User:SamLovesScience/Amoeboid movement

Crawling
Crawling is one form of amoeboid movement which starts when an extension of the moving cell (pseudopod) binds tightly to the surface. The main bulk of the cell pulls itself toward the bound patch. By repeating this process the cell can move until the first bound patch is at the very end of the cell, at which point it detaches. The speed at which cells crawl can vary greatly, but generally crawling is faster than swimming, but slower than gliding on a smooth surface. Crawling, though, isn't notably slower on uneven and irregular surfaces, while gliding gets much slower under such conditions. It seems that crawling can be either bleb-driven or actin-driven (see sections below), depending on the nature of the surface.

Gliding
Gliding is similar to crawling, but is characterized by much less adhesion to the surface, making it faster on smoother surfaces which require less traction but slower on more difficult and complicated surfaces. Some cells glide with the same mechanism as crawling, but with larger pseudopods and less surface adhesion. Other cells use a different method to glide: a small patch of the cell already touching the surface binds to the surface, after which the cytoskeleton pushes or pulls on the anchored patch to slide the cell forward. This differs from the aforementioned mechanism in that the cell does not extend a pseudopod, so you get relatively little deformation of the cell as it progresses.

Swimming
Many different prokaryotic and eukaryotic cells can swim and many of these have either flagella or cilia for that purpose. These dedicated structures are not necessary for swimming, though, as there are amoeba and other eukaryotic cells which lack flagella and cilia but can still swim, although it is slower than crawling or gliding. There are two different proposed mechanisms for amoeboid swimming. In the first the cell extends small pseudopods which then move down the sides of the cell, acting rather like paddles. In the second the cell generates an internal flow cycle, with the cytoplasm flowing backward along the membrane edge and forward through the middle, generating a force on the membrane which moves the cell forward.