Thirty-two control points ring the amoeba's center, each independently deciding whether to push outward or relax back based on a single dot product with the summed chemoattractant field from every food particle on screen. There is no pre-drawn pseudopod shape — watching the membrane bulge, round off into a smooth crawling front, and swallow a bacterium whole shows how a cell with no eyes or brain can still hunt down a moving target using nothing but local chemical gradients.
A soft-bodied amoeba that senses an inverse-square chemoattractant field from scattered food particles, extends its membrane toward the strongest signal, and engulfs prey into shrinking digestive vacuoles on contact.
Click anywhere on the canvas to drop extra food, then tune Chemotaxis Sensitivity and Actin Extension Speed to change how sharply the amoeba chases it; adjust Food Spawn Rate and Amoeba Base Size to change the pace and scale of the hunt.
Amoeboid crawling and phagocytosis use the same actin machinery that human white blood cells use to chase down and engulf bacteria, which is why immune cell movement looks so similar to a free-living amoeba's.
Phagocytosis is a form of endocytosis in which a cell engulfs a large particle, such as a bacterium or food source, by wrapping its membrane around it and pinching off an internal vacuole. Amoebae use it to feed, and immune cells like macrophages use it to destroy pathogens.
Chemotaxis is directed movement along a chemical concentration gradient. In this simulation the amoeba sums an attraction vector from every nearby food particle, weighted by inverse-square distance, and biases its pseudopod extension toward the strongest net direction.
A pseudopod is a temporary, actin-driven protrusion of the cell membrane that amoebae extend to crawl and capture prey. The simulation models the amoeba's edge as many control points that individually extend outward when they face the food direction and relax back otherwise, creating a bulging, crawling motion.
Actin monomers polymerize into branching filament networks just under the cell membrane on the side facing an attractant, physically pushing the membrane outward. When the chemical signal fades, the actin network disassembles and that region of membrane retracts.
After a food particle is engulfed, it sits inside a membrane-bound vacuole where digestive enzymes break it down over time. In the simulation each vacuole marker shrinks and fades over several seconds to represent this digestion process.