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Simple and Facilitated Diffusion quiz #3

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  • Why do facilitated diffusion and simple diffusion not require energy input from the cell?
    Both processes are forms of passive transport, meaning molecules move down their concentration gradients from high to low concentration, which occurs naturally and does not require cellular energy.
  • Describe the two main types of transport proteins involved in facilitated diffusion and how they function.
    The two main types are porins (channels) and carriers (transporters). Porins form membrane-spanning tunnels that allow specific molecules or ions to pass through, while carriers undergo conformational changes to move molecules across the membrane, being open to only one side at a time.
  • What is the main difference between simple diffusion and facilitated diffusion?
    Simple diffusion does not require a membrane protein, while facilitated diffusion uses transport proteins to move molecules across the membrane.
  • Why do both simple diffusion and facilitated diffusion not require energy input from the cell?
    Both are forms of passive transport, where molecules move down their concentration gradients from high to low concentration, which occurs naturally and does not require cellular energy.
  • What types of molecules typically move across the membrane via simple diffusion?
    Small uncharged molecules typically move across the membrane via simple diffusion.
  • Which types of molecules require facilitated diffusion to cross the cell membrane?
    Charged molecules, such as ions, require facilitated diffusion to cross the cell membrane because they cannot pass through the membrane directly.
  • Describe the two main types of transport proteins involved in facilitated diffusion and how they function.
    The two main types are porins (channels), which form membrane-spanning tunnels for specific molecules or ions, and carriers (transporters), which undergo conformational changes to move molecules across the membrane, being open to only one side at a time.
  • What is the specific function of aquaporins in facilitated diffusion?
    Aquaporins are a type of porin that specifically facilitate the rapid transport of water molecules across the cell membrane, aiding in osmosis.
  • How do carrier proteins (transporters) move molecules across the membrane during facilitated diffusion?
    Carrier proteins are only open to one side of the membrane at a time and must undergo a conformational change to transport molecules to the other side.
  • In both simple and facilitated diffusion, in which direction do molecules move relative to their concentration gradient?
    Molecules move from an area of high concentration to an area of low concentration, down their concentration gradient.