Question Details

When touched with needle, Amoeba will

Options

A

Split instantly

B

Die

C

Move away

D

Develop pseudopodia

Correct Answer :

Move away

Solution :

The correct option is Move away.

Explanation:
Amoeba proteus is a single-celled eukaryotic organism that, despite lacking a nervous system, exhibits sensitivity and responds to various external stimuli. This responsiveness is known as irritability or taxis.

When an Amoeba is touched with a mechanical stimulus, such as the sharp point of a needle, it perceives this as a localized threat or negative stimulus. The physical contact disrupts its cellular membrane and local cytoplasm flow. In response to this mechanical irritation, the Amoeba ceases its movement in the direction of the stimulus and retracts its pseudopodia from that side.

Simultaneously, it begins to form new pseudopodia on the opposite side of its body, redirecting its cytoplasmic flow (streaming of endoplasm) to crawl in the direction opposite to the needle. This movement away from a negative mechanical stimulus is a classic example of a negative thigmotaxis (a movement response oriented with respect to touch).

Unlock Our Free Library

Access expert-curated educational resources and study materials—completely free.