Like us, every cell that makes up our body can grow, reproduce, process information, respond to stimuli and carry out an amazing variety of chemical reactions. These abilities define life. We and other multicellular organisms contain billions, or trillions of cells organized into complex structures, but many organisms are only a single cell.
Even single-celled organisms exhibit all the properties that distinguish living, indicating that the cell is the fundamental unit of life. At the dawn of the 21st century we face an explosion of new data about the components of cells, the structures they contain, how they contact and influence each other. However, much remains to be learned, especially about how information flows through cells and how they decide the most appropriate way to respond.
Cell and molecular biology are a rich, integrative science that brings together the following disciplines: biochemistry, biophysics, molecular biology, microscopy, genetics, physiology, computation and developmental biology.
The simplest type of reproduction involves the division of a «parent» cell into two «daughter» cells. This occurs as part of the cell cycle, a series of events that prepare the cell to divide followed by the actual process of division, called mitosis. The eukaryotic cell cycle is usually represented as four stages. The chromosome and the DNA it contains are copied during the S (synthesis) phase. The replicated chromosome is separated during the M phase (mitosis), in which each daughter cell gets a copy of each chromosome during cell division. The M and S phases are separated by two pause or latency stages, the G1 phase and the G2 phase, during which mRNAs and proteins are synthesized.
I invite everyone to read Matias’ post with the topic of the day.