As the students enter the room, they take out their journals and respond to the prompt:
Thinking about our activity yesterday, what are some of the key differences between mitosis and meiosis.
While the students work on the prompt, I circulate through the room to review their responses. This prompt is a direct review of the information the students discussed and wrote about for the previous class, so I expect detailed information. I also expect the students to be able to describe the types of cells in which each type of cell division occurs and to explain the product of each.
I ask for volunteers to share their responses with the class by having the first volunteer list a characteristic and then I ask another volunteer to either provide more information about that characteristic or to add a new characteristic.
After reviewing their journals, I lead a quick summary of the information from our cells unit and how it relates to our genetics unit. This helps to remind the students of the various connections that can be made in science. I do this by providing the students with a topic or term and ask them how it relates to mitosis. Some of the terms I use include DNA, replication, and nucleus. Our discussion helps to address NGSS MS-LS1-2 as we review the various structures and functions of the cell as they relate to the reviewed terms.
Once we have reviewed, I explain to the students that cells spend differing amounts of time in the different phases of mitosis. I tell the students that in order to have a better understanding of how much time cells spend in each phase, they will be completing an online activity. I then open the Mitosis Exploration document as I direct students to open the same document on their Chromebooks. I review the instructions with them and answer any questions they have.
This brief video provides an explanation of the website the students use for the activity.
As the students work on the activity, I circulate through the room checking on their work and asking them questions. Once the students get to the portion of the activity where they are identifying the phase that the cell is in, I ask them to justify their selections. For some students it is tempting to just click on choices for the labels instead of reading the information. Asking the students questions about their choices and having them explain the various structures that are evident in the picture of the cell helps to ensure that they are not just guessing at the answers. Asking students to justify their choices also helps me to address student misconceptions and help students further develop their understanding of the topic. Completion of the chart included on the worksheet addresses NGSS SP5 as students find percentages while viewing the pictures of the cells helps to address NGSS Cross Cutting Concept Structure and Function MS1 as students must examine the relationship between the microscopic elements of the cell in order to determine the phase it is in. This student work sample is representative of the work I expect from students.
The pacing of this activity varies greatly for the students. Some of the students are very familiar with the structures of the various phases, while other students are still struggling. I make sure that early finishers have something to work on by providing them with the Gel Electrophoresis activity. At this point in the unit, we have not yet explored gel electrophoresis, but will discuss it in an upcoming lesson. Students are able to work independently through this simulation without having a deep understanding of the concept.
At the end of class, I duplicate the chart from the worksheet on the SMARTBoard and we complete the chart as a group. I typically ask one student to tell the class the number of pictures for one phase and then have another student tell us the percentage of time the cell spends during that phase. Once we have completed the chart, we discuss the percentages as a class. I also have the students reference a diagram in their textbook that shows a different representation of the amount of time the cell spends in each phase.