Bio 111 Study Guide Chapter 7 Membrane Structure and Function BEFORE CLASS: Reading: Read the whole chapter from p. 124 138. Note the differences between Figures 7.2 and 7.3. We have come a long way in what we know about the structure of plasma membranes! Study Figure 7.7. You need to know and understand the basic structure and functions of all these membrane proteins. They are important and will be brought up throughout the semester. Also study Figure 7.9. A lot of students find this concept confusing, so spend some time studying this figure and its descriptions about the synthesis and sidedness of membranes. Definitions: selective permeability amphipathic integral proteins peripheral proteins glycolipid glycoprotein transport protein diffusion concentration gradient passive transport osmosis isotonic hypertonic hypotonic osmoregulation facilitated diffusion
active transport membrane potential electrogenic pump cotransport exocytosis endocytosis ligand phagocytosis pinocytosis Questions/Problems: 1. After studying the differences between Figures 7.2 and 7.3, use a pencil to sketch the plasma membrane. Start with a phospholipid bilayer. Then add some transmembrane or embedded proteins. Last, add some cholesterol molecules, extracellular matrix, and microfilaments. Label all these parts. Color it, if you want.
DURING CLASS: Plasma Membrane Functions: Structure: Membrane Lipids Membrane Proteins Peripheral proteins Integral proteins Major Functions:
Membrane Carbohydrates Membrane Synthesis and Sidedness Membrane LIPIDS are made in the. Membrane PROTEINS are made in the. Selective Permeability Cross easily: Do not cross easily: Some only through transport proteins: Membrane Transport Processes Concentration gradient Diffusion Osmosis Facilitated Diffusion
Active Transport Cotransport Tonicity of Solutions Isotonic Hypertonic Hypotonic In Animal Cells: In Plant Cells: Video Plasmolysis Example of Adaptation:
Membrane Potential Membrane potential Electrogenic pump Proton pump Sodium-potassium pump Other Transport Processes Exocytosis Endocytosis Phagocytosis Pinocytosis Receptor-mediated endocytosis Animation Membrane Transport **Take Away Concept** The plasma membrane is a very dynamic part of cells that is critical to a cell functioning properly.
AFTER CLASS: Questions/Problems: 1. Which of the following is not a component of the plasma membrane? a. phospholipids b. DNA c. cholesterol d. proteins e. all of the above are part of the plasma membrane 2. Which of the following types of amino acids would most likely be present in the transmembrane part of an integral membrane protein? a. a charged amino acid b. a polar amino acid c. a special amino acid d. a hydrophobic amino acid e. any of the above, with no preference 3. The figures on the right illustrate passive and active transport across a plasma membrane. Use them to respond to the following questions (a-c). a. Which section(s) represent facilitated diffusion? How can you tell? Does the cell expend energy in this transport? Why or why not? What types of solute molecules may be moved by this type of transport? I. II. III. b. Which section(s) show active transport? List two ways you can tell. c. Which of these sections are considered passive transport?
4. You learned in Chapter 6 that animal cells make an extracellular matrix (ECM). Describe the cellular pathway of synthesis and deposition of an ECM glycoprotein. 5. What types of molecules have difficulty crossing the plasma membrane? Why? 6. What types of molecules easily diffuse across the plasma membrane? Why? 7. Without looking at your book or your notes, describe and draw what would happen to a plant cell and a red blood cell if it was in each of these solutions: hypotonic, isotonic, and hypertonic. 8. If a marine algae cell is suddenly transferred from seawater to freshwater, the algae cell will initially a. lose water and decrease in volume. b. stay the same: neither absorb nor lose water. c. absorb water and increase in volume.