post-test will allow students to demonstrate the knowledge they acquired during the lab activities.