1 2 3 4 1. THE QUESTION How do materials get into and out of a cell? Even though they are very tiny, cells are complex living things. Cells must send out signals to communicate with other cells and bring in nutrients from the outside world. http://www.media.nih.gov/imagebank/display_search.aspx?id=652 Today you will answer the question above by exploring features of the cell membrane that allow it to act as a semi-permeable barrier. You will discover how the cell membrane helps the cell maintain homeostasis. http://www.media.nih.gov/imagebank/display_search.aspx?id=636 Photos from NIH Image Bank These materials are © 2012 K Maddox, Dulaney High School, all rights reserved. 5 6 Next 2. INFORMATION SOURCES 1 2 3 4 5 6 Next Let’s get started! Use the following resources to help you become familiar with the construction of the cell membrane: 1. 2. 1. 2. 3. Cell Membrane Play the animation to see an overview of the cell membrane. Step through the animation a SECOND time. As you do, draw the cell membrane in your notebook and label ALL of the parts. Phospholipids At this point you have discovered that one of the major components of the cell membrane are phospholipids. Draw a phospholipid in your notebook. Label the hydrophilic and hydrophobic sections. Test yourself: Visit the page, Construction of the Cell Membrane and click NEXT to go through each of the slides. As you work, match the membrane parts with their functions below. (record these in your notebook) When you reach the questions, make sure that you • Glycoprotein have answered all 10 correctly • Channel Protein before moving forward. • Pore Protein • Fibrous (Integral) • Cholesterol Parts http://www.media.nih.gov/imagebank/display_search.aspx?id=638 1. Allow ions and other polar molecules to pass through the membrane 2. Only found in animal cell membranes 3. Span the entire membrane and serve as a receptor for the cell. 4. Found on the surface of the membrane, they help identify the cell 5. Allow water molecules to pass through the membrane Functions These materials are © 2012 K Maddox, Dulaney High School, all rights reserved. 1 3. TYPES OF TRANSPORT 2 3 4 5 There two main ways that cells move materials in and out through the membrane! Some ways require energy and others do not. Compare Active and Passive transport of materials using the resources indicated below. HINT! If you right-click on the animations as they are playing you can un-check PLAY to stop and record information in your notebook. Passive Transport Active Transport 1. What is passive transport? 1. What is active transport? 2. What are the three forms of passive transport? a) O_________ 2. What are examples of active transport? b) D_________ c) F__________ D__________ • 3. Compare the molecules that can get through the membrane in passive transport to those that cannot. Watch this animation to see two types of active transport in action. 3. What are these two types called? 4. How are they similar? 5. How do they differ? 4. What is a concentration gradient? Watch this animation if you need a hint. 6. How do molecules move, relative to the concentration gradient, in active transport? These materials are © 2012 K Maddox, Dulaney High School, all rights reserved. 6 Next 1 2 3 4 5 6 Next 4. THE ASSESSMENT: CREATE A VENN DIAGRAM 1. 2. Create a Venn Diagram in your notebook (or using this Venn Diagram maker) that compares Active and Passive transport of materials across a cell membrane. 1. Show which processes do and do not use energy. 2. Indicate which direction molecules move relative to the concentration gradient for each type of transport. 3. Give examples of each type of transport. Check the rubric to be sure you have included all of the important details. Passive Transport http://www.media.nih.gov/imagebank/display.aspx?ID=113 These materials are © 2012 K Maddox, Dulaney High School, all rights reserved. Active Transport 5. ENRICHMENT ACTIVITIES 1 2 3 4 5 6 Next If you have finished early, you can explore active and passive transport in a little more detail and answer the questions below to earn some extra points. http://www.media.nih.gov/imagebank/display_search.aspx?id =111 Here are some web resources that may help you find answers to these questions: BrainPop for Active transport BrainPop for Passive transport Osmosis You can also go back to the resources from the previous slides for more links. Copy the box below onto your paper and draw a concentration gradient, where the concentration of molecules on the left is greater than that on the right. When, if ever, does diffusion of molecules end? Why is facilitated diffusion needed? What is the difference between a hypertonic and hypotonic solution? What is an isotonic solution? If a cell is placed in an isotonic medium, will there be net movement of water? http://www.media.nih.gov/imagebank/display_search.aspx?id=765 These materials are © 2012 K Maddox, Dulaney High School, all rights reserved. 1 2 3 4 5 6 6. TEACHER SUPPORT MATERIALS Teacher notes: This lesson is appropriate for the Cellular Biology Unit of the BCPS High School Biology curriculum. Students should be able to complete the activity in pairs during one or two class periods. Student computers will need access to the websites and animations linked in this presentation. Maryland State Curriculum Goal: Expectation 3.2 The student will demonstrate an understanding that all organisms are composed of cells which can function independently or as part of multicellular organisms. Indicator 3.2.1 The student will explain processes and the function of related structures found in unicellular and multicellular organisms. Assessment limits: Objective: Students will analyze parts of the cell membrane in order to identify structures involved in and characteristics of passive and active transport of materials in and out of living cells. transportation of materials (role of cellular membranes; role of vascular tissues in plants and animals; role of circulatory systems) waste disposal (role of cellular membrane; role of excretory and circulatory systems) feedback (maintaining cellular and organismal homeostasis - water balance All images from NIH Image Bank These materials are © 2012 K Maddox, Dulaney High School, all rights reserved. Rubric Venn Diagram Scoring Rubric Venn Diagram: Cell Membrane and Transport of Materials Teacher Name: Ms Maddox Points Points Points Points CATEGORY 4 3 2 1 Venn Diagram- Overall All aspects of Active and Passive transport are clearly indicated in the Venn Diagram. Diagram is clear and organized. One or two terms are missing. Several important points are missing and no comparison of similarities is made. Venn Diagram is unorganized and difficult to read. Two errors. Energy is not addressed in the Venn Diagram Several errors in movement of molecules. Movement of molecules relative to concentration gradient is not addressed. Energy Direction of molecule movement Examples Energy for Active and Passive transport One error in the is addressed correctly. requirement for energy. Direction of molecule movement, relative to the concentration gradient is appropriately labeled. One error in direction of movement. At least two examples are given for Only 1 example is Examples for only Examples of passive and active and passive transport. given for each type one type of transport active transport are not of transport. (passive or active) are addressed in the Venn given. Diagram. These materials are © 2012 K Maddox, Dulaney High School, all rights reserved.