The life cycle of a cell begins and ends with what? A Birth / Death B Cell division C Energy D DNA replication
The correct answer and explanation is:
Correct Answer: B. Cell division
The life cycle of a cell begins and ends with cell division, a process in which one cell splits into two daughter cells. This cycle, known as the cell cycle, is fundamental to growth, development, repair, and reproduction in living organisms.
The cell cycle is divided into several phases. It starts with interphase, during which the cell grows (G1 phase), duplicates its DNA (S phase), and prepares for division (G2 phase). After interphase, the cell enters the mitotic (M) phase, where the nucleus divides (mitosis) and is followed by cytokinesis, the actual division of the cytoplasm into two daughter cells. Each daughter cell then begins its own cycle, making cell division both the endpoint and the beginning of the cycle.
Cell division ensures the continuity of life by allowing organisms to grow, replace dead or damaged cells, and reproduce. In single-celled organisms like bacteria, division (usually by binary fission) results in reproduction. In multicellular organisms, it is responsible for forming tissues, organs, and maintaining overall health.
This cycle is highly regulated. If regulation fails, it can lead to uncontrolled division, often resulting in cancer. Key regulatory checkpoints exist within the cycle to ensure that the DNA is properly replicated and not damaged before division continues. If errors are detected, the cycle may pause for repair or, if unrepairable, the cell may undergo programmed death (apoptosis) to protect the organism.
While DNA replication and energy use are important parts of the cell cycle, they are not its starting and ending points. Birth and death are broader terms that apply to organisms rather than individual cells. Therefore, cell division is the most accurate answer to the question.