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Transporters quiz #1 Flashcards

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Transporters quiz #1
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  • What is facilitated diffusion and what does it require for the transport of specific molecules across cell membranes?
    Facilitated diffusion is a form of passive transport that requires specific transporter proteins to move specific molecules across cell membranes without the use of ATP.
  • Which type of transport uses transport proteins to move molecules across membranes without requiring energy input from ATP?
    Passive transport, specifically facilitated diffusion, uses transport proteins to move molecules across membranes without requiring energy input from ATP.
  • How does pyruvate enter the mitochondria in eukaryotic cells?
    Pyruvate enters the mitochondria through specific transporter proteins located in the mitochondrial membrane, which facilitate its movement into the organelle.
  • By what mechanism does glucose cross into the cell?
    Glucose crosses into the cell via transporter proteins such as the sodium-glucose symporter, which uses the sodium concentration gradient to facilitate glucose uptake into the cytosol.
  • Describe the role of the sodium-glucose symporter in glucose entry into cells.
    The sodium-glucose symporter is a transporter protein that uses the energy from the sodium concentration gradient to facilitate the uptake of glucose into the cell, even when cytosolic glucose concentrations are high. Both sodium and glucose must bind to the transporter, triggering a conformational change that allows their entry into the cytosol.
  • What conformational change occurs in transporters during the movement of molecules across membranes?
    Transporters undergo a conformational change that allows the bound molecule to pass through the membrane. This change is often triggered by the binding of specific substrates or ions.
  • Which class of ATP-driven pumps is responsible for creating acidic environments in organelles like lysosomes?
    V pumps transport hydrogen ions across organelle membranes, such as lysosomes, to create acidic environments. This is essential for processes that require low pH within these organelles.
  • What is the role of retinol in the function of bacteriorhodopsin?
    Retinol senses light energy and enables bacteriorhodopsin to pump hydrogen ions across the membrane. This process uses light as the energy source for ion transport.
  • How do ABC transporters contribute to drug resistance in cancer cells?
    ABC transporters, specifically the multidrug resistant protein group, actively expel chemotherapy drugs from cancer cells. This mechanism allows cancer cells to survive treatment by reducing drug accumulation.
  • What is the difference between symports and antiports in coupled transport?
    Symports move two molecules in the same direction across the membrane, while antiports move two molecules in opposite directions. Both use the energy from concentration gradients to facilitate transport.