Endoplasm and ectoplasm are names for the inner and outer portions of an amoeba’s cytoplasm. Ectoplasm is the clear outer cytoplasmic layer of an amoeba. Endoplasm, on the other hand, is the inner granule-rich cytoplasm of the amoeba.
An amoeba is a single cell microorganism made up of a nucleus and cytoplasm. Its ectoplasm is a clear gel, while the endoplasm is more fluid or watery and houses the majority of the cell’s granules and minute structures. The endoplasm makes up the bulk of the cell.
Endoplasm helps the amoeba with locomotion or movement. Since amoeba move by flowing its cytoplasm over surfaces, flowing the endoplasm in different directions moves the cell along. The ectoplasm steers the direction of the cell by extending itself into a pseudopodium, a gel-like ectoplasmic tube. The endoplasm then moves the cell by flowing into the pseudopodium. When all of the endoplasm flows into the pseudopodium, the extended ectoplasm, the amoeba advances itself into a new position.
The ectoplasm also is responsible for changing the direction of the pseudopodium. When the alkalinity and acidity of the water changes, the location of the pseudopodium changes. Slight changes in the alkalinity or acidity impedes movement or causes the cytoplasm to start flowing. The endoplasm is responsible for regulating the concentration of water in the cell. Since amoeba have a partial membrane, the endoplasm easily absorbs and releases excess water.