Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

What is considered the basic structural and functional unit of life?

1. Tissue

2. Organ

3. The cell

4. Organism

The correct answer is: The cell

The cell is recognized as the basic structural and functional unit of life for several reasons. Firstly, every living organism, whether unicellular or multicellular, is composed of cells. Cells are the smallest units that can carry out all life processes, such as metabolism, growth, and reproduction. In multicellular organisms, cells work together to form tissues, which in turn form organs and systems, but they remain the fundamental building blocks of life. Cells are capable of performing essential functions independently, including responding to environmental stimuli, synthesizing proteins, and maintaining homeostasis. This functionality highlights their significance as the units of structure in biology. While tissues, organs, and organisms are all higher levels of organization that depend on the presence and functionality of cells, none can perform the basic life functions on their own without cells. Therefore, the cell’s role as a versatile, self-sufficient unit makes it the cornerstone of both structure and function in all living things.