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Lecture 10

BIOL 1090 Lecture Notes - Lecture 10: Prenylation, Ribosome, Dna Replication

Course Code
BIOL 1090
Andrew Bendall

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Biology 1090 Lecture 10
o 5-10% of cell volume
o ca. 10 um diameter
o typically one/cell
Functions of the nucleus:
o Storage, replication and repair of genetic material
o Expression of genetic material
o Ribosome biosynthesis
Structure of the Nucleus
Nuclear envelope:
o Nuclear membrane
o Nuclear lamina
o Nuclear pores
Nuclear content:
o Chromatin
o Nucleoplasm
o Nuclear matrix
o Nucleolus
Nuclear Envelope (NE): Structure
2 parallel phospholipid bilayers
Outer membrane: binds ribosomes and is continuous with rough ER (RER)
Inner membrane: Contains integral membrane proteins that connect to nuclear lamina
Membranes separated by 10-50 nm
Intermembrane space continuous with ER lumen
Functions of Nuclear Envelope
Separates nuclear content from cytoplasm
o Separates transcription and translation
Selective barrier
o Allows limited movement of molecules between nucleus and cytoplasm
Binds nuclear lamina
The Nuclear Lamina
Thin meshwork of filaments
o Lamins (type of intermediate filament)
o Approximately 10nm diameter
o Integrity regulated by phosphorylation
Bound to inner surface of Nuclear Envelope (NE):
o via prenyl group linked to lamin polypeptide
o via integral membrane proteins
Support structure for NE
Attachment sites for chromatin
**Mutations in lamin gene (LMNA) implicated in Hutchinson-Gliford Progeria Syndrome (causes premature aging
in children)
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