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Cellular transport

Cellular transport. Biology Ms. Boyett. Key words. Homeostasis Selectively permeable Diffusion Osmosis Passive Transport Active Transport Equilibrium Hypotonic, hypertonic, isotonic. CELL MEMBRANE. Regulates what enters and leaves the cell Provides protection and support

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Cellular transport

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  1. Cellular transport Biology Ms. Boyett

  2. Key words • Homeostasis • Selectively permeable • Diffusion • Osmosis • Passive Transport • Active Transport • Equilibrium • Hypotonic, hypertonic, isotonic

  3. CELL MEMBRANE • Regulates what enters and leaves the cell • Provides protection and support • Lipid Bilayer • Tough flexible structure • Hydrophilic tails • Hydrophobic heads • Proteins • Inner or outer – peripheral & integral • Embedded

  4. Cell Membrane (continued) • Helps to maintain homeostasis – regulation of internal environment and maintenance of a stable, constant condition. • Is selectively permeable – only certain things get in or out

  5. Transport • All cells have liquid inside & outside. • Solutes – substances dissolved in liquid • Solvent – the dissolving liquid • Concentration – mass/volume • Molecules are constantly moving due to kinetic energy. • Typically, molecules move from a higher concentrated area to a lower concentrated area.

  6. Types of Transport Passive & Active • Passive – Does NOT require energy • Active – Requires energy in the form of ATP

  7. Diffusion • Molecules move from areas of higher concentration to lower concentration • Does NOT require energy = passive transport • Perfume example • Constant movement until equilibrium is reached

  8. Simple Diffusion • Basic movement across the membrane through pores • Very particular • Only small, non-charged molecules pass through • Water, oxygen, carbon dioxide, ethanol and urea

  9. Facilitated Diffusion • Does NOT require energy • Move molecules from high concentration to low concentration • Used when molecules are too big or not soluble within the membrane. • Transport is assisted by carrier proteins which are very specific for particular molecules.

  10. Steps of Facilitated Diffusion • Molecule binds to carrier protein • Protein changes its shape • Molecule squished through & is released • Protein goes back to its original shape.

  11. Ion Channels • Ions are positive and negatively charged particles. • Cannot just pass through the membrane. • Must have specific channels to get through. • Move from high to low • Some channels are always open while others have gates. • Ex: Sodium (Na+), Potassium (K+), Calcium (Ca2+), and Chlorine (Cl-)

  12. Osmosis • Diffusion of water through the membrane • Typically, there are sugars or ions in the water. • Moves water from higher to lower concentrations, no energy = passive transport

  13. Effects of Osmosis • Isotonic – equal • Hypotonic – more solutes in the cell – burst • Hypertonic – more solutes out of the cell – shrink • Plasmolysis (wilting) = when water leaves a cell & the pressure decreases. • Cytolysis = bursting cells

  14. Turgor pressure – pressure water molecules exert against the cell wall.

  15. Kidney Dialysis • 1938 – Willem Koff • When kidneys fail, wastes back up in the body and the person dies. • He determined that if you remove 20g of urea for the blood with osmosis, you prevent the back up. • Used sausage skin around a wooden drum. • Now it is used to keep people alive.

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