Mitochondria and nucleus

Question 1

structures and function of nucleus

Answer 1

• Eukaryotic genomes are compartmentalized in the nucleus
• contents of the nucleus are present as a viscous, amorphous mass of material enclosed by a complex
nuclear envelope that forms a boundary between the nucleus and cytoplasm.
• In the nucleus of a non-mitotic cell are
(1) Chromosomes - present as highly extended DNA-protein fibers, chromatin
(2) Nucleolus - irregularly shaped electron-dense structure that functions in the synthesis of
ribosomal RNA and assembly of ribosomes
(3) Nucleoplasm - the fluid substance in which the solutes of the nucleus are dissolved

Question 2

Nuclear Envelope

Answer 2

• Two cellular membranes arranged parallel to one another and separated by 10 to 50 nm
• Together these membranes contain 60 distinct transmembrane proteins, including those
which link the outer nuclear membrane with elements of the cytoskeleton
• Inner and outer nuclear membranes are fused at sites forming circular pores that contain
complex assemblies of proteins
• Outer membrane – studded with ribosomes, continuous with RER
• Space between the membranes is continuous with the ER lumen