The Cell Walk (Part 3/3)
Lesson 5 of 5
Objective: Students will construct a gym-size model of a skin cell. They will explain how the endomembranous system works and how the organelles work together to keep the cell alive.
Today is the day! Students give tour of their gym-sized cell. In this lesson, I describe the layout of how we produced the cell walk. It is a presentation day in which organelle teams give tours all day long. They give tour to all of the high school and middle school science students during their science periods. Here is an overview of what students will learn today.
The student tour group will enter from the side gym door. The first organelle they visit will be the cytoskeleton. The student presenter will explain the structure and function of the cytoskeleton. She uses a flipchart of images that was made from the powerpoint she developed for this presentation. It contains presenter notes on one side that only she can see. It also has color slides that the students going through the tour can see. She and the teacher will question the student group. The group will respond. After showing the model of the cytoskeleton, she will give her object lesson and direct the student group to the next organelle--the nucleus. Here is a copy of her cytoskeleleton presentation.
The same tour group will step into the nucleus which is located next to the cytoskeleton. The nuclear structure is a modified 8 man tent that has DNA that is partially supercoiled with histones. The organelle team for this station explain the structure and function of the nucleus using a flipchart and the tent in which the group is standing. The organelle team have chosen a large exercise ball to represent the nucleolus, large and small foam plates to represent the incomplete ribosomes, and a piece of paper with envelope to represent the mRNA. Both presenters and teacher should question the student group. Next, the presenters will had students play a short game in which the wrap two joined pieces of tow robe with their hands to represent the chromosome supercoiling. After the game, students will be directed to the next organelle--the endoplasmic reticulum. The organelle tour guides send the student tour group on with the envelope mRNA as their object lesson. Throughout the tour, it is important to remind students of the limitations of the model.
The tour group will step into the Endoplasmic Reticulum which is connected to nucleus. This is an enclosed maze and a tight squeeze. The organelle team will explain the structure and function of both the smooth and rough ER. They also have a flipchart. The organelle team pays extra attention to the difference between the Rough and Smooth ER. Both presenters and teacher question the student group about differences and similarities in light of the current research. Next, the presenters will present a short object lesson where they ask what the tour group received from the nucleus. The tour group exchanges their mRNA envelope for a packing peanut that is supposed to represent an unmodified protein. This packing peanut is placed into a ziplock baggie that represents the vacuole. After the object lesson, students will be get onto scooters so that they will be on vacuoles. They are directed to the next organelle--the Golgi Apparatus. (Note: students realized that they did not have enough scooters for one of the classes. They modified their model and used black trash bags as vacuoles for that set of tour groups.)
The Golgi Apparatus
The Golgi Apparatus is located a short distance from the Endoplasmic Reticulum. The tour group will be met outside the Golgi apparatus and the organelle team will complete the first part of their presentation. The organelle team will explain the structure and function of the Golgi Apparatus. Like the other teams, they will also have a flipchart. The tour group will get off of their scooters and enter a 3 room tent which will represent the Golgi Apparatus. Students will enter the tent on the left side. The organelle team will explain the difference between in the cis- and trans-cisternae while leading the tour group through the 3 man tent. In the main room of the tent, the tour group will play their game in which they modify the structure of a tower of Legos. For the object lesson, students will exchange their packing peanut for a peanut butter cup. Students will receive a second object lesson: a shipping label that will send them to the lysosome. Students will exit the right side of the tent. Presenters and teacher will question the students on the outside of the tent. Students will return to their scooters and ride on scooters to the lysosomes via the mitochondria and peroxisome. Students will briefly stop on the outside of the Golgi Apparatus to view a budding vacuole.
The tour group will travel to the peroxisome in search of the lysosome. The peroxisome is a dining fly that is next to the mitochondria. The tour group and presenters will remain outside of the structure. The organelle team will also have a flipchart. (Note: This student work example shows how students included their presenter notes.) The organelle team used multiple colors of cups to represent the enzymes in this organelles. The crystalline structures was made by stacking cups in an orderly fashion. Presenters will have students play a game in which they demonstrate the breakdown of hydrogen peroxide by catalase. Students retain the oxygen as their object lesson. The water stays with the peroxisome. Then the tour group will move to the mitochondria. Throughout the tour the teacher tour guide will not only help redirect the organelle team to help them give the best presentation possible, but also evaluate the organelle teams' presentations.
The tour group will stay on their scooters, but stop by the one-man tent that represents the mitochondria. The tour group and presenters will remain outside of the structure. They will also have a flipchart. There are several specific structures within the tent as noted by the presenters (i.e. mitochondrial DNA is a diving ring, matrix membrane is a piece of fabric, and the ribosomes are small and large plates). Teacher and presenters will question the tour group. The teacher encourages the students to look back at where they have been. She points out several places where the cell model has some flaws. The teacher also asks the tour group to compare the interior of the mitochondria to the interior of the nucleus. The presenters will give their object lesson which is a jelly bean and then the tour group will move to the lysosome.
The tour group passes several different sizes of trash cans which are located near the exit of the gym. These are the lysosomes. The organelle team will explain how the structure and function of the lysosomes using their flipchart. For their object lesson, they check the mailing label from the Golgi Apparatus to ensure there is no damage to them. One individual in the tour group either does not have a mailing label or her or her mailing label is damaged. The tour group and organelle team play a game to demonstrate phagocytosis and how damaged or unwanted items are captured and destroyed by the lysosomes.
Teacher and student tour group will exit the gym. Student tour group will sit in the hall of the middle school. Students will quietly journal in the lab notebook explaining the relationship between the object from the object lessons and the organelles. Students will turn in their notebooks as they leave.