• Observe students as they work to arrange the mitosis images in the proper order.
• Make sure all group members are participating in the activities.
• Assess their understanding by asking them the reasons for their sequence of the mitotic phases.
• Observe students as they work on the Sequence of Mitosis Phases worksheet.
• Observe and assist students as they progress through the hands-on activity.
• Collect the reading comprehension assignment for individual assessment of an understanding of mitosis.
• Exit ticket: Write the phases of a cell’s life cycle on the board, out of order. Have students write them on the exit ticket, cross off the one that is not a part of mitosis, and number the remaining phases of mitosis in the correct order. (Interphase does not belong. Correct order: prophase, metaphase, anaphase, telophase.)

Note: While mitosis is presented in this lesson as a four-phase process (i.e., prophase, metaphase, anaphase, and telophase), some biologists divide mitosis into five phases, with prometaphase between prophase and metaphase.

Preparation: Have index cards ready to distribute to students upon entering the class. Label a set of cards A, B, C, and D for each cooperative learning group. Also, prepare packets in a large envelope for each group that contains: Mitosis Pictures, Inquiry Slips, and Phases of Mitosis Directions (S-B-4-2_Mitosis Pictures.doc, S-B-4-2_Inquiry Slips.doc, and S-B-4-2_Phases of Mitosis Directions.doc).

Give a brief introduction to mitosis. Write the following notes on the board (or project them onto a screen with an overhead projector), and instruct students to copy them. Read each note aloud before you present it on the screen:

1.   “Mitosis is the nuclear division of a nonreproductive eukaryotic cell.

2.   Mitosis occurs in eukaryotic (containing a nucleus and membrane-bound organelles) cells.

3.   Mitosis is often called nuclear division because it results in two duplicate cells from a single cell.

4.   In the cell cycle, mitosis follows interphase and precedes cytokinesis.”

Hand each student an index card with a letter on it. Once all students have received their cards, you can begin the lesson by asking students to form groups according to the letters on the cards. (i.e., all students with the letter A should be in one group, etc.).

Let students know that the objective of this activity is to use the pictures to predict the sequence of mitosis. Explain to the class that each group will receive a packet of pictures, inquiry slips, and directions (S-B-4-2_Mitosis Pictures.doc, S-B-4-2_Inquiry Slips.doc, and S-B-4-2_Phases of Mitosis Directions.doc). Each group member should have one inquiry slip for each picture in the packet. It may be helpful to demonstrate the process by displaying the picture, inquiry slip, and discussion form on the board.

Instruct students to take out the pictures, read the directions, and complete the inquiry slips. Then, allow students approximately 3 minutes to place the pictures in sequential order faced down. Let them know that this is only a prediction at this point.

Observe to make sure all groups are finished. Have the groups turn over their pictures and discuss the reasons as to why they placed their pictures in a specific order. Do not reveal the correct sequence yet.

Hand out the Sequence of Mitosis Phases worksheet (S-B-4-2_Sequence of Mitosis Phases and KEY.doc) and have students complete the sheet. This activity should take 5–10 minutes.

Give students the correct answers and proper sequence for the phases of mitosis. Allow them to label and reorganize their pictures in the correct sequence and glue/tape them on unlined paper with the appropriate labels. They define this as the phase in which the nuclear envelope breaks down so there is no longer a recognizable nucleus. Some mitotic spindle fibers elongate from the centrosomes and attach to kinetochores, which are protein bundles at the centromere region on the chromosomes where sister chromatids are joined.

Hand out the Reading Comprehension Assignment (S-B-4-2_Reading Comprehension Assignment and KEY.doc) and have students complete it. Set a time limit of about 15 minutes for this assignment.

Extension:

• Students who might need an opportunity for additional learning can create mitosis flash cards that have the phase name on one side, and a concise description of the phase on the other. Practice putting them in order using the phase name side and the phase description side. Practice saying the description while looking at the name side and practice saying the name while looking at the description side.
• Students who might need an opportunity for additional learning can come up with mnemonic devices for the phases (e.g., during metaphase chromosomes are in the middle, during anaphase chromosomes move apart).
• Students who might need an opportunity for additional learning can go to the following Web sites and view the mitosis animations:
• www.cellsalive.com/mitosis.htm
• www.johnkyrk.com/mitosis.html

• Students who may be going beyond the standards can go to http://www.biologycorner.com/flash/mitosis.html, read the directions, and complete the “Mitosis in Real Cells” activity. In addition to the instructions given on the site, have students sketch and write a description of the highlighted portion of each cell view.