Australian Year 10 Biology Practice Test

Prokaryotes are organisms that are characterized by their single-celled structure. They do not have a nucleus or other membrane-bound organelles, which distinguishes them from eukaryotes that can be either single-celled or multicellular, possessing a more complex cell structure with a defined nucleus.

The classification of organisms into prokaryotes and eukaryotes is fundamental in biology. Prokaryotes include bacteria and archaea, which thrive in diverse environments and often reproduce rapidly. This specialization allows them to perform essential roles in ecosystems, such as decomposition and nitrogen fixation.

In contrast, multicellular organisms, as the name suggests, are composed of multiple cells working together, while a cell wall refers to a structural component present in certain organisms, particularly plants and fungi, and does not describe the organism itself. Therefore, the identification of prokaryotes as single-celled organisms is a central concept in understanding cellular biology.