Nucleus Flashcards
Because the nucleus was thought to have formed from an invagination of the plasma membrane it has——
two lipid belayers, this continues into the endoplasmic reticulum
To fit all the DNA into the nucleus it must be——
compacted
the first levels of compaction is
the nucleosome which consists of the 200bp DNA wrapped around a histone octomer( 2xH2A, 2xH2B, 2xH3, 2xH4) and one unit of H1
Euchromatin is
lightly condensed
Heterochromatin is—
heavily condensed
Epigenetics describes—-
heritable differences in gene expression based on chromatin packing, rather than difference in DNA sequence
Transport into and out of the nucleus is regulaated by
nuclear pore complexes(NPC’s)
NPC’s are made up of about ——nucleoporins
30
NPC’s can transport up to —-molecules a sec and can transport
500 and can transport in both directions simultaneously
Folded proteins mov through the pore including—
ribosomal subunits which are very large
*_____can move freely through NPC’s making this an example of
small molecules(<5kDa)
facilitated diffusion
___are moved through NPC’s via active transport
large molecules
Importins mediates transport ____the nucleus
into
exporting mediate transport __of the nucleus
out
Whether proteins will be cytosolic or nuclear depends on?
signal sequences on protein
