Introduction to the cell | Cells | High school biology | Khan Academy Fundraiser Khan Academy 9.11M subscribers Cells are defined as the smallest structural and functional units of life, capable of carrying out all basic activities necessary for survival. Each cell works like a tiny factory, producing energy, synthesizing proteins, and maintaining life's essential processes. Cells are the microscopic units that make up living organisms. Learn about the characteristics and structures that all cells have in common, the functions they perform, the two main types of cells , and how they replicate themselves. A cell is the smallest living organism and the basic unit of life on earth. Together, trillions of cells make up the human body. Cells have three main parts: the membrane, the nucleus, and the ...
