BIOB11H3 Study Guide - Midterm Guide: Nucleolus, Nucleoplasm, Coiled Coil
Document Summary
Nuclear envelope: double membrane system surrounding the nucleus, continuous with rer. Nuclear pore complex: basket-like structure regulating the in/out movement of molecules to nucleus. Nucleolus: subnucleus structure where rrna genes clustered, and assembly of rrnas. Chromatin fiber: dna coils with histones to form chromatin fiber. *theres approximately equal amounts of dna & proteins. Proteins include structural proteins [histones and proteins involved in dna metabolism (e. g. tfiid)] Double membrane, the nuclear envelope is continuous with the rough er. Inner surface are lined with lamina made with lamins (if class) mesh-like network. Gives strength and protection to nuclear envelope. La(cid:373)i(cid:374)a also (cid:373)ake (cid:272)o(cid:374)ta(cid:272)ts with hetero(cid:272)hro(cid:373)ati(cid:374) (cid:894)(cid:858)sile(cid:374)t (cid:272)hro(cid:373)ati(cid:374)s(cid:859)(cid:895) , sta(cid:271)ilizi(cid:374)g it. Import: proteins (enzymes associated w/ dna replication & transcription) have to move in. Export: rnas, rna/protein complexes have to be exported. Small proteins can freely diffuse into the nucleus (~40000 daltons is the (cid:858)cut-off(cid:859))
