Cell are considered the basic unit of life because all life forms are composed of them. Some forms of life are made of one cell; others contain trillions.Continue Reading
The simplest forms of life on earth are bacteria. They are made of a single cell, and they are believed to be the first form of life to arise on earth that still exists today. While plant and animal cells are significantly more complex than bacteria, there are a number of similarities that strongly suggest that modern cells descended from bacteria.
As cells began working together, they eventually formed into distinct collections of cells. Plants and animals are the result of this evolution, and all forms of life on earth are comprised of cells with more similarities than dissimilarities. The versatile nature of cells makes them great at adapting to new roles.
Viruses are not considered cells, as they must infect a cell to reproduce and lack many structures present in other cells. When a virus is not attached or inside a cell, it is completely inert. Because of this, experts argue whether viruses should be considered a form of life. If they are alive, they represent the only non-cellular form of life known to exist on the planet.Learn more about Cells
The three fundamental propositions of classical cell theory are that the cell is the most basic unit of life, all life is made up of cells and cells are formed only by other cells. Each tenet of this theory is important to understanding the way living things function on every level.Full Answer >
The modern cell theory states that living organisms are made of cells, that all cells come from other cells and that cells are the most basic life form. As scientific advancements are made, definitions of theories, like the cell theory, are updated. The modern cell theory is not the same as cell theory of the past.Full Answer >
Cellular respiration, with a series of steps and intracellular functions, is the method used by cells to release energy from chemical bonds of molecules, such as food molecules, that provide energy and sustenance for the essential processes of life. Cellular respiration is conducted within the bodies of all living cells. This process takes place in the form of aerobic or anaerobic respiration.Full Answer >
ATP is called the energy currency of the cell, and of life, because it is the energy molecule that all cells need in order to do anything within the human body. The molecule is used like a battery within cells and allows the consumption of one of its phosphorous molecules.Full Answer >