Key Words Lectures 2-5 Flashcards
1
Q
Cellular Compartmentalization
A
allows for larger size and segregation and organization of specific cellular functions
2
Q
Nucleus
A
2 main functions:
1. ** Compartmentalization of the cellular genome and its activities **(ie: site of DNA rep. and site where translation cmponents are synthesized
2. Coordination of cellular activities (ie: metabolism, protein synthesis, cell division etc.)
3
Q
Nucleoid
A
- only in prokaryotes
- region where chromosome is located
- less DNA and DNA packaging and limited/no RNA processing
4
Q
Nucleolus
A
- most conspicuous nuclear subdomain (irregular shaped, dense and granular)
- size and number depend on metabolic activity of cell
- function in producing ribosomes (rDNA transcription, rRNA processing, initial stages of ribosomal subunit)
5
Q
Nucleoplasm
q
A
- fluid-filled interior of nucleus
- has >30 specialized subdomains that participate in specific functions (nuclear subomains are not membrane bound)
6
Q
Transcription Factories
A
- formed by active genes of different subdomains that extend into interchromosomal channels
- where transcription factors are concentrated
7
Q
Interchromosomal channels
A
- regions between chromosome subdomains
- serve as barriers to prevent unwanted DNA-DNA and/or DNA-protein interactions
8
Q
Nuclear speckles
A
- subdomains of nucleus where mRNA splicing factors are concentrated (where pre-mRNA processing occurs)
- often located in interchromosomal channels next to transcription factories
- numerous and highly dynamic
9
Q
Nuclear Matrix
A
- insoluble fibrillar-like protein network distributed throughout nucleoplasm
- structural role - maintains overall shape of nucleus
- serves as a scaffold - responsible for organizing nuclear subdomains and anchoring protein factors
10
Q
Nuclear Envelope
A
- seperates contents of nucleus (ie: genome) from surrounding cytoplasm
- serves as a barrier which requires regulated passage of molecules between nucleus and cytoplasm
- establishes unique composition of nucleus and spatially regulates gene expression
- provides structural framework for nucleus
- 3 main parts (nuclear membranes, nuclear lamina, nuclear pore complexes)
11
Q
Inner Nuclear Membrane
A
- has a unique protein composition
- joined to outer nuclear membrane at nuclear pore complexes
- phospholipid bilayer
- serves as a barrier to passage of ions, solutes, macromolecules between nucleus and cytoplasm
12
Q
Outer Nuclear Membrane
A
- continuous with rough endoplasmic reticulum
- ribosomes attached to cytoplasmic surface
- joined to inner nuclear membrane at nuclear pore complexes
- phospholipid bilayer
- serve as barrier to passage of ions, solutes, macromolecules between nucleus and cytoplasm
13
Q
Nuclear envelope lumen
A
- continuous with ER lumen
- seperates inner and outer nuclear membranes
14
Q
Nuclear Lamina
A
- on inner surface (nucleoplasmic side) of nuclear inner membrane
- network of long, filament-like proteins
- provides mechanical support to nuclear envelope
- serves as scaffold fpr attachment of chromatin and nuclear matrix to nuclear envelope
- mutations in these genes are responsible for several human diseases (ie: Hutchinson-Gilford Progeria)
15
Q
ABC Nuclear Lamins
A
- evolutionarily related to proteins that form intermediate filaments in cytoskeleton network
16
Q
Nuclear Pore Complex
A
- channels in nuclear envelope
- regulated trafficking of all substances between nucleus and cytoplasm
- 3000-4000/nucleus ; number is related to nuclear activity
- 8-fold symmetrical structure organized around large, central aqueous channel
17
Q
Nucleoporin
A
- compose the nuclear pore complex
- include intergral and peripheral inner and outer nuclear membrane proteins
- several are related to COPII proteins
- highly conserved among all eukaryotes