ch 8 Flashcards
nucleus
overview of the nucleus
largest organelle that holds DNA
site of transcription and DNA replication
main components of the nucleus
nuclear envelope
nuclear pores
chromatin
nuclear lamina
nuclear bodies
nuclear envelope
pair of phospholipid membranes
inner and outer
perinuclear space definition
space between membranes
perinuclear space function
controls nucleus shape
helps connect nucleus to other organelles
nuclear pore complexes definition
protein pores that surround membranes
nuclear pore complexes function
lets certain molecules in or out of nucleus
allows transport of tRNAs, mRNAs, proteins
nucleoporins
protein subunits that make up nuclear pore complexes
>1000 subunits make up nuclear pore
karyopherins
proteins that help transport molecules across nuclear envelope
exportins
karyopherins that export molecules from nucleus
importins
karyopherins that import molecules to the nucleus
nuclear localization sequence (NLS)
amino acid sequence
what protein detaches protein cargo from importin
Ran
what is a nuclear export signal
amino acid sequence that tells the cell it needs to exit
nuclear lamina
ring of lamin proteins linked together
controls nucleus shape
regulates chromatin and gene expression
heterochromatin is localized…
around edge of inside of nucleus
attached to nuclear lamina
condensed chromatin
euchromatin is located…
middle of nucleus
loosely condensed chromatin
transcription hubs
regions where many genes are being transcribed
replication hubs
regions where DNA is being replicated
examples of nuclear substructures
nucleolus
cajal bodies
nuclear speckles
nucleolus
dense region of nucleus
involved in ribosome production
rRNA is transcribed and processed
ribosomes are assembled
what regions are involved in RNA splicing
cajal bodies
nuclear speckles
where are components of the spliceosome assembled
cajal bodies
where are components of the spliceosome stored
nuclear speckles
