Heredity and Variation

• Nucleus
  • It controls all the cellular activities of cell.
  • It consists of the following.
    a. Nuclear membrane – It has perforations called nuclear pores.
    b. Nucleoplasm
    c. Nucleolus
  • Nucleolus is the site of ribosomal RNA formation.
  • Network of nucleoprotein fibres are called the chromatin.
  • Chromatin contains DNA, histones (basic proteins), non-histone proteins, and RNA.
  • Chromatin threads condense and organize to form chromosome.
  • The primary constriction in t…