Chapter 8 Cellular Transport and the Cell Cycle In your textbook, read about osmosis: diffusion of water. Reinforcement and Study Guide Section 8.1 Cellular Transport Complete the table by checking the correct column for each statement. Statement Isotonic Hypotonic Hypertonic Solution Solution Solution 1. Causes a cell to swell 2. Doesn t change the shape of a cell 3. Causes osmosis 4. Causes a cell to shrink In your textbook, read about passive transport and active transport. For each item in Column A, write the letter of the matching item in Column B. Column A Column B 5. Transport protein that provides a tubelike opening in the plasma membrane through which particles can diffuse 6. Is used during active transport but not passive transport 7. Process by which a cell takes in material by forming a vacuole around it 8. Particle movement from an area of higher concentration to an area of lower concentration 9. Process by which a cell expels wastes from a vacuole 10. A form of passive transport that uses transport proteins 11. Particle movement from an area of lower concentration to an area of higher concentration a. energy b. facilitated diffusion c. endocytosis d. passive transport e. active transport f. exocytosis g. carrier protein 12. Transport protein that changes shape when a particle binds with it h. channel protein UNIT 3 CHAPTER 8 Cellular Transport and the Cell Cycle 85
Master 19 Diffusion and Cell Size Section Focus Use with Chapter 8, Section 8.2 Glucose molecule Oxygen molecule Carbon dioxide molecule 1 What materials move through this cell by diffusion? 2 How might increasing the size of the cell affect the cell? 96 CHAPTER 8 Cellular Transport and the Cell Cycle UNIT 3
Master 8 Basic Concepts Osmosis Use with Chapter 8, Section 8.1 Before osmosis After osmosis Selectively permeable membrane Water molecule Sugar molecule Cell in Isotonic Solution Cell in Hypotonic Solution Cell in Hypertonic Solution Water molecules Dissolved particles In an isotonic solution, water molecules move into and out of the cell at the same rate. In a hypotonic solution, water enters a cell by osmosis, causing the cell to swell. In a hypertonic solution, water leaves a cell by osmosis, causing the cell to shrink. UNIT 3 CHAPTER 8 Cellular Transport and the Cell Cycle 99
Worksheet 8 Osmosis Basic Concepts Use with Chapter 8, Section 8.1 1. Look at the U-shaped tube at the top of the transparency. Why did the number of water molecules on each side of the membrane change, whereas the number of sugar molecules stayed the same? 2. How does the plasma membrane of a cell compare with the membrane in the U-shaped tube? 3. Explain the behavior of water molecules in the isotonic solution. 4. Does osmosis occur if a cell is placed in an isotonic solution? 5. Why does water enter a cell that is placed in a hypotonic solution? 6. What happens to the pressure inside a cell that is placed in a hypertonic solution? 7. What can happen to animal cells when placed in a hypotonic solution? Explain. 8. What causes a plant to wilt? 100 CHAPTER 8 Cellular Transport and the Cell Cycle UNIT 3
Master 9 Basic Concepts Active Transport Use with Chapter 8, Section 8.1 Ion Lower concentration of ions Energy Carrier protein Higher concentration of ions UNIT 3 CHAPTER 8 Cellular Transport and the Cell Cycle 101
Worksheet 9 Active Transport Basic Concepts Use with Chapter 8, Section 8.1 1. Which type of transport protein is involved in active transport? 2. Describe the concentration gradient shown in the transparency. 3. Why must cells use energy to move particles from a region of lower concentration to a region of higher concentration? 4. Describe the process of active transport. 5. What is the source of the energy used in active transport? 6. How does endocytosis differ from the process shown in the transparency? 7. Why is endocytosis considered a type of active transport? 8. What process of active transport is the reverse of endocytosis? Explain 102 CHAPTER 8 Cellular Transport and the Cell Cycle UNIT 3
Chapter 8 Cellular Transport and the Cell Cycle, continued Chapter Assessment Thinking Critically The graph shows typical concentrations of several ions inside and outside an animal cell. Concentrations of ions inside the cell are shown in gray, outside in black. Use the graph to answer questions 1 5. Na + K + CA 2+ Mg 2+ HCO 3 Cl 0 50 100 150 Concentration (mm) 1. Compared to its surroundings, does an animal cell contain a higher or lower concentration of potassium (K + ) ions? 2. Which ions are in the greatest concentration outside the animal cell? 3. Which ions are in the lowest concentration inside the animal cell? 4. What is the approximate concentration, in mm, of Mg 2+ ions inside the cell? 5. If all available Na + and Cl ions combine to form NaCl, do any excess Na + or Cl ions remain? If so, which? Answer the following question. 6. Describe the process by which a cell maintains differences in concentrations of certain ions on either side of the plasma membrane. 114 CHAPTER 8 Cellular Transport and the Cell Cycle UNIT 3
Master 11 Active Versus Passive Transport Reteaching Skills Use with Chapter 8, Section 8.1 Passive Transport high low high low outside cell inside cell outside cell inside cell Active Transport low high low high outside cell inside cell Energy to transport substance outside cell inside cell UNIT 3 CHAPTER 8 Cellular Transport and the Cell Cycle 105
Worksheet 11 Active Versus Passive Transport Reteaching Skills Use with Chapter 8, Section 8.1 1. Some people describe diffusion as the process by which something moves from where it is to where it is not. Explain why this description is accurate and why it is not. 2. Explain what is meant by concentration gradient. A. Concentration Gradient of Molecules Outside the cell Inside the cell B. The model above represents a cell in a solution. Use it to answer questions 3 and 4. 3. In space A, draw an arrow that shows the direction in which the molecules will move during passive transport. 4. In space B, draw an arrow that shows the direction in which the molecules will move during active transport. 5. What type of passive transport is shown in the transparency? Explain. 6. Why is passive transport called passive? 7. In the illustration of active transport, why is energy needed to move the particles across the plasma membrane? 8. Describe the role of carrier proteins during active transport. 106 CHAPTER 8 Cellular Transport and the Cell Cycle UNIT 3
Worksheet 12 1. Define the following terms: a. osmosis Osmosis and Hypotonic, Hypertonic, and Isotonic Solutions Reteaching Skills Use with Chapter 8, Section 8.1 b. hypotonic solution c. hypertonic solution d. isotonic solution 2. When a cell is in a hypotonic solution, how will water molecules move? 3. When a cell is in a hypertonic solution, how will water molecules move? 4. When a cell is in an isotonic solution, how will water molecules move? 5. Explain how hypotonic and hypertonic solutions can make a plant rigid and firm or make it wilt. 6. Osmosis is a form of passive transport. Explain how facilitated diffusion, which is another form of passive transport, is different from osmosis. 108 CHAPTER 8 Cellular Transport and the Cell Cycle UNIT 3