Unit 2 introduces the concept that the body is composed of a community of cells. These cells are all ‘normal’ until mutations cause them to behave abnormally and become cancer cells. This unit describes the function of normal cells by outlining key aspects in the life of a normal cell – how normal cells are born, grow up and get a job, communicate with their friends, grow old, and die. All these aspects are typically affected in cancer cells.
Lesson 1
Lesson 2
Lesson 3
Lesson 4
Lesson 5
Lesson 1
What type of normal cell is most vulnerable to becoming a cancer cell, and why?
In this lesson, students will examine how organs are made of tissues, which are composed of different cell types. They will learn that most organs are lined with epithelial cells which perform the main function of the organ while being supported by the stromal cells. They will examine why most cancers originate from epithelial cells. Students will perform an activity in which they identify which types of epithelial cells are present in different organs, and also identify the location of the epithelial layer in relation to the stroma in different tissues.
Objectives
– Describe the relation-ship of organs to tissues to cells. – Explain the function of epithelial cells within organs. – Explain why epithelial cells are particularly vulnerable to carcinogens – Explain why most cancers originate from epithelial cells.
Activities
Epithelial cell histology, function and exposure to carcinogens.
Worksheet & Video: Watch video about mitosis and answer questions on worksheet.
Lesson 2
How is replication controlled in a normal cell and disrupted in cancer?
In this lesson, students will begin the process of examining the cell cycle, and how it is affected in cancer. Students will learn how the cell cycle regulates when and where a cell is ‘born’ during the process of mitosis, and will then explore the behind-the-scene steps that occur to prepare the cell for mitosis. Students will perform a small group activity to explore the functions of drivers and brakes to progress and slow down the cell cycle leading to mitosis. These drivers and brakes are commonly mutated during cancer, leading to a loss of control of the cell cycle.
Objectives
– Describe the significance of interphase during the cell cycle. – Explain how driver proteins move the cell cycle forward. – Describe how checkpoint proteins inhibit cell cycle progression. – Explain how drivers and checkpoint proteins can lose control of the cell cycle, leading to unregulated cell growth.
Activities
Game to simulate cell cycle progression and the role of drivers and checkpoint proteins.
Other Materials – Cell cycle game boards – Cell cycle dice
Homework
Worksheet: Reading on how chemotherapy drugs interfere with the cell cycle and answer questions.
Lesson 3
How do cells normally act as part of a community and become isolated in cancer?
Students will use the wound-healing process to examine how extracellular signals can tell cells when to start dividing and when to stop dividing. Students will become familiar with the idea of a signal relay system and explore its main components — the extracellular signal, the receptor, the transduction protein and the transcription factor. Students will explore a simulation in which the signaling that occurs between stromal cells and epithelial cells during wound healing is able to generate new cells that can repair a wound. They will also see how mutations that affect the signal relay system can lead to uncontrolled cell division and cancer.
Objectives
– Explain how the extracellular signals that promote or block cell proliferation cooperate to regulate wound healing. – Describe the function of the main components in a cell-signaling cascade: extracellular signal, receptor, transduction proteins and transcription factor. – Predict the effects of mutating a cell-signaling cascade on cell growth and death in wounded tissue.
Activities
Computer simulation of signaling pathways that promote and block cell proliferation during wound healing
Worksheet: Reading about how cancer uses the wound healing pathway to metastasize and answer questions.
Lesson 4
How are cell activities controlled in a normal cell and disrupted in cancer?
In this lesson, students will investigate how it is possible for every cell in the human body to contain identical DNA, and yet look and behave so very differently. Students will learn that, although every cell has identical genes, not every cell transcribes and translates every gene into protein. Rather each cell selects which genes it will express in order to perform its specific function. This process of specialization, called differentiation, is important for maintaining the order and structure of different tissues within organs. Students will perform a small-group activity to examine the types of genes that get shut on and off in different cell types under normal conditions so they can functionally specialize, and they also get to see how this control of gene expression is disrupted in cancer cells.
Objectives
– Explain how different cells can perform different functions even though they carry the same DNA. – Explain the term “differentiation” and be able to describe the roles of “stem cells” and “terminally differentiated cells”. Explain how gene expression is controlled by transcription factors. Explain how gene expression is controlled by “opening” and “closing” DNA.
Activities
Interrupted case study on variations in gene expression in different cells
Worksheet: Reading on cancer stem cells and answer questions.
Lesson 5
How is cell death controlled in normal cells and disrupted in cancer?
In this lesson, students compare/contrast the two different pathways normal cells use to die. These pathways, called apoptosis and necrosis, have different functions, and apoptosis, which can be thought of as self-destruction or cell suicide is a normal process that happens to end the life of damaged or old cells. Apoptosis is essential to maintain normal tissue health. When and where apoptosis occurs is tightly regulated by pro-death and pro-survival signals, and students will see how that balance gets disrupted in cancer. Students play the Apoptosis card game to simulate how the interaction between these two types of signals determines the fate of the cell.
Objectives
– Explain why apoptosis is an essential part of the dynamic equilibrium that exists for all cells. – Describe how cell survival is a dynamic process that requires extracellular signals. – Explain how the balance between apoptosis and survival is shifted in cancer cells.
