To refer to class variables and methods, you join the class's name and the name of the class method or class variable together with a period ('.'). Methods and variables that are not class methods or class variables are known as instance methods and instance variables.nstance Methods and Variables. While System's. When the System class is loaded into the application, the class instantiates PrintStream and assigns the new PrintStream object to the. As you see, you refer to an object's instance methods and variables similar to the way you refer class methods and variables.
Mitochondria (singular mitochondrion) are abundant organelles present in nearly all eukaryotic cells . The main function of mitochondria is to produce adenosine triphosphate (ATP), the cellular energy source. Mitochondria are believed to be the evolutionary result of early anaerobic (nonoxygen-using) eukaryotic cells engulfing aerobic (oxygen-utilizing) bacteria, resulting in a symbiotic relationship between the two organisms.
Mitochondria are unusual organelles. They act as the power plants of the cell, are surrounded by two membranes, and have their own genome. They also divide independently of the cell in which they reside, meaning mitochondrial replication is not coupled to cell division. Some of these features are holdovers from the ancient ancestors of mitochondria, which were likely free-living prokaryotes. Mitochondria are thought to have originated from an ancient symbiosis that resulted when a nucleated cell engulfed an aerobic prokaryote.