Q.What are gas vacuoles? State their functions.

Gas vacuoles are a type of inclusion body found in blue-green, purple and green photosynthetic bacteria.

• Unlike the larger membrane-bound organelles of eukaryotic cells, gas vacuoles occur within these photosynthetic bacterial cells as inclusions. …

Inclusion bodies are reserve materials stored freely in the cytoplasm of prokaryotic cells, without being bound by any membrane. Gas vacuoles are one particular kind of inclusion, occurring specifically in blue-green, purple and green photosynthetic bacteria. …

Method: Two-Part Recall — Identify the Structure, Then State Its Purpose

"What is X? State its function" questions are explicitly asking for two separate things, so treat them as two mini-answers: a definition, then a function, rather than trying to weave both into a single dense sentence.

For the definition half, the key facts to anchor on are: gas vacuoles are a type of inclusion body (meaning they're not bound by their own membrane the way a eukaryotic organelle would be), and they occur specifically in certain photosynthetic bacteria — blue-green, purple, and green types. Naming the specific group of organisms is important here, since gas vacuoles aren't a general feature of all cells. …