Advanced Placement (AP) Biology Practice Exam

Which cell type is characterized by the absence of a nucleus?

1. Eukaryotic cell

2. Prokaryotic cell

3. Animal cell

4. Plant cell

The correct answer is: Prokaryotic cell

The correct choice highlights that prokaryotic cells are characterized by the absence of a nucleus. In prokaryotic cells, such as bacteria and archaea, the genetic material is not enclosed within a nuclear membrane. Instead, it typically resides in a nucleoid region, which is not separated from the cytoplasm by a membrane. This structural characteristic distinguishes prokaryotic cells from eukaryotic cells, which do contain a nucleus that houses their genetic material. Eukaryotic cells, including both plant and animal cells, have well-defined nuclei and various other membrane-bound organelles. This key structural difference is fundamental to the organization and complexity of cellular processes in different life forms. Understanding this distinction is crucial for grasping the diversity of life at the cellular level.