Unit 2: The Cell Animations   Study Guide

Chapter 7 Membrane Structure and Function Review
  1. The plasma membrane is a "fluid mosaic" made of with a mosaic of embedded in it, and exhibits permeability.
  2. Membranes are made of which form a bilayer with embedded proteins.
  3. Selective allows some material to cross the plasma membrane.
    • (passive transport) is the tendency for molecules to spread out evenly down their gradient.
      • Osmosis determines the of the environment across a membrane.
      • Organisms without cell must have adaptations for to maintain water balance.
      • Plant cells fare best in environments.
    • diffusion is the movement of molecules across the membrane facilitated by proteins, the concentration gradient.
    • transport moves molecules their concentration gradient and requires energy.
    • Large molecules are moved into and out of cells by bulk transport mechanisms of and .
      • In , the cell takes in macromolecules by forming vesicles from the plasma membrane via invagination.
      • In , transport migrate to the plasma membrane, fuse with it, and release their contents.
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