1. Metabolism: This encompasses all the chemical reactions that occur within a cell, including breaking down nutrients for energy (catabolism), building complex molecules (anabolism), and maintaining cell structure.
2. Growth and Reproduction: Cells grow in size and eventually divide to produce new cells, ensuring the continuity of life. This process involves DNA replication, cell division, and the production of new cellular components.
3. Response to Stimuli: Cells are constantly interacting with their environment and must respond to changes in their surroundings. This can include responding to changes in temperature, pH, nutrient levels, or the presence of harmful substances.
These three functions are fundamental to all living organisms, from single-celled bacteria to complex multicellular creatures like humans.
