Resetting the electrical charge of neurons so they can fire again.
| Feature | Active Transport | Passive Transport | | :--- | :--- | :--- | | | Low concentration → High concentration | High concentration → Low concentration | | Energy | Requires cellular energy (ATP) | No energy required | | Proteins | Requires carrier proteins/pumps | May use channel proteins or none at all | | Examples | Sodium-Potassium pump, Phagocytosis | Osmosis, Simple Diffusion, Facilitated Diffusion | | Goal | Accumulating substances, creating gradients | Reaching equilibrium | active transport definition biology
: Humans use active transport to absorb glucose from the gut into the bloodstream after the concentration in the gut has dropped below that of the blood. Active vs. Passive Transport Comparison Passive Transport Active Transport Direction →right arrow Low (Down gradient) →right arrow High (Against gradient) Energy (ATP) Not required Required Proteins Sometimes (Facilitated diffusion) Always required (Carrier proteins/Pumps) Examples Diffusion, Osmosis Sodium-potassium pump, Endocytosis Resetting the electrical charge of neurons so they
❌ “It only moves large molecules.” ✅ Moves ions (Na⁺, K⁺, Ca²⁺), sugars, amino acids, and more. Osmosis Sodium-potassium pump
Active transport is generally categorized into two main types, plus a specialized form known as bulk transport.
