Nucleus, ER & Golgi Flashcards
Nuclear envelope
Double bilayer with nuclear pores, nuclear lamina - IFs - anchors to chromatin, continuous with RER
Light portions of the nucleus
Euchromatin - actively transcribed
Dark portions of the nucleus
Heterochromatin - not actively transcribed
Nucleolus
Non-membrane bound, involved in synthesis and assembly of ribosomal subunits , assembled in cytoplasm, indicator of metabolic activity, very basophilic, dark Hematoxylin staining
Fibrillar center
light areas in nucleolus
Dense fibrillar center
where rRNA subunits are made in nucleolus
Granular component
where rRNA subunits are organized in nucleolus
Nuclear bodies
Very small, structure RNA, histone gene expression, PML-gene, pre-mRNA splicing
Very condensed chromtin
apoptotic cell
Necrosis vs Apoptosis
Necrosis - injured cell, cell contents leaks out
Apoptosis - organized cell death, dark nucleus, out of normal position
Nuclear transport
Gated transport, through nuclear pores, octagonal symmetry, active transport, energy required, involving exportins and importins, needs nuclear localization protein with RAN family proteins facilitating transport
Nuclear lamina
attaches chromatin, made of IF, phosphorylated during disassembly of nucleus in prophase, dephos causes re-assembly
Progerias
gene defects in nuclear structure of lamin A and C
ER
protein synthesis, modification, lipid and steroid synthesis, detoxification of specific compounds, N-glycosylation, sequestering Ca++ (sarcoplasmic reticulum
rER
proteins projected into lumen, or in membrane then transported or modified, very basophilic, large cistern with beads attached
