The number of cells in plants and animals varies from species to species; it has been estimated that the human body contains around 37 trillion (3.72×10 ) cells, and more recent studies put this number at around 30 trillion (~36 … See more

Cells are broadly categorized into two types: eukaryotic cells, which possess a nucleus, and prokaryotic cells, which lack a nucleus but have a nucleoid region. Prokaryotes are single-celled organisms, whereas eu… See more

All cells, whether prokaryotic or eukaryotic, have a membrane that envelops the cell, regulates what moves in and out (selectively permeable), and maintains the electric potential of the cell. Inside the membrane… See more

Many cells also have structures which exist wholly or partially outside the cell membrane. These structures are notable because they are not protected from the external environment by the cell membrane… See more

Cell division involves a single cell (called a mother cell) dividing into two daughter cells. This leads to growth in multicellular organisms (the growth of tissue) and to procreation (vegetative reproduction) in unicellular … See more