1. Plasma membrane: This acts as a barrier, controlling what enters and exits the cell. It's a selectively permeable membrane, meaning it allows some substances through while preventing others.
2. Cytoplasm: This is the jelly-like substance within the cell membrane, where many of the cell's metabolic processes occur. It contains various organelles and dissolved molecules.
3. DNA: This is the genetic material of the cell, containing the instructions for building and maintaining the organism.
4. Ribosomes: These are responsible for protein synthesis, translating the instructions from DNA into functional proteins.
These four components are essential for the basic functions of all life, including metabolism, growth, and reproduction.
