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Thermodynamics of Membrane Diffusion: Charged Ion quiz

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  • What must be considered when charged ions diffuse across a membrane, unlike uncharged molecules?
    The transmembrane potential (delta psi), which is the difference in electrical charge across the membrane, must be considered.
  • What is the equation for delta G transport when only the electrical gradient is considered for ions?
    Delta G transport = z * F * delta psi, where z is the net charge, F is Faraday's constant, and delta psi is the transmembrane potential.
  • What does the variable z represent in the equation for ion transport across membranes?
    The variable z represents the net charge of the diffusing ion.
  • What is Faraday's constant (F) and what is its value?
    Faraday's constant is the magnitude of the charge of 1 mole of electrons, and its value is 96,485 coulombs per mole.
  • Is Faraday's constant positive or negative, and why?
    Faraday's constant is always positive, even though electrons are negatively charged.
  • What are the units of Faraday's constant?
    Faraday's constant can be expressed as coulombs per mole or joules per volt per mole.
  • What is the electrochemical gradient?
    The electrochemical gradient is the combination of the chemical gradient and the electrical gradient across a membrane.
  • Why do uncharged molecules not depend on the electrical gradient for membrane diffusion?
    Uncharged molecules only depend on the chemical gradient because they do not carry a charge.
  • What additional term must be included in the membrane diffusion equation for charged ions compared to uncharged molecules?
    The electrical gradient portion, z * F * delta psi, must be added for charged ions.
  • What does delta psi represent in the context of membrane diffusion?
    Delta psi represents the transmembrane potential, or the difference in electrical charge across the membrane.
  • How do you convert a unit raised to the negative one (e.g., volts^-1) in the context of Faraday's constant?
    You take the reciprocal, so volts^-1 becomes 1/volts.
  • What is the main difference in the thermodynamics of membrane diffusion between charged and uncharged molecules?
    Charged ions require consideration of both chemical and electrical gradients, while uncharged molecules only require the chemical gradient.
  • Who is Faraday's constant named after?
    Faraday's constant is named after the scientist Michael Faraday.
  • What will the next lesson video demonstrate regarding membrane diffusion for charged ions?
    The next video will show how to apply the discussed equation to calculate the thermodynamics of membrane diffusion for charged ions.
  • What must be 'tagged on' to the chemical gradient equation to account for charged ion diffusion?
    The electrical gradient portion (z * F * delta psi) must be added to the chemical gradient equation.