What is the smallest unit of life that conducts all life functions?
A. cell
B. organelle
C. tissue
D. organ
The correct answer and explanation is:
The correct answer is A. cell.
The cell is the smallest unit of life that conducts all life functions. It is considered the fundamental building block of all living organisms. All living things, whether unicellular (like bacteria and amoeba) or multicellular (like humans and plants), are composed of cells. These cells are capable of performing all the necessary life functions such as metabolism, reproduction, response to stimuli, and homeostasis.
Cells have various specialized structures called organelles (option B), which help carry out specific functions within the cell, such as energy production in mitochondria, protein synthesis in ribosomes, and waste management in the lysosomes. However, organelles alone cannot perform all the essential life functions required by an organism. They must work together within the cell.
Tissues (option C) and organs (option D) are higher levels of organization that arise from cells working together. Tissues are groups of similar cells that perform a specific function, like muscle tissue contracting to produce movement. Organs are composed of multiple types of tissues working together to perform a more complex function, like the heart pumping blood.
In contrast, the cell is the basic unit capable of sustaining life on its own. A single-celled organism, such as a bacterium, can carry out all functions necessary for life. In multicellular organisms, cells specialize to form tissues and organs, but they all share the fundamental ability to carry out life functions at the cellular level. Therefore, the cell is the smallest unit of life that conducts all essential biological processes.