THE EUKARYOTIC CELL CYCLE AND CANCER: AN OVERVIEW ABOUT THIS WORKSHEET This worksheet complements the Click and Learn “The Eukaryotic Cell Cycle and Cancer” and is intended as a straightforward introduction to the cell cycle and how it relates to cancer. For a more comprehensive student worksheet, please see the in-depth version. PROCEDURE Read through the Click and Learn at (http://www.hhmi.org/biointeractive/eukaryotic-cell-cycle-and-cancer) to learn about the cell cycle. Answer the questions below. Click on the “Background” tab on the right side. Read the information and watch the videos. Click on the purple section labeled “Cell Cycle Phases” as well as the words “Mitosis” and “Interphase” to read an overview of the cell cycle. You can also click on the various phases. Cells go through periods of growth and division. Cell division occurs during ___. The rest of the cell cycle is called interphase, during which _________________. Fill in the details about what happens during the three phases of interphase labeled in the diagram. In general, what is the purpose of a checkpoint in the cell cycle? Click on the “Background” tab on the right side. Read the information and watch the videos. 1. Why is cell division important for both unicellular and multicellular organisms? 2. Why does cell division remain important to an adult organism even after it is fully developed? 3. Cells divide, differentiate, or die. What is differentiation? 4. What is apoptosis? What is its purpose? 5. What are cell cycle regulators? 6. What happens if cell cycle regulators don’t function properly?
The Correct Answer and Explanation is:
The eukaryotic cell cycle is a crucial process that regulates the growth, division, and differentiation of cells, impacting both unicellular and multicellular organisms. Here’s an overview of the concepts based on the worksheet and questions:
- Why is cell division important for both unicellular and multicellular organisms? Cell division is essential for unicellular organisms because it is the means by which they reproduce. In multicellular organisms, cell division plays a key role in growth, tissue repair, and maintenance. It allows an organism to grow from a single fertilized egg into a complex organism with specialized cells. Additionally, it helps replace cells that die naturally or due to injury.
- Why does cell division remain important to an adult organism even after it is fully developed? Even in fully developed organisms, cell division continues to be vital for the renewal of tissues, repair of damaged cells, and maintaining homeostasis. For example, cells in the skin, blood, and digestive tract are constantly being replaced because they have limited lifespans. Additionally, the immune system depends on cell division to produce new cells to fight infections.
- Cells divide, differentiate, or die. What is differentiation? Differentiation is the process by which unspecialized cells (like stem cells) develop into specialized cells with distinct functions. For example, stem cells can differentiate into muscle cells, nerve cells, or skin cells. This process is essential for creating the diversity of cell types needed in multicellular organisms.
- What is apoptosis? What is its purpose? Apoptosis is programmed cell death. It is a natural process that removes damaged or unnecessary cells, preventing them from becoming dysfunctional or potentially harmful. For instance, apoptosis plays a role in eliminating cells that are infected with viruses or have the potential to become cancerous, ensuring the organism’s health.
- What are cell cycle regulators? Cell cycle regulators are proteins and enzymes that control the progression of the cell cycle. These include cyclins, cyclin-dependent kinases (Cdks), and tumor suppressor proteins like p53. They ensure that cells progress through the different phases of the cycle at the right time and that any errors are corrected.
- What happens if cell cycle regulators don’t function properly? If cell cycle regulators fail to work properly, cells may divide uncontrollably, leading to mutations and the development of cancer. For example, malfunctioning tumor suppressors or overactive proto-oncogenes can result in cells bypassing checkpoints, leading to tumor formation. This is a hallmark of cancer development.
In general, checkpoints in the cell cycle are important because they ensure that each phase is completed correctly before the next one begins, thus preventing errors during DNA replication and division. If checkpoints fail, cells may replicate damaged DNA, contributing to diseases like cancer.
