MCB 2050 EXAM
REVIEW questions
amd answers
Nucleus - answer largest organelle, primary difference bt eu/prokaryotes
"control centre"
Nuclear 'compartmentalization' - answer nucleoplasm, nuclear matrix,
nuclear envelope, nuclear lamina
Nuclear envelope - answer boundary bt cytoplasm and nucleus
nuclear pores - answer 'doorways' in the nuclear envelope. Regulate
transport in/out of nucleus
nucleolus - answer site of ribosome synthesis
nucleoplasm - answer ordered architecture: site where chromatin is
found and where RNA processing takes place
nuclear matrix - answer fibrillar protein support 'mesh' (network); serves
in structural support and chromatin scaffold
Nucleoid - answer A dense region of DNA in a prokaryotic cell.
differences bt pro and eukaryotes? - answer eukaryotes - larger,
structurally and functionally more complex
,'compartmentalization'
each organelle contains both unique and common factors for functioning
(metabolism) biogenesis (formation) maintenance and turnover
2 main nucleus functions - answer compartmentalization of the cellular
genome and its activity
coordination of cellular activity
nucleus separation allows for: - answer unique (spatial and temporal)
regulation of gene expression in eukaryotes
Nuclear Structure: Nucleoplasm - answer fluid filled interior of the
nucleus
>30 specialized subdomains
e.g., nucleolus - irregular, dense and granular in appearance. Function in
ribosome production. Size and number (1-5) varies with cellular metabolic
activity.
Nuclear Structure: Chromosomes - answer during interphase are
organized into discrete subdomains ('territories') within the nucleus
Nuclear organization: interchromosomal channels - answer regions bt
subdomains that serve as barriers to prevent unwanted DNA-DNA and/or
DNA-protein interactions
Nuclear organization: Nuclear speckles - answer subdomains (appear as
'speckles' under fluroscence microscopy) where mRNA splicing factors are
concentrated (where mRNA processing occurs)
,often located in interchromosomal channels next to transcription factories
numerous and highly dynamic - >50 can quickly move, grow, shrink
depending on cellular need
Nuclear Structure: Nuclear matrix - answer insuluble fibrallar-like protein
network ('mesh') distributed throughout the cytoplasm
analogous to the cytoskeleton network in the cytoplasm
cytoskeleton network: filament systems - answer microtubules, actin
microfilaments and intermediate filaments
Microtubules - answer Spiral strands of protein molecules that form a
tubelike structure
actin microfilaments - answer help with cell shape, locomotion, vesicle
transport
-are constantly growing and shrinking
intermediate filaments - answer Threadlike proteins in the cell's
cytoskeleton that are roughly twice as thick as microfilaments
Nuclear matrix: Role - answer maintains overall shape of nucleus
(Structural)
serves as a 'scaffold' - organizes nuclear subdomains and anchoring
protein factors
Nuclear structure: Nuclear envelope - answer seperates te contents of
the nucleus from the cytoplasm
barrier, regulates passage of molecules bt nucleus and cytoplasm
, probides structural framework of the nucleus
Nuclear Envelope: main parts - answer membrane
lamina
pore complexes
Nuclear membranes - answer two (inner and outer) concentric
phospholipid bilayers
inner and outer separated by nuclear envelope lumen (10-50nm)
serve as barriers to the passage of ions, solutes and macromolecules bt
the nucleus and cytoplasm
outer nuclear membrane - answer continuous w rough ER
ribosomes attached to cytoplasmic surface of the outer membrane
nuclear envelope lumen is continuous w the ER lumen
inner nuclear membrane - answer unique protein composition
(functionally distinct from outer membrane)
where do inner and outer membranes join? - answer nuclear pore
complexes
Nuclear Lamina - answer A mesh-like array of protein filaments lining the
inner surface of the nuclear envelope, provides it mechanical support;
helps maintain the shape of the nucleus.
REVIEW questions
amd answers
Nucleus - answer largest organelle, primary difference bt eu/prokaryotes
"control centre"
Nuclear 'compartmentalization' - answer nucleoplasm, nuclear matrix,
nuclear envelope, nuclear lamina
Nuclear envelope - answer boundary bt cytoplasm and nucleus
nuclear pores - answer 'doorways' in the nuclear envelope. Regulate
transport in/out of nucleus
nucleolus - answer site of ribosome synthesis
nucleoplasm - answer ordered architecture: site where chromatin is
found and where RNA processing takes place
nuclear matrix - answer fibrillar protein support 'mesh' (network); serves
in structural support and chromatin scaffold
Nucleoid - answer A dense region of DNA in a prokaryotic cell.
differences bt pro and eukaryotes? - answer eukaryotes - larger,
structurally and functionally more complex
,'compartmentalization'
each organelle contains both unique and common factors for functioning
(metabolism) biogenesis (formation) maintenance and turnover
2 main nucleus functions - answer compartmentalization of the cellular
genome and its activity
coordination of cellular activity
nucleus separation allows for: - answer unique (spatial and temporal)
regulation of gene expression in eukaryotes
Nuclear Structure: Nucleoplasm - answer fluid filled interior of the
nucleus
>30 specialized subdomains
e.g., nucleolus - irregular, dense and granular in appearance. Function in
ribosome production. Size and number (1-5) varies with cellular metabolic
activity.
Nuclear Structure: Chromosomes - answer during interphase are
organized into discrete subdomains ('territories') within the nucleus
Nuclear organization: interchromosomal channels - answer regions bt
subdomains that serve as barriers to prevent unwanted DNA-DNA and/or
DNA-protein interactions
Nuclear organization: Nuclear speckles - answer subdomains (appear as
'speckles' under fluroscence microscopy) where mRNA splicing factors are
concentrated (where mRNA processing occurs)
,often located in interchromosomal channels next to transcription factories
numerous and highly dynamic - >50 can quickly move, grow, shrink
depending on cellular need
Nuclear Structure: Nuclear matrix - answer insuluble fibrallar-like protein
network ('mesh') distributed throughout the cytoplasm
analogous to the cytoskeleton network in the cytoplasm
cytoskeleton network: filament systems - answer microtubules, actin
microfilaments and intermediate filaments
Microtubules - answer Spiral strands of protein molecules that form a
tubelike structure
actin microfilaments - answer help with cell shape, locomotion, vesicle
transport
-are constantly growing and shrinking
intermediate filaments - answer Threadlike proteins in the cell's
cytoskeleton that are roughly twice as thick as microfilaments
Nuclear matrix: Role - answer maintains overall shape of nucleus
(Structural)
serves as a 'scaffold' - organizes nuclear subdomains and anchoring
protein factors
Nuclear structure: Nuclear envelope - answer seperates te contents of
the nucleus from the cytoplasm
barrier, regulates passage of molecules bt nucleus and cytoplasm
, probides structural framework of the nucleus
Nuclear Envelope: main parts - answer membrane
lamina
pore complexes
Nuclear membranes - answer two (inner and outer) concentric
phospholipid bilayers
inner and outer separated by nuclear envelope lumen (10-50nm)
serve as barriers to the passage of ions, solutes and macromolecules bt
the nucleus and cytoplasm
outer nuclear membrane - answer continuous w rough ER
ribosomes attached to cytoplasmic surface of the outer membrane
nuclear envelope lumen is continuous w the ER lumen
inner nuclear membrane - answer unique protein composition
(functionally distinct from outer membrane)
where do inner and outer membranes join? - answer nuclear pore
complexes
Nuclear Lamina - answer A mesh-like array of protein filaments lining the
inner surface of the nuclear envelope, provides it mechanical support;
helps maintain the shape of the nucleus.
