Membrane Transport and Channels

Movement Against Concentration Gradient

• Potassium and Acid Movement: Both potassium and acid are moved against their concentration gradients, meaning from a very low concentration to a high concentration.
  • Analogy: This process is likened to taking all gases from a fart and putting them back inside someone's glove, emphasizing the energy required to move substances from an area of low concentration to high concentration.

Facilitated Diffusion and Membrane Proteins

• Assisted Diffusion: Some substances, particularly ions, require assistance for diffusion across the cell membrane. This process is called facilitated diffusion.
• Membrane Proteins: This assistance is provided by membrane proteins.
  • Open Channels (Leak Channels): These proteins are always open, allowing constant passage of specific ions.
  • Gated Channels: These channels are not always open; they have