Cells make up all life on Earth. Cells are the smallest unit of life. All cells have specific structures, called components. Models in science are used to help us understand complicated ideas in a ...

A look at the cells of different organisms and a comparison of the structures found in plant and animal cells. All animal cells are surrounded by a membrane which contains the cytoplasm. Nearly all ...

Plant stem cells, as in animals, are maintained in specialized microenvironments, which are known as stem cell niches, where local signals from organizer cells act to prevent stem cell differentiation ...