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[BIOB11H3] - Final Exam Guide - Everything you need to know! (192 pages long)


Department
Biological Sciences
Course Code
BIOB11H3
Professor
Dan Riggs
Study Guide
Final

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UTSC
BIOB11H3
FINAL EXAM
STUDY GUIDE

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Nuclear and chromatin structure
Vocabulary words:
Nuclear pore complex: highly selective, bidirectional transporter for
cargoes. Include inner membrane proteins and all the proteins in the
nucleoplasm; gateway that regulates flow of macromolecules b/w cell nucleus
& cytoplasm
Nuclear matrix: the network of fibres found throughout the inside of a cell
nucleus
Chromatin: chromosomes, present as highly extended nucleoprotein fibers.
Larger genomes packaged into DNA-protein complexes
Nuclear envelope: double lipid bilayer membrane which surrounds the
genetic material and nucleolus in eukaryotic cells; inner nuclear membrane &
outer nuclear membrane
Nucleoporins: family of proteins which are the building blocks of the NPC
Nuclear localization signal: stretch of AA near C-terminus, enables protein
to pass through nuclear pores and enter the nucleus
Importins: type of karyopherin that transports protein molecules into the
nucleus by binding to specific recognition sequences, called nuclear
localization signals (NLS)
Exportins: transports proteins out of the nucleus
Histones: small proteins that possess a high content of ARG and LYS
Nucleosomes: DNA and histones in repeating subunits
Scaffold: domain or small protein that is the object of mutation intended to
introduce or refine a property, while retaining the folding of the polypeptide
backbone
Topoisomerase: an enzyme that alters the supercoiled form of a DNA
molecule
Central ideas:
The nucleus is a highly structured organelle, housing the chromosomes
Movement of materials & macromolecular complexes across the nuclear
envelope is highly regulated and occurs via nuclear pore complexes
Chromatin is a complex consisting of approximately equal masses of DNA
and proteins
Importins are a class of proteins involved in recognizing proteins with
nuclear localization signals and which interact with pore complexes to
facilitate transfer
Exportins are involved in regulating movement of complexes out of the
nucleus
DNA is packaged by a hierarchal process
o The first level involves the interaction of positively charged histone
molecules that serve to neutralize the negative charges of phosphate
groups on DNA
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This interaction negate charges repulsion and creates the
11nm fiber
Histone H1 facilitates the transition to a coiled-coil (solenoid) fiber of about
30nm
The chromosome scaffold is a proteinaceous complex that organizes loop
domains of 30-300kb
Topoisomerases are a class of molecules that resolve tangles during
compaction
Chromosome territories exist where interactions may take place between
different chromosomes, and domains are dynamic and can change in
response to stimuli. These domains may move to transcription factories to
control gene expression
12.2 Control of Gene Expression in Eukaryotes: Structure and Function of the
Cell Nucleus
Larger genomes packaged into DNA-protein complexes called chromatin
The contents of the nucleus are present as a viscous, amorphous mass of
material enclosed by a complex nuclear envelope that forms a boundary b/w
the nucleus & cytoplasm
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