Cell structure and organelles
Nucleus
Nuclear pore complexes
- Composed of nucleoporins
- ↑ transcriptional activity = ↑ nuclear pore complexes
- Typically = 3000-4000
- DNA synthesis requires 106 histone molecules importing
from cytosol every 3 minutes
- Each pore complex has ≥ 1 aqueous channels allowing passive
diffusion of water soluble molecules
- Small molecules (≤ 5000 daltons) diffuse rapidly
- 17000 daltons takes 2 minutes
- Impermeable to ≥ 60000 daltons
- Receptor proteins enable specific large molecules to cross