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Explore the vital role of cell transport in maintaining internal stability. Learn about passive and active transport mechanisms, such as diffusion, osmosis, and ion channels. Discover how cell membranes help regulate what enters and exits cells. Understand how transport processes contribute to overall homeostasis within the body.
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Transport-cell membrane • Do Now: • What is homeostasis? • What is transport? • Brainstorm: • Can you brainstorm one way that transport helps to maintain homeostasis in your body? (explain)
Definitions….. • TRANSPORT • -absorption, distribution, circulation, cyclosis, osmosis, diffusion • HOMEOSTASIS • -maintaining a stable internal environment
What does venom have to do with cell membranes? • Brown Recluse Spider Bite!
Vocabulary • Solution- mixture in which one or more substances are UNIFORMLY distributed in another. “homogenous solution” • Solute- what gets dissolved. • Solvent- what does the dissolving. • Ex- salt water- salt is solute, water is solvent. Ice tea- mix=solute, water=solvent
Names! • Cell membrane • Plasma membrane • Selectively permeable membrane • Semi permeable membrane
Honors Know diagram on pg 82! • Variety of Proteins: • I. Glycoproteins • Receptor protein • Recognition proteins • Enzymatic proteins • Attachment proteins • Transport proteins
Functions of the Cell Membrane • Protects the cell • Regulates what goes in and out of cell • Helps to communicate with other cells • Creates attachments between cells • Dynamic!
Fluid Mosaic Modeldev. By Singer & Nicolson 1972 • Proteins move within layers of lipids w/I viscous fluid • Hydrogen bonds can form between water and phospholipid heads inside and outside of cell • The more double bonds there are in the tails the more fluid the membrane • Incr. in temp. causes membr. To be more fluid (because mol. Move faster) • Decr. Temp. (mol. Move slower -> less fluid)
Active & Passive Transport Illustrations Chapter 5 Lab Biology Chapter 5 Honors Biology
Passive Transport • Requires NO energy!! • Movement from a high concentration to a low concentration!
Passive Transport • 1. diffusion • 2. osmosis • 3. facilitated diffusion • 4. diffusion through ion channels
Diffusion • Molecules moving from a greater concentration to a lower concentration • Ex: perfume • Simple diffusion: Oxygen, Carbon Dioxide, water and lipid soluble molecules
Vocabulary • Concentration gradient: difference in concentrations (amount of solute) • Equilibrium: particles/molecules are equal on both sides of membrane
Osmosis • Movement of WATER from a high concentration to a low concentration across the cell membrane
Vocabulary • Isotonic: concentration inside and outside of cell are the same no diffusion • Hypertonic: when concentration of solute outside of cell is greater, water moves out of cell (shrink) • Hypotonic: concentration of solute inside of cell is greater, water moves into cell (burst)
Plants! • Plasmolysis = cell shrinks away from cell wall due to water loss ex: drought (low rain fall) causing plants to wilt • Turgor Pressure = cell wall sustains shape, otherwise would explode
Facilitated Diffusion • Carrier Protein– -protein recognizes substance->changes shape->delivers substance to inside of the cell • Facilitated Diffusion: water soluble molecules (hydrophillic). Ex: ions, amino acids (small proteins), and sugars
Ion channels • -allows ions Ca2+ and Cl- to enter cell • Some are open all the time • Others are gated and will open when • Cell membrane stretches • Electrical signals • Chemical signals
Active Transport • REQUIRES ENERGY! • Movement from a LOW concentration to a HIGH concentation!
Active Transport • 1. Sodium Potassium Pump • 2. Endocytosis • 3. Exocytosis
Sodium Potassium Pump • -pumps like to keep ions in balance • 3 Na+ out for every 2 K+ in • This creates a build up of Na+ outside cell and K+ inside cell forming a net electrical charge across the membrane • Allows for nerve impulses • Contraction of muscles • 1/3 of all energy in animal cells goes to running this pump even as we sleep!
Endocytosis • Take in external fluid, macromolecules and other large particles. • Forms “vesicle” some fuse with lysosomes (digestion) others fuse with membrane of other organelles. • 2 Types: a) pinocytosis – cell drinking fluid • b) phagocytosis – cell eats