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Simple and Facilitated Diffusion quiz

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  • What is passive transport and does it require energy input?
    Passive transport is the movement of molecules across the membrane without energy input; it does not require any energy.
  • In which direction do molecules move during simple and facilitated diffusion?
    Molecules move down their concentration gradients, from areas of high concentration to areas of low concentration.
  • What type of molecules can pass through the membrane via simple diffusion?
    Small, uncharged molecules can pass directly through the cell membrane via simple diffusion.
  • Does simple diffusion require the assistance of transport proteins?
    No, simple diffusion does not require any transport proteins.
  • What type of molecules typically require facilitated diffusion to cross the membrane?
    Charged molecules or ions typically require facilitated diffusion to cross the membrane.
  • What is the main difference between simple diffusion and facilitated diffusion?
    Simple diffusion does not require transport proteins, while facilitated diffusion requires transport proteins to assist molecule movement.
  • Name the two main types of transport proteins involved in facilitated diffusion.
    The two main types are porins (channels) and transporters (carriers).
  • How do porins (channels) facilitate diffusion across the membrane?
    Porins form membrane-spanning tunnels that allow molecules to pass through the membrane.
  • What is the specific function of aquaporins?
    Aquaporins are porins that specifically facilitate the rapid movement of water molecules across the membrane, enhancing osmosis.
  • How do transporter (carrier) proteins move molecules across the membrane?
    Transporters undergo conformational changes and are only open to one side of the membrane at a time, moving molecules across by changing shape.
  • Do facilitated diffusion processes require energy input?
    No, facilitated diffusion is a passive process and does not require energy input.
  • What is the role of ion channels in facilitated diffusion?
    Ion channels are a type of porin that allow charged ions to move through the membrane down their concentration gradients.
  • Why can't ions cross the membrane via simple diffusion?
    Ions are charged and cannot pass through the hydrophobic core of the membrane without the help of transport proteins.
  • What does it mean for a transporter to undergo a conformational change?
    It means the transporter changes its shape to move a molecule from one side of the membrane to the other.
  • How are porins and transporters similar in their function?
    Both porins and transporters facilitate the passive movement of molecules down their concentration gradients without energy input.