The Latin name is from the Japanese name for T. sieboldii. T. canadensis and T. heterophylla were discovered early (before 1800) and until 1855 were simply treated as species of Pinus, but in 1842 T. sieboldii, the southern Japanese hemlock, was described as Abies tsugae.
The brains of the cell, the nucleus directs cell activities and contains genetic material called chromosomes made of DNA.
Organelles and Their Functions. The nucleus is arguably the most important organelle in the cell. It is the control center, telling all of the other organelles what to do and when to do it. The nucleus also contains all of the cell's genetic material, or its DNA. This material has all the instructions the cell needs for making proteins and many other important molecules. The nucleus is surrounded by two membranes. These membranes have many openings in them, which allow for the transport of materials into and out of the nucleus. RNA, proteins, and other molecules move out of the nucleus into the rest of the cell. The cell's chromosomes are also found in the nucleus.