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Simple and Facilitated Diffusion definitions Flashcards

Simple and Facilitated Diffusion definitions
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  • Diffusion
    The passive movement of molecules from an area of higher concentration to an area of lower concentration, requiring no energy.
  • Facilitated Diffusion
    Passive transport process where molecules move down their concentration gradient via specific transmembrane proteins, without energy expenditure, typically for polar or charged substances.
  • Passive Process
    Movement of molecules across a cell membrane without energy input, following the concentration gradient, either directly or via a transport protein.
  • Concentration Gradient
    The gradual difference in the concentration of solutes in a solution between two regions, leading to the movement of particles from high to low concentration.
  • Protein Transporter
    A membrane protein that facilitates the passive transport of polar or charged molecules across the cell membrane without using energy.
  • Cell Membrane
    A selective barrier composed of a lipid bilayer with embedded proteins, regulating the entry and exit of substances, maintaining homeostasis, and facilitating communication between cells.
  • Protein Channel
    A membrane-spanning protein that facilitates the passive transport of specific molecules or ions across the cell membrane, following their concentration gradient without using energy.
  • Lipid Bilayer
    A double-layered structure forming the core of cell membranes, composed of hydrophobic tails and hydrophilic heads, regulating molecule passage based on polarity and size.
  • Nonpolar
    Molecules that lack a charge and do not have regions with partial positive or negative charges, allowing them to pass through the cell membrane via simple diffusion.
  • Hydrophobic
    Repels water and other polar substances, typically nonpolar molecules that do not mix with water.
  • Polar
    Molecules with uneven distribution of electrical charge, making them hydrophilic and unable to pass through the cell membrane without a transport protein.
  • Charged Ions
    Ions with a net electric charge, either positive or negative, that cannot pass through the cell membrane via simple diffusion and require facilitated diffusion using transport proteins.
  • Hydrophilic
    Attracted to water, these molecules or substances interact well with water and other polar solvents, often requiring transport proteins to cross cell membranes.
  • Calcium Ions
    Positively charged particles essential for various cellular processes, including muscle contraction, neurotransmitter release, and signal transduction, requiring facilitated diffusion to cross cell membranes.
  • Sodium Ions
    Positively charged particles that cannot pass through the cell membrane via simple diffusion and require a transport protein for facilitated diffusion.