Passive Transport 1Diffusion2

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**Passive Transport (Diffusion)** - Does not require ATP (energy). - Moves in favor of the concentration gradient: from high to low concentration. Some molecules will pass directly through the cell membrane via simple diffusion. Other molecules will need assistance, such as a protein channel, in facilitated diffusion. The goal of passive transport is to equalize concentration across the membrane, moving along the concentration gradient from a higher to a lower concentration. --- **Active Transport** - Moves against the concentration gradient: from a lower to a higher concentration. - Requires ATP. - Always involves a protein channel. - The goal is to increase the difference in concentration, making the concentration gradient even bigger. --- **Passive Transport: Osmosis** - No energy is needed. - It involves the diffusion of water through proteins called aquaporins. For more information, visit: [https://www.water-channeling-life.com/en/themes/01.html](https://www.water-channeling-life.com/en/themes/01.html) --- **Semipermeable Membrane and Osmosis** When solute molecules (such as salt or glucose) cannot pass through the cell membrane, water moves to balance the concentr...