Chapter 7: Cell Structure and Function

Chapter 7: Cell Structure and Function

1. Cells

   • Surrounded by cell membrane; contain DNA
   • Prokaryotic
     • DNA is in cytoplasm
     • Generally smaller
     • Unicellular
     • Includes bacteria
   • Eukaryotic
     • DNA is in nucleus
     • Generally larger
     • Uni/Multi Cellular
     • Contain membrane-bound organelles
     • Includes animals, plants, fungi, and protists
   • Cell Transport
     • Cell membrane - regulates what enters and leaves the cell
       • Lipid Bilayer
       • Flexible, Strong
       • Selective permeability - particle can pass through, while others cannot
     • Passive Transport - no energy required
       • Diffusion
         • Molecules in a lipid or gas spread out from high to low concentration
         • Small molecules diffuse faster
         • Particles keep moving back and forth after they spread out
           • Equilibrium is reached
       • Facilitated Diffusion
         • Molecules that can't pass the lipid bilayer or diffuse through specific protein channels
         • Osmosis
           • Diffusion of water across a selectively permeable membrane
           • Occurs when solute is not able to cross membrane
           • Water moves through an aquaporin protein channel, from a high to low concentration of water, until solutions are isotonic
             • Hypertonic - Solution has a lower concentration of water and higher concentration of solute
             • Hypotonic - Solution has a lower concentration of solute and a higher concentration of water
             • Isotonic - solutions are of equal concentrations
           • Osmotic pressure
     • Active Transport - particles move from low to high concentration; requires energy
       • Molecular Transport - requires carriers proteins that use energy to move across the membrane
       • Bulk Transport - Energy is used to move larger clumps
         • Endocytosis - large particles enter the cell, through infoldings of the membrane
           • Pinocytosis - liquid substances enter
           • Phagocytosis - solid substances enter
         • Exocytosis - large particle leave the cell, as the package fom the Golgi Apparatus fuses w/cell membrane and is secreted

2. Microscope

   • On Slide
     • M
       • P
   • In scope
     • W
       • d