Why are cells considered the smallest unit of life?
a) Because a cell is the smallest thing that carries out all the functions of life
b) Because all cells have a nucleus with DNA
c) Because they have a structure.
d) Because you need a microscope to see them.
The Correct Answer and Explanation is :
The correct answer is a) Because a cell is the smallest thing that carries out all the functions of life.
Explanation:
Cells are considered the smallest unit of life because they are the fundamental building blocks of all living organisms and are capable of performing all the necessary functions that define life. These functions include metabolism, growth, reproduction, response to stimuli, and homeostasis. A single cell, whether it is part of a multicellular organism or a single-celled organism, is self-sustaining and operates as an independent system capable of performing the essential life processes.
Each cell is a highly organized structure made up of various components such as the cell membrane, cytoplasm, organelles (like the nucleus in eukaryotic cells), and genetic material. Within the cell, biochemical reactions occur that allow it to extract energy, synthesize molecules, and carry out a variety of other functions that are necessary for survival. For instance, the mitochondria in eukaryotic cells generate energy (ATP), while ribosomes are responsible for protein synthesis.
Additionally, cells have the ability to reproduce, whether through mitosis (in multicellular organisms) or binary fission (in unicellular organisms), ensuring the continuity of life. Even though cells may vary in complexity, with prokaryotic cells (like bacteria) being simpler than eukaryotic cells (like those in plants and animals), all cells share these core life functions. This is why cells are considered the smallest unit of life—they encapsulate the entire spectrum of biological processes within their structure.
The other options (b, c, d) do not fully explain why cells are considered the smallest unit of life. Not all cells have a nucleus with DNA (e.g., prokaryotic cells), and the mere fact that cells are small or have structure does not make them unique in terms of being the fundamental unit of life. Therefore, option a is the most accurate explanation.