Ch 2 Summary –
Pg 57-68 Ultrastructure of Eukaryotic Cells
Cytoplasm
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The fluid region of the cell is the cyotosol
The fluid + organelles is the cytoplasm
Vacuole
 80-90% of plant cell volume
 The membrane of the vacuole is called the tonoplast
 Vacuoles contain pigments like anthocyanin (purple/red), carotene (orange)
Cell wall
 Present in plants, fungi, algae, some protists (Eukaryotes)
 Also present in prokaryotes but made of different components (see pg 60 for list)
 Primary cell wall provides mechanical strength & allows them to resist the pressure from osmosis
(water uptake)
 Secondary Cell wall in large/woody plants, trees shrubs – as the secondary cell wall thicken, the cell
dies but the secondary wall is left behind and provides a mechanical structure allowing them to grow
tall
Nucleus
 Double membrane, spherical
 Perforated (has holes punched through) with channels called nuclear pore complexes (NPC)
 The NPC controls the exchange of materials between the inside of the nucleus and the “outer”
cytoplasm
 Molecules transported OUT of the nucleus INTO the cytoplasm: RNA and ribosomal proteins
 Molecules transported IN of the nucleus FROM the cytoplasm: large molecules like proteins
 Nucleus contains chromatin (DNA) loosely dispered in the nucleus
 Contains DNA
 Contains instructions for/ control DNA replication during cell division
 Repairs genetic material
 Starts gene expression
 Controls the metabolic activities of the cell by regulating (managing) which genes are expressed.
 There can be one nucleolus or multiple nucleoli (not membrane bound themselves) found in the
nucleus. The Nucleolus produces ribosomal RNA (rRNA) which forms part of the ribosomes.
 Usually cells have 1x nucleus.
 Red Blood cells have no nucleus once mature. This allows them to maximize how much oxygen
they can carry