* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download SBI4U - Membrane Transport
Survey
Document related concepts
Magnesium transporter wikipedia , lookup
Cell culture wikipedia , lookup
Membrane potential wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Cell growth wikipedia , lookup
Signal transduction wikipedia , lookup
Cytokinesis wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell membrane wikipedia , lookup
Transcript
Transport Across Membranes 2.4 Transport Across Membranes • the movement of materials into and out of the cell is critical to a cell’s survival and functioning Passive Transport • the movement of materials across the cell membrane without the use of chemical energy (ATP) • occurs because of diffusion Diffusion • the net movement of a substance from an area of higher concentration to an area of lower concentration • dynamic equilibrium Simple Diffusion • substances move across membrane unassisted • small non-polar molecules (O2, CO2, steroid hormones, some drugs) and small polar molecules (H2O, glycerol) • larger molecules and ions can not pass through membranes unassisted Homework, p.97 #6 6a. How do size, polarity, and charge influence the ability of a substance to diffuse across a membrane? 6b. Which combinations of these factors require cells to use active transport to move a substance across a membrane? Facilitated Diffusion • diffusion across membrane assisted by integral membrane proteins called transport proteins • channel proteins vs. carrier proteins • ions, water, amino acids, sugars, etc. Homework, p.97 #2 • Facilitated diffusion is specific. What does this mean? Osmosis • the diffusion of water across a membrane • water follows concentration gradient (low solute concentration to high) until equilibrium Homework, p.97 #1 • Your biology study partner asks you a question about the concentration gradient of water. What is meant by the term “concentration gradient”? Is your study partner using the term correctly in reference to water? Explain why or why not. Osmosis • direction of osmosis changes depending on type of solution surrounding the cell: • isotonic solution • hypotonic solution • hypertonic solution Cell in Isotonic Solution 10% NaCL 90% H2O ENVIRONMENT CELL 10% NaCL 90% H2O NO NET MOVEMENT What is the direction of water movement? equilibrium The cell is at _______________. copyright cmassengale 13 Cell in Hypotonic Solution 10% NaCL 90% H2O CELL 20% NaCL 80% H2O What is the direction of water movement? copyright cmassengale 14 Cell in Hypertonic Solution 15% NaCL 85% H2O ENVIRONMENT CELL 5% NaCL 95% H2O What is the direction of water movement? copyright cmassengale 15 Homework, p.97 #4 • Distilled water is considered hypotonic to body cells. Explain. Cells and Tonicity Red Blood Cells Homework, p.97 #3 3. A red blood cell was placed in a beaker of solution. The cell immediately began to swell and finally burst. Explain what happened, referring to the cytosol of the cell and the solution in the beaker. hypotonic hypertonic isotonic hypertonic isotonic hypotonic copyright cmassengale 20 How does this impact… • …a single-celled organism living in a freshwater environment? • …a single-celled organism living in a salt-water environment? • …the roots of a plant in the spring after salt has been sprinkled during the winter? More applications… • Why can’t you water a plant with salt water? • Why do vegetables in the grocery store get sprayed with water periodically? (What would happen if they were sprayed with salt water?) Active Transport Active Transport • the movement of materials against the concentration gradient • requires cellular energy (ATP) Primary Active Transport • pumps move positively charged ions (H+, Ca2+, Na+, K+) across membranes • creates electrochemical gradient Secondary Active Transport • uses gradient established by a primary active transport pump Homework, p.97 #5 5. Compare the energy requirements of passive transport, primary active transport, and secondary active transport. Homework, p.97 #7 7a. How does the concentration of a solute on the two sides of a membrane affect passive transport? 7b. How does this concentration affect primary and secondary active transport? Bulk Transport • movement of larger substances across a cellular membrane • requires energy (ATP) • exocytosis & endocytosis Endocytosis Exocytosis Homework, p.97 #8 8a. What process is shown in the micrographs in Figure 13? (8b. Draw a labelled scientific drawing of the micrographs.) Credits • Slides #10, 11, 12, and 15 taken from Powerpoint presentations created by Cheryl Massengale, educator extraordinaire & creator of http://www.biologyjunction.com/