Cell membranes protect and organize cells. All cells have an outer plasma membrane that regulates not only what enters the cell, but also how much of any given substance comes in. Unlike ...

Most cell signals are chemical in nature. For example, prokaryotic organisms have sensors that detect nutrients and help them navigate toward food sources. In multicellular organisms, growth ...

Microscopes are needed to study cells in detail. Cell division - AQA Chromosomes carry genetic information in a molecule called DNA. A type of cell division called mitosis ensures that when a cell ...