Question

Alga Acetabularia is
(a) Unicellular prokaryote
(b) Multicellular prokaryote
(c) Unicellular eukaryote
(d) Multicellular eukaryote

Answer 1

Hint: It is an alga that is gigantic in size and thus used for cell biology experiments. It was used by Hammerling in his experiments which proved that the nucleus was the cell organelle responsible for controlling all the activities of the cell.

Complete Answer:
Algae is a type of plant and thus comes under eukaryotes. Acetabularia is a unicellular alga which means it comes under unicellular eukaryote. It is one of the largest unicellular organisms and belongs to the Polyphysaceae family. It is also known as mermaid’s wine glass and is found in subtropical waters. It has an unusually large nucleus and thus was selected by Hammerling for his experiments.

Additional information: Let us look at the Hammerling experiment in detail.
- The structure of Acetabularia is umbrella-like. It has a cap in the shape of an umbrella fused to a stalk that is tall and slender.
- At the base of this stalk, the foot with a large nucleus is present.
- So Hammerling, grafted the stalk of one species of Acetabularia onto the foot of another species.
- He noticed that the cap developing on the stalk was matching the species of the foot where the nucleus was present instead of the species with the stalk.
- This established that the nucleus decides the growth and other functions occurring in a cell.
So, the correct option is ‘(c) Unicellular eukaryote’.

Note:
- Another alga known as Spirulina is used as a space supplement by astronauts.
- Blue-green algae even though they are named algae come under Monera as they are prokaryotic.
- Cyanobacteria is the other name of blue-green algae and they were the first organisms to perform oxygenic photosynthesis.