The nucleus is the cellular control center and exists only in eukaryotes. The nucleus contains the genetic information
for the cell, in the form of DNA
and RNA. The genetic information is surrounded by a two-layer nuclear
envelope and it is generally found at the center of the cell. The nucleus is
responsible for communicating with other organelles in the cytoplasm
(the gel-like space surrounding the nucleus). Messages from inside the nucleus
travel through pores on the nuclear envelope to enter the cytoplasm.
Inside the nucleus, called the
nucleoplasm, DNA is bound by histone proteins and organized into chromatin.
During replication, the chromatins are condensed to form highly organized
structures called chromosomes. Besides the
genetic information, most nuclei also contain one or more spherical-shaped
organelles called the nucleoli. The nucleolus is where ribosomes
Click on the links below to learn about DNA and the organization of DNA
inside of the nucleus.
DNA and RNA
Learn about the molecular blueprint of life
and its properties.
Find out how DNA is organized inside the
nucleus and learn about the different levels of DNA packing.