NESTED STUCTURE 3
TITLE: Normal cells and cancer cells exploration
There will be a benchmark lesson to introduce the characteristics of cancer. Students will learn that despite the fact there are many different types of cancer, it is still possible to list certain general characteristics. Cancer is a cellular disorder, with these general characteristics. First, cancer cells experience uncontrolled and disorganized growth. Normal cells only divide about 50 (fifty) times before they die, but cancer cells enter the cycle of dividing and reproducing, over and over again and never differentiate. In tissue cultures raised in labs, cancer cells lack the contact inhibition exhibited by normal healthy cells. This means, normal healthy cells stop reproducing when they contact each other, or the sides of a culture bowl. Normal cells in a tissue culture grow in only one layer because they adhere to the glass bowl and stop dividing once they make contact with their neighbors. Cancer cells have lost all restraint and grow in multiple layers, most likely because of cell surface changes. In the body, a cancer cell divides to form a growth, or tumor, that invades and destroys neighboring healthy tissue. Second, Cancer cells detach from the tumor and spread around the body. Cancer cells also tend to be motile. After traveling through the blood or lymph system, cancer cells start new tumor elsewhere in the body. This process is called metastasis. If the original tumor is found before metastasis has occurred, the chances of sure are greatly increased. This is the rationale for early detection of cancer. In fact, sometimes a person isn't even considered to have cancer unless metastasis has occurred. Benign tuners are those that remain in one place; malignant tumors are those that metastasize. After this short lesson, the teacher will present the students with diagrams showing normal and cancerous cells. Students will be asked to note the differences between the healthy cells with cancerous cells.
The exploration will be based on the comparison of the cells. If needed, the teacher could review prior information acquired in the last classes, especially in lesson 1.2 which was examine the tumors and normal tissues
The teacher should also place emphasis on the cell theory tenet that cells come from cells Students will be working in groups of 2-4.
OBJECTIVES: • Students will be able to recognize normal cells and cancerous cells. • Students know to the characteristics of cancer cells in general and in they own terms; they will not be required to know the exact definition of each one of them Students will be able to note that normal cells growth are regulated and cancer cells growth is not.
• Students will be able to identify some part of the cells which are the cell membrane, the cytoplasm and the nucleus and their differences in comparison to normal cells Students will be able to draw the cells that they will look at under the microscope.
MATERIALS: 1. Copies of diagrams (provided) 2. Microscopes 8-12 3. Prepared slides of normal and cancerous colon and lung (could be purchased through a Biological Supply Company). Teacher could use the copies of the slides provided if slides aren’t available. 4. 5-7 Computers with internet access 5. Classroom conducive for discussion 6. Copies of microscope Activity part I (provided)
PREPARATION: In order to carry this lesson successfully, the teacher should have some information and ideas on the topic of cancer. It will be better for the teacher to have more specific information on the types of cancer that will be covered in class. The web link to the slides provided with this lessons are on colon and lung cancer; but they should not be limited to them. The following websites are suggested to find accurate and helpful information on the topic of cancer in general, the three major causes of cancer, which are genes, environment and viruses. The teacher could also find specific information on cancer of their choice. For general and specific knowledge about cancer: http://www.cancerhelp.org.uk/default.asp this site could also be shared with students
TIME: 45 minutes
• The teacher should go over the characteristics of cancer cells and go over what the students have learned in lesson 1.2 for example • Exploration activities: Have students work in groups of 2-4 with the microscopes. If the microscopes are not available, the exploration could be done using the websites provided on the sheet labeled “Diagram”. • Diagram • Have students complete the Microscope activity: cooperative learning part I (worksheet provided) • Slides provided • This is also the best time to help the students to understand the concept that each type of cancer is separate from other types of cancer and should not be lumped together but there are commonalities. • Discussion • . I would also copy the images onto a word document, annotate them help kids focus on the right structures (with arrows) and provide a worksheet to go along with it. And then have a discussion.
ASSESSMENT: An informal assessment can be done when the teacher is walking around and observing students while they are working in groups The assessment would be the completed the microscope activity part I by the end of the class graded by the teacher. Without any labels teacher could put the slides on the microscope and have students identify what they are looking at. The teacher can set up the microscopes with each different slide on them and have the students identify them
Supplementary websites Teachers: http://www.chemcases.com/cisplat/cisplat19.htm
Cancer cells proliferation http://ae.medseek.com/adam04/images/en/9780.jpg
Healthy skin versus skin cancer http://www.humanillnesses.com/original/images/hdc_0001_0003_0_img0239.jpg