USA Biology Olympiad (USABO) Practice Exam

Which of the following is TRUE of prokaryotes?

1. I and II only

2. I and III only

3. II and III only

4. All of the above

The correct answer is: I and III only

Prokaryotes are unicellular organisms that lack a nucleus and membrane-bound organelles. One key feature is that their genetic material is typically organized in a single, circular DNA molecule, which is located in a region known as the nucleoid. This organization allows for efficient replication and transcription processes. Additionally, prokaryotes reproduce asexually through binary fission, a simple and rapid process that allows for rapid population growth under favorable conditions. Another important characteristic of prokaryotes is their diverse metabolic pathways. Some prokaryotes are capable of photosynthesis, while others perform chemosynthesis or are heterotrophic, relying on organic compounds for energy. Given these contexts, when evaluating the statements about prokaryotes, the correct answer reflects that statements I and III are true. The inclusion of both statements about their cellular structure and metabolic capabilities aligns with established biological knowledge. The status of II as true would also rely on specific phrasing in that statement, but by confirming the veracity of the other two statements, it supports the selection of the option that identifies I and III as correct, thereby reinforcing the comprehensive understanding of prokaryotic life.