1. Plasma membrane: This thin, flexible barrier encloses the cell and regulates what enters and exits. It's essentially the cell's "gatekeeper," controlling the flow of nutrients in and waste products out.
2. Cytoplasm: This gel-like substance fills the interior of the cell and houses the organelles. It provides a medium for chemical reactions and supports the cell's structure.
3. DNA (deoxyribonucleic acid): This genetic material carries the instructions for the cell's functions and development. While the organization of DNA varies between prokaryotes and eukaryotes, it's a fundamental component in all cells.
