Pseudopod (pseudopodium)A temporary arm of cytoplasm. The amoeba pushes pseudopodia out to creep along and to flow round its food, then draws them back in.
Plasma membrane (cell membrane)The thin, flexible membrane that encloses the whole cell. A pseudopod forms where the cytoplasm pushes it outward, and food is taken in through it at any point.
EctoplasmThe clear outer layer of the cytoplasm, just under the membrane. It is firmer than the endoplasm and has no granules in it.
Inside the cell 4
NucleusHolds most of the cell's DNA. A single round body suspended in the endoplasm. It has no fixed place: it shifts as the amoeba moves.
Contractile vacuoleA clear bubble that the cytoplasm's water slowly fills. Then it suddenly empties the water out of the cell. It keeps a freshwater amoeba from taking in too much water.
Food vacuoleA bubble formed round food the amoeba has engulfed. The food is digested inside it, which is why an old textbook calls it a sort of temporary stomach.
EndoplasmThe granular inner part of the cytoplasm. The nucleus, the food vacuoles and the contractile vacuole all lie in it.
How this list was compiled: Every name was checked on 2026-09-30 in two places, for facts only and with nothing copied. (1) R. W. Hegner, An Introduction to Zoology (1910), the chapter on Ameba, https://archive.org/details/introductiontozo00hegnrich, and the same author's College Zoology (1912), https://archive.org/details/collegezoology00hegn; both are in the public domain. (2) Wikipedia, text only: Amoeba (genus), Amoeba proteus, Pseudopodia, Ectoplasm (cell biology), Endoplasm and Contractile vacuole, for example https://en.wikipedia.org/wiki/Amoeba_(genus). (3) For the plasma membrane, which the 1910 book does not name: two journal abstracts on Amoeba proteus read through Europe PMC, https://europepmc.org/article/MED/11129797 and https://europepmc.org/article/MED/17602276. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work
How it works
This amoeba diagram labeled for biology class shows a single cell creeping on its pseudopods. Tap a name to read what the part does, then press Quiz me to test yourself.
Read the full guide
Reading the diagram from the outside in
Work from the outside in. The thin outline is the plasma membrane. Just under it is the clear ectoplasm, and the grainy middle is the endoplasm. In the endoplasm lie the nucleus, the food vacuoles and the contractile vacuole.
Two vacuoles that look alike
A food vacuole has food inside it, and the amoeba may have several. The contractile vacuole is clear: it fills with water and then empties it out of the cell.
An amoeba has no fixed shape, so your drawing need not match this one. The parts are what count.
Pseudopodium, ectosarc and endosarc are accepted as answers.
Questions and answers
What are the parts of an amoeba?
A plasma membrane, a clear outer ectoplasm, a granular inner endoplasm, a nucleus, a contractile vacuole and food vacuoles. The arms it pushes out are called pseudopods, or pseudopodia.
What does the contractile vacuole do in an amoeba?
It collects the extra water that enters the cell and pushes it back out. It fills slowly, empties suddenly, then forms again.
How does an amoeba move?
It pushes out a pseudopod and the rest of the cell flows into it. Pseudopods are temporary: the cell makes new ones as it goes and draws old ones back in.
How does an amoeba eat?
It has no mouth. Pseudopods flow round a smaller organism and close over it, and the food ends up inside the cell in a food vacuole, where it is digested.