BIOB11H3 Lecture Notes - Lecture 7: Centromere, Suv39H1, Ionic Strength
Document Summary
Nuclear envelope: complex membrane structure that encloses the contents of the nucleus and separates them from the cytosol. Cell nucleus has: outer nuclear membrane (onm) often has ribosomes attached to the er. Fusion of the 2 membranes form a circular pore (complex assembly of proteins) Components: chromatin: chromosomes in extended nucleoprotein fibers (dna for protein, nucleoli: specialized e- dense structure that is the site of rrna synthesis and assembly of ribosomes (can be multiple nucleoli in a single nucleus) Genes and chromosomes are organized w/i diff. regions of the nucleus (b) But are related in function, will come together in specific nuclear regions (eg. rrna in the nucleolus) (a) Tend to be closer to the middle; gene poor chr. Tend to be closer to the edges of the nucleus (c) Certain types of dna will exist in certain regions of the nucleus (observed as speckles) w/i the nucleus (d) The mrna splicing machinery is localized in about 30-50 discrete sites.
