Bio 111 Study Guide Chapter 5 Membrane Transport and Cell Signaling

Transcription

1 Bio 111 Study Guide Chapter 5 Membrane Transport and Cell Signaling BEFORE CLASS: Reading: Read the whole chapter from pp There are many great figures in this chapter. Make sure you study all of them as you read the text. In particular, study Figure 5.8. Many students find this concept confusing, but may help to view it as a process with steps like the book shows it. Definitions: selective permeability amphipathic fluid mosaic integral proteins peripheral proteins glycolipid glycoprotein transport protein diffusion concentration gradient passive transport osmosis isotonic hypertonic hypotonic osmoregulation facilitated diffusion active transport

2 membrane potential electrogenic pump proton pump cotransport exocytosis endocytosis phagocytosis pinocytosis hormones reception transduction signal transduction pathway response ligand receptor G-protein-coupled receptor (GPCR) G protein ligand-gated ion channel phosphorylation protein kinase protein phosphatase second messengers

3 Questions/Problems: 1. After studying Figure 5.2, 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. 2. Use each of the words below once to label a part of the figure. Receptor Cytoplasm Relay molecules Transduction Response Reception Activation of cellular response Signaling molecule (ligand) Plasma membrane

4 DURING CLASS: Plasma Membrane Functions: Structure: Fluid Mosaic Model Membrane Lipids Membrane Proteins Peripheral proteins Integral proteins Major Functions:

5 Membrane Carbohydrates Membrane Synthesis and Sidedness Membrane LIPIDS are made in the. Membrane PROTEINS are made in the. Membrane CARBOHYDRATES are added in the. Selective Permeability Cross easily: Do not cross easily: Some only through transport proteins: Membrane Transport Processes Concentration gradient Diffusion Osmosis Facilitated Diffusion

6 Active Transport Animation Active Transport Cotransport Tonicity of Solutions Isotonic Hypertonic Hypotonic In Animal Cells: In Plant Cells: Videos Turgid Elodea Cells & Plasmolysis in Elodea Example of Adaptation: Video Paramecium Contractile Vacuole

7 Membrane Potential Membrane potential Electrogenic pump Proton pump Sodium-potassium pump Other Transport Processes Exocytosis Endocytosis Phagocytosis Pinocytosis Receptor-mediated endocytosis Animation Membrane Transport

8 Local and Long-Distance Cell Signaling Local Signaling: Long-distance Signaling: Regulation of Proteins Protein Kinase Protein Phosphatase Signal Transduction Pathways Reception G Protein-Coupled Receptors (GPCRs):

9 Ligand-gated Ion Channel Receptors: Intracellular Receptors: Transduction Phosphorylation Cascade: Second Messengers: Response In the nucleus: In the cytoplasm: **Take Away Concept** The plasma membrane is a very dynamic part of cells. It is critical to a cell functioning properly, including the transporting of molecules and the receiving of messages.

10 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?

11 4. You learned in Chapter 4 that animal cells have 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.

12 9. Nerve growth factor (NGF) is a water-soluble signaling molecule. Would you expect the receptor for NGF to be intracellular or in the plasma membrane? Why? 10. Fill in the blanks: A. When a kinase phosphorylates another protein, this usually the protein. B. Steroid hormones are which allows them to easily cross the plasma membrane. C. Neurotransmitters are an example of signaling molecule. D. A G protein is when GTP is bound to it. E. function as long-distance signal molecules in both plants and animals. 11. Briefly describe how each of these receptors receives its signal and passes it on to the cell. a. G Protein-coupled Receptors: b. Ligand-gated Ion Channel Receptors: c. Intracellular Receptors (steroid):